KEY TO GROUPS

1a. Trees, shrubs, or woody climbers, with stems which last from year to year[Group 1, WOODY PLANTS], p. ix
1b. Herbaceous plants, with stems which live above ground only a single season [— 2.]
2a. Plants with unusual habits or structures, including leafless, colorless, submerged, floating, parasitic, or hollow-leaved plants[Group 2, UNUSUAL PLANTS], p. xxiii.
2b. Ordinary terrestrial or swamp plants, without unusual structural peculiarities [— 3.]
3a. Leaves parallel-veined (or net-veined in a few species); parts of the flower usually in threes or sixes, never in fives; wood-fibers scattered through the stem; seed with one cotyledon. All plants with definitely parallel-veined leaves may be identified through this division, unless the parts of the flower are distinctly in fives.[Group 3, MONOCOTYLEDONES],
p. xxvii.
3b. Leaves net-veined (or parallel-veined in a few species); parts of the flower usually in fours or fives; wood-fibers arranged in a circle in the stem; seeds with two cotyledons. All plants with definitely net-veined leaves may be identified through this division.[Group 4, DICOTYLEDONES],
p. xxx.

Note:—In order to avoid possible chances of error, many plants have been treated under both of the above groups. The following hints may also be useful in distinguishing Groups 3 and 4:

All herbaceous plants with deeply lobed, dissected or compound leaves may be sought under the Dicotyledones.

All herbaceous plants with five stamens in each flower, or with seven or more stamens and one ovary in each flower, may be sought under Dicotyledones.

GROUP 1, WOODY PLANTS

1a. Trees, with erect stem and central trunk, attaining a height of 6 m. (20 ft.) or more [— 2.]
1b. Shrubs or woody vines, without true tree habit, or attaining heights of less than 6 m. (20 ft.) [— 52.]
2a. Key for use in earliest spring, for trees which have flowers but no leaves [— 3.]
2b. Key for use with trees bearing leaves [— 21.]
3a. Flowers in catkins, without brightly colored or petal-like parts [— 4.]
3b. Flowers not in catkins, either with or without petals [— 14.]
4a. Leaf-scars and lateral buds 2-ranked, i. e., in two longitudinal rows with the third leaf above the first [— 5.]
4b. Leaf-scars and buds in three or more longitudinal rows [— 9.]
5a. From 1 to 3 bud-scales visible on each leaf-bud[2b, in FAGACEAE], p. 22.
5b. From 4 to 7 bud-scales visible on each leaf-bud [— 6.]
5c. From 8 to 20 bud-scales visible on each leaf-bud; buds long and slender; bark of the trunk smooth [— 8.]
6a. Bundle-scars 5 or more[2b, in URTICACEAE], p. 23.
6b. Bundle-scars 3 [— 7.]
7a. Twigs bearing numerous dwarf branches thickly covered with crowded leaf-scars (Birch)[BETULACEAE], p. 21.
7b. Twigs without dwarf branches (Ironwood)[9a, in BETULACEAE], p. 22.
8a. Trunk cylindrical or nearly so[2a, in FAGACEAE], p. 22.
8b. Trunk prominently fluted with longitudinal ridges[1b, in BETULACEAE], p. 21.
9a. Bundle-scars 3 in each leaf-scar [— 10.]
9b. Bundle scars more than 3 in each leaf-scar [— 12.]
10a. Pith divided into separate cavities by transverse partitions[1a, in JUGLANDACEAE], p. 21.
10b. Pith not partitioned [— 11.]
11a. Buds small, with only one external bud-scale[1b, in SALICACEAE], p. 19.
11b. Buds with more than one outer bud-scale[1a, in SALICACEAE], p. 19.
12a. Buds clustered near the tips of the twigs[1b, in FAGACEAE], p. 22.
12b. Buds not clustered at the tips of the twigs [— 13.]
13a. Buds with about 3 visible bud-scales[2b, in FAGACEAE], p. 22.
13b. Terminal bud large, with 4 or more visible bud-scales[1b, in JUGLANDACEAE], p. 21.
14a. Flowers conspicuous, brightly colored, at least 8 mm. wide. with both calyx and corolla [— 15.]
14b. Flowers inconspicuous, seldom brightly colored, and then less than 8 mm. wide [— 17.]
15a. Flowers irregular, pink or red[3a, in LEGUMINOSAE], p. 58.
15b. Flowers regular, white [— 16.]
16a. Ovary one, superior, in the center of the flower[32b, in ROSACEAE], p. 54.
16b. Ovary inferior, appearing as a swelling below the calyx at the summit of the pedicel[42b, in ROSACEAE], p. 55.
17a. Leaf-scars and buds opposite [— 18.]
17b. Leaf-scars and buds alternate [— 19.]
18a. Bundle-scar one in each leaf-scar[1b, in OLEACAE], p. 88.
18b. Bundle-scars 3 or more in each leaf-scar[ACERACEAE], p. 70.
19a. Bundle-scar 1 in each leaf-scar[1b, in LAURACEAE], p. 41.
19b. Bundle-scars 3 in each leaf-scar [— 20.]
19c. Bundle-scars 5 in each leaf-scar[7a, in LEGUMINOSAE], p. 58.
20a. Branches thorny[5a, in LEGUMINOSAE], p. 58.
20b. Branches not thorny[3a, in URTICACEAE], p. 24.
— 21—
21a. Leaves narrow, needle-like or scale-like; trees mostly evergreen[PINACEAE], p. 1.
21b. Leaves broader, flat, never needle-like or scale-like, falling in winter [— 22.]
22a. Leaves compound [— 23.]
22b. Leaves simple [— 29.]
23a. Leaves opposite [— 24.]
23b. Leaves alternate [— 26.]
24a. Leaves palmately compound with 5-7 leaflets[SAPINDACEAE], p. 70.
24b. Leaves pinnately compound [— 25.]
25a. Leaflets 3-5[1a, in ACERACEAE], p. 70.
25b. Leaflets 7-11[1b, in OLEACEAE], p. 88.
26a. Stem or branches thorny[4a, in LEGUMINOSAE], p. 58.
26b. Stem or branches not thorny [— 27.]
27a. Leaflets entire[7a, in LEGUMINOSAE], p. 58.
27b. Leaflets entire except for a few large glandular teeth near their base[SIMARUBACEAE], p. 65.
27c. Leaflets serrate their entire length [— 28.]
28a. Upper leaflets less than 25 mm. wide[4b, in ROSACEAE], p. 51.
28b. Upper leaflets more than 25 mm. wide[JUGLANDACEAE], p. 21.
29a. Leaves opposite [— 30.]
29b. Leaves alternate [— 32.]
30a. Leaves entire[CORNACEAE], p. 83.
30b. Leaves toothed or lobed, not entire [— 31.]
31a. Leaves lobed[1b, in ACERACEAE], p. 70.
31b. Leaves merely toothed[27b, in CAPRIFOLIACEAE], p. 111.
32a. Leaves entire [— 33.]
32b. Leaves toothed [— 36.]
32c. Leaves lobed [— 47.]
33a. Leaves heart-shape[3a, in LEGUMINOSAE], p. 58.
33b. Leaves not heart-shape [— 34.]
34a. Twigs and foliage spicy-aromatic[1b, in LAURACEAE], p. 41.
34b. Twigs and foliage not aromatic [— 35.]
35a. Pith 5-angled; fruit an acorn[3a, in FAGACEAE], p. 22.
35b. Pith not 5-angled; fruit a berry[1a, in CORNACEAE], p. 83.
36a. Leaves oblique at base, i. e., one side of the leaf larger than the other [— 37.]
36b. Leaves symmetrical, not oblique at base [— 38.]
37a. Leaves heart-shape, about as broad as long[TILIACEAE], p. 72.
37b. Leaves oval or ovate, much longer than wide[1a, in URTICACEAE], p. 23.
38a. Stems thorny[41b, in ROSACEAE], p. 54.
38b. Stems not thorny [— 39.]
39a. Leaves finely toothed, with 3-many teeth per centimeter of margin [— 40.]
39b. Leaves coarsely toothed, with 1-2 teeth per centimeter of margin [— 46.]
40a. Petioles laterally compressed[2a, in SALICACEAE], p. 19.
40b. Petioles not compressed [— 41.]
41a. Leaves, or many of them, crowded on short spur-like branches [— 42.]
41b. Leaves scattered, not on short spur-like branches [— 43.]
42a. Bark of the trunks separating in thin papery or leathery sheets[BETULACEAE], p. 21.
42b. Bark of the trunk not papery or leathery[24b, in ROSACEAE], p. 53.
43a. Lateral leaf-veins straight and parallel, and terminating in the teeth[BETULACEAE], p. 21.
43b. Lateral veins more or less curved, and not ending in the teeth [— 44.]
44a. Leaves palmately veined, about as broad as long; juice somewhat milky[2b, in URTICACEAE], p. 23.
44b. Leaves pinnately veined; juice not milky [— 45.]
45a. Willows, with slender leaves and brittle twigs[8a, in SALICACEAE], p. 19.
45b. Trees with lanceolate, ovate, or oblong leaves and tough twigs[30, in ROSACEAE], p. 54.
45c. Cottonwoods, with broad, heart-shape or rounded leaves[1a, in SALICACEAE], p. 19.
46a. Petioles laterally compressed[2a, in SALICACEAE], p. 19.
46b. Petioles not compressed; lateral veins straight and parallel, running directly to the teeth[FAGACEAE], p. 22.
47a. Stem thorny[41b, in ROSACEAE], p. 54.
47b. Stem not thorny [— 48.]
48a. Leaves palmately veined [— 49.]
48b. Leaves pinnately veined [— 51.]
49a. Lobes of the leaf entire[1b, in LAURACEAE], p. 41.
49b. Lobes of the leaf serrate [— 50.]
50a.Juice somewhat milky; lateral buds visible[2b, in URTICACEAE], p. 23.
50b.Juice not milky; lateral buds covered by the base of the petiole[PLATANACEAE], p. 51.
51a. Leaves with 4 large entire lobes; stem marked with a ring at each node[MAGNOLIACEAE], p. 40.
51b. Leaves with many lobes; stem not ringed[1b, in FAGACEAE], p. 22.
— 52—
52a.For specimens bearing leaves only [— 53.]
52b. For specimens bearing flowers only [— 140.]
52c.For specimens with both leaves and flowers [— 155.]
53a. Leaves narrow, needle-like or scale-like, mostly evergreen [— 54.]
53b. Leaves broader, flat or rolled, but not needle-like or scale-like [— 56.]
54a. Foliage densely gray-pubescent; low bushy shrubs with yellow flowers[2a, in CISTACEAE], p. 74.
54b.Foliage green [— 55.]
55a. Leaves opposite or whorled[PINACEAE], p. 1.
55b. Leaves scattered on the stem[TAXACEAE], p. 2.
56a.Twining or climbing vines [— 57.]
56b. Not climbing or twining [— 66.]
57a. Thorny vines [— 58.]
57b. Not thorny [— 60.]
58a.Climbing by tendrils at the base of the leaves[4b, in LILIACEAE], p. 11.
58b.Tendrils none [— 59.]
59a. Leaves simple[5a, in SOLANACEAE], p. 100.
59b. Leaves compound[8a, in ROSACEAE], p. 52.
60a.Leaves compound [— 61.]
60b.Leaves simple [— 63.]
61a. Leaves with 5 leaflets[1a, in VITACEAE], p. 71.
61b. Leaves with 3 leaflets [— 62.]
62a. Plant climbing by tendril-like leaf-stalks[1a, in RANUNCULACEAE], p. 35.
62b. Plant climbing by hold-fast roots[5b, in ANACARDIACEAE], p. 69.
63a. Leaves opposite[5a, in CAPRIFOLIACEAE], p. 110.
63b. Leaves alternate [— 64.]
64a. Plants climbing by tendrils[1b, in VITACEAE], p. 71.
64b. Twining plants [— 65.]
65a. Leaves ovate-oblong, attached by the base[1a, in CELASTRACEAE], p. 69.
65b. Leaves almost round, peltate near the edge[MENISPERMACEAE] p. 40.
66a. Leaves opposite [— 67.]
66b. Leaves alternate [— 84.]
67a. Leaves compound [— 68.]
67b. Leaves simple [— 69.]
68a. Leaflets 3[STAPHYLEACEAE], p. 69.
68b. Leaflets 7 or more[1a, in CAPRIFOLIACEAE], p. 109.
69a. Leaves palmately veined, or at least with a pair of prominent lateral veins from the base [— 70.]
69b. Leaves pinnately veined [— 72.]
70a. Leaves not lobed[1b, in RHAMNACEAE], p. 71.
70b. Leaves more or less lobed [— 71.]
71a. Leaves with stipules[22a, in CAPRIFOLIACEAE], p. 111.
71b. Leaves without stipules[2a, in ACERACEAE], p. 70.
72a. Leaves serrate [— 73.]
72b. Leaves entire [— 77.]
73a. Stem thorny[1b, in RHAMNACEAE], p. 71.
73b. Stem not thorny [— 74.]
74a. Bark of the ripe twigs green[1b, in CELASTRACEAE], p. 69.
74b. Bark of the ripe twigs brown, reddish, or gray [— 75.]
75a. Twigs with a prominent hairy ridge extending downward from the middle of the line connecting the petiole bases[13a, in CAPRIFOLIACEAE], p. 110.
75b. Twigs without any pubescent ridge [— 76.]
76a. Erect shrubs; leaves obviously toothed[11b, in CAPRIFOLIACEAE], p. 110.
76b. Spreading shrubs; most of the leaves entire, and only here and there some with serrate margins[18b, in CAPRIFOLIACEAE], p. 110.
77a. Leaves silvery beneath with a dense coating of scales[ELAEAGNACEAE], p. 77.
77b. Leaves green beneath, or somewhat hairy and light-colored [— 78.]
78a. Aquatic plant with lanceolate leaves, and stems bending over and into the water[1a, in LYTHRACEAE], p. 77.
78b. Not truly aquatic, although frequently in wet places [— 79.]
79a. Leaves evergreen, as shown by their presence on the older stems[18a, in ERICACEAE], p. 85.
79b. Leaves deciduous each year [— 80.]
80a. Leaves dotted with translucent dots, easily seen when the leaf is held to the light[1a, in HYPERICACEAE], p. 73.
80b. Leaves not dotted with translucent dots [— 81.]
81a. Lateral veins curved forward and running almost parallel to the leaf-margin[CORNACEAE], p. 83.
81b. Lateral veins spreading, and not paralleling the leaf-margin [— 82.]
82a. Leaves with stipules[1a, in RUBIACEAE], p. 108.
82b. Leaves with a prominent ridge connecting them at the base [— 83.]
82c. Leaves with neither stipules nor connecting ridges[1a, in OLEACEAE], p. 88.
83a. Bundle-scar one in each leaf-scar[18b, in CAPRIFOLIACEAE], p. 110.
83b. Bundle-scars three in each leaf-scar (Honeysuckle)[12, in CAPRIFOLIACEAE], p. 110.
84a. Leaves compound [— 85.]
84b. Leaves simple [— 95.]
85a. Stems prickly or thorny [— 86.]
85b. Stems without prickles or thorns [— 88.]
86a. Leaves twice-pinnate[1a, in ARALIACEAE], p. 80.
86b. Leaves evenly pinnate[5b, in LEGUMINOSAE], p. 58.
86c. Leaves odd-pinnate or trifoliate [— 87.]
87a. Leaflets entire 1a,[1a, in RUTACEAE], p. 65.
87b. Leaflets serrate 3b,[3b, in ROSACEAE], p. 51.
88a. Leaflets 3 [— 89.]
88b. Leaflets 5 to many [— 91.]
89a. Tall shrubs; leaflets entire or minutely toothed[1b, in RUTACEAE], p. 65.
89b. Shrubs 2 m. high or less; leaves conspicuously toothed [— 90.]
90a. Stipules present[17b, in ROSACEAE], p. 53.
90b. Stipules none[1b, in ANACARDIACEAE], p. 68.
91a. Leaflets 6-25 mm. long [— 92.]
91b. Leaflets 30 mm. long, or more [— 93.]
92a. Leaflets mostly 5, rarely 3 or 7[7a, in ROSACEAE], p. 52.
92b. Leaflets mostly 9-19, 15 mm. long or more[26a, in LEGUMINOSAE], p. 60.
92c. Leaflets mostly 25-45, less than 15 mm. long[8a, in LEGUMINOSAE], p. 58.
93a. Leaflets entire[3a, in ANACARDIACEAE], p. 68.
93b. Leaflets entire, except for 1-4 large glandular teeth near their base[SIMARUBACEAE], p. 65.
93c. Leaflets toothed throughout [— 94.]
94a. Juice milky[1a, in ANACARDIACEAE], p. 68.
94b. Juice not milky[3a, in ROSACEAE], p. 51.
95a. Leaves minute, scale-like, appressed[2a, in CISTACEAE], p. 74.
95b. Leaves 3-10 mm. long, spreading, completely rolled into a tube[EMPETRACEAE], p. 68.
95c. Leaves normal in shape, green in color [— 96.]
96a. Leaves evergreen, as shown by their presence on the older parts of the stem[4b, in ERICACEAE], p. 84.
96b. Leaves deciduous [— 97.]
97a. Stems or branches thorny [— 98.]
97b. Stems or branches without thorns or thorny leaves [— 103.]
98a. Leaves conspicuously palmately veined [— 99.]
98b. Leaves pinnately veined, or sometimes with smaller lateral veins arising from the end of the petiole [— 100.]
99a. Leaves 5 cm. wide or less[1a, in SAXIFRAGACEAE], p. 49.
99b. Leaves 15 cm. wide or more[1a, in ARALIACEAE], p. 80.
100a. Leaves entire[5a, in SOLANACEAE], p. 100.
100b. Leaves toothed or somewhat lobed [— 101.]
101a. Leaves with bristly margins; some of the thorns three-pointed[2a, in BERBERIDACEAE], p. 40.
101b. Leaves not bristly on the margin; thorns not branched [— 102.]
102a. Only lateral thorns present[41b, in ROSACEAE], p. 54.
102b. Only terminal thorns present[2a, in RHAMNACEAE], p. 71.
103a. Leaves palmately veined, or with one or more pairs of lateral veins from the base of the leaf [— 104.]
103b. Leaves pinnately veined [— 111.]
104a. Leaves entire [— 105.]
104b. Leaves toothed [— 106.]
104c. Leaves palmately lobed [— 108.]
105a. Foliage fragrant when crushed; leaves ovate[1b, in LAURACEAE], p. 41.
105b. Foliage not aromatic; leaves heart-shape[3b, in LEGUMINOSAE], p. 58.
106a. Lateral veins straight and parallel, running to the teeth of the leaf[3a, in BETULACEAE], p. 22.
106b. Lateral veins curved or branched, and not running straight to the teeth [— 107.]
107a. Tall shrubs with somewhat milky juice and broadly ovate leaves[2b, in URTICACEAE], p. 23.
107b. Low shrubs less than 1 m. high with watery juice[1b, in RHAMNACEAE], p. 71.
108a. Leaves with 2 or 3 entire lobes, spicy-fragrant when crushed[1b, in LAURACEAE], p. 41.
108b. Leaves with milky juice[2b, in URTICACEAE], p. 23.
108c. Leaves neither spicy-fragrant nor with milky juice [— 109.]
109a. Stem covered with brown bristles[29, in ROSACEAE], p. 54.
109b. Stem not bristly [— 110.]
110a. Sides of the petiole strongly decurrent on the stem; bundle-scars crowded or nearly in contact in the leaf-scars[28b, in ROSACEAE], p. 53.
110b. Sides of petiole little decurrent or not at all; bundle-scars distinctly separate[2b, in SAXIFRAGACEAE], p. 49.
111a. Leaves aromatically fragrant when crushed [— 112.]
111b. Leaves not aromatically fragrant when crushed [— 113.]
112a. Leaves broadly obovate, entire; a common woodland shrub[1a, in LAURACEAE], p. 41.
112b. Leaves linear-lanceolate or oblanceolate, conspicuously toothed or entire[MYRICACEAE], p. 20.
113a. Leaves entire [— 114.]
113b. Leaves toothed or lobed [— 121.]
114a. Base of the petiole covering the axillary buds; twigs marked with rings[THYMELAEACEAE], p. 77.
114b. Base of petiole not covering the bud, and twigs not marked with rings [— 115.]
115a. Pith with prominent partitions; tall shrubs with fetid bark; leaves obovate, 10 cm. long or larger[ANONACEAE], p. 40.
115b. Pith not partitioned; leaves smaller [— 116.]
116a. Leaves waxy or resinous underneath[24b, in ERICACEAE], p. 86.
116b. Leaves not waxy or resinous [— 117.]
117a. Lateral veins curved forward and almost parallel to the margin of the leaf[2a, in CORNACEAE], p. 83.
117b. Lateral veins spreading [— 118.]
118a. Leaves lanceolate or linear, much longer than wide [— 119.]
118b. Leaves ovate or elliptical [— 120.]
119a. Stem weak, spreading or trailing[5a, in SOLANACEAE], p. 100.
119b. Stems, or some of them, erect[3b, in LEGUMINOSAE], p. 58.
120a. Leaves with purple petioles, which are at least one-fourth as long as the leaf-blade[1a, in AQUIFOLIACEAE], p. 69.
120b. Leaves with short petioles or sessile[24c, in ERICACEAE], p. 86.
121a. Lateral veins straight and parallel, mostly ending in the teeth of the leaf [— 122.]
121b. Lateral veins not straight and parallel [— 129.]
122a. Leaves 2-ranked, i. e., in two longitudinal rows, with the third leaf directly above the first [— 123.]
122b. Leaves not 2-ranked [— 127.]
123a. Leaves unsymmetrical, oblique at the base, i. e., with one side of the leaf larger than the other[HAMAMELIDACEAE], p. 51.
123b. Leaves symmetrical or nearly so at the base [— 124.]
124a. Lateral leaf-veins ending in the leaf-teeth [— 125.]
124b. Lateral veins not ending in the teeth[42b, in ROSACEAE], p. 55.
125a. Bark smooth and fluted on the large stems[1b, in BETULACEAE], p. 21.
125b. Bark rough or warty or glandular [— 126.]
126a. Leaves 4 cm. long or less[3a, in BETULACEAE], p. 22.
126b. Leaves 5 cm. long or more[9b, in BETULACEAE], p. 22.
127a. Pith 3-angled[6a, in BETULACEAE], p. 22.
127b. Pith 5-angled[13b, in FAGACEAE], p. 23.
127c. Pith cylindrical [— 128.]
128a. Leaves finely serrate[42b, in ROSACEAE], p. 55.
128b. Leaves coarsely or doubly serrate[41a, in ROSACEAE], p. 54.
129a. Leaves coarsely or doubly serrate [— 130.]
129b. Leaves simply serrate [— 131.]
130a. Leaves 2-ranked, i. e., in two longitudinal rows, with the third leaf directly over the first[9b, in BETULACEAE], p. 22.
130b. Leaves not 2-ranked[41a, in ROSACEAE], p. 54.
131a. Leaves with glands on the petiole or at the base of the leaf-blade [— 132.]
131b. Leaves with small dark glands on the upper side of the mid-vein[42a, in ROSACEAE], p. 54.
131c. Leaves without glands [— 133.]
132a. Willows; with usually slender leaves, frequently conspicuous broad stipules, and lateral buds protected by a single external bud-scale[13, in SALICACEAE], p. 20.
132b. Plums and cherries; with leaves lanceolate or broader, and stipules minute and falling early in the season; lateral buds with more than one bud-scale[30, in ROSACEAE], p. 54.
133a. With stipules or with stipular scars indicating where stipules have been detached [— 134.]
133b. Without stipules or stipular scars [— 138.]
134a. With three bundle-scars in each leaf-scar [— 135.]
134b. With one bundle-scar in each leaf-scar [— 136.]
135a. Willows; usually with slender leaves and twigs and frequently with large conspicuous stipules; lateral buds covered by a single external bud-scale[13, in SALICACEAE], p. 20.
135b. Juneberries; with oblong or ovate leaves and small stipules which fall early; lateral buds with more than one external scale[42b, in ROSACEAE], p. 55.
136a. Leaves mostly entire, only a few here and there with low teeth[1a, in AQUIFOLIACEAE], p. 69.
136b. Leaves sharply toothed [— 137.]
137a. Axillary buds superposed, i. e., with a second one just above the first[1b, in AQUIFOLIACEAE], p. 69.
137b. Axillary buds not superposed[2b, in RHAMNACEAE], p. 71.
138a. Leaves with purple petioles, which are at least one-fourth as long as the blade[1a, in AQUIFOLIACEAE], p. 69.
138b. Leaves short-petioled or sessile [— 139.]
139a. Stems erect and straight, unbranched or with very few branches[27, in ROSACEAE], p. 53.
139b. Stems more or less crooked and freely branched, making a spreading shrub[25, in ERICACEAE], p. 86.
— 140—
140a. Flowers appearing in autumn, after the leaves have fallen[HAMAMELIDACEAE], p. 51.
140b. Flowers appearing in spring, before the leaves have opened [— 141.]
141a. Flowers in catkins, without brightly colored or petal-like parts [— 142.]
141b. Flowers not in catkins, either with or without brightly colored or petal-like parts [— 149.]
142a. Leaves 2-ranked, as shown by the arrangement of buds and leaf-scars in two longitudinal rows, so that the third bud is directly over the first [— 143.]
142b. Leaves and leaf-scars not 2-ranked [— 146.]
143a. Bundle-scars three in each leaf-scar [— 144.]
143b. Bundle-scars several in each leaf-scar[2b, in URTICACEAE], p. 23.
144a. Leaf-buds with only 1-3 visible bud-scales[10, in BETULACEAE], p. 22.
144b. Leaf-buds with more than 3 visible scales [— 145.]
145a. Bark of the branches smooth and dark gray, the larger stems fluted with projecting longitudinal ridges[1b, in BETULACEAE], p. 21.
145b. Branches without projecting ridges[4, in BETULACEAE], p. 22.
146a. Pith 3-angled[8, in BETULACEAE], p. 22.
146b. Pith 5-angled[13b, in FAGACEAE], p. 23.
146c. Pith cylindrical [— 147.]
147a. Visible outer bud-scales 2 or more [— 148.]
147b. Buds with a single visible outer scale[13, in SALICACEAE], p. 20.
148a. Bundle-scars 3 in each leaf-scar[MYRICACEAE], p. 20.
148b. Bundle-scars more than 3 in each leaf-scar[2b, in URTICACEAE], p. 23.
149a. Flowers dark red-purple, about 3 cm. wide[ANONACEAE], p. 40.
149b. Flowers bright pink, irregular, about 1 cm. wide[3a, in LEGUMINOSAE], p. 58.
149c. Flowers white, with 5 conspicuous petals [— 150.]
149d. Flowers greenish or yellowish, small, inconspicuous [— 152.]
150a. Ovary 1, superior, i. e., in the center of the flower and not attached to surrounding parts[36, in ROSACEAE], p. 54.
150b. Ovary inferior, appearing as a swelling below the calyx at the apex of the pedicel [— 151.]
151a. Flowers in racemes or solitary[42b, in ROSACEAE], p. 55.
151b. Flowers in flattened or rounded branching clusters[42a, in ROSACEAE], p. 55.
152a. Stems thorny[1a, in RUTACEAE], p. 65.
152b. Stems not thorny [— 153.]
153a. Bark pleasantly aromatic when crushed; perianth with 6 parts [— 154.]
153b. Bark not pleasantly aromatic; perianth with 4 short lobes[THYMELAEACEAE], p. 77.
154a. Flowers in sessile lateral clusters[1a, in LAURACEAE], p. 41.
154b. Flowers in peduncled terminal clusters[1b, in LAURACEAE], p. 41.
— 155—
155a. Leaves narrow, needle-like or scale-like, mostly evergreen [— 54.]
155b. Leaves broader, flat or rolled, but not needle-like or scale-like — 156.
156a. Twining or climbing vines [— 56.]
156b. Not twining or climbing [— 157.]
157a. Leaves opposite [— 158.]
157b. Leaves alternate [— 165.]
158a. Leaves compound [— 68.]
158b. Leaves simple [— 159.]
159a. Leaves broad, palmately lobed [— 160.]
159b. Leaves not palmately lobed [— 161.]
160a. Flowers greenish-yellow, in racemes or panicles[2a, in ACERACEAE], p. 70.
160b. Flowers white, in rounded or flattened clusters[22a, in CAPRIFOLIACEAE], p. 111.
161a. Flowers in close clusters, subtended by four large white petal-like bracts[4b, in CORNACEAE], p. 83.
161b. Flowers small, white, in dense spherical heads[1a, in RUBIACEAE], p. 108.
161c. Flowers not in dense heads, and not subtended by petal-like bracts [— 162.]
162a. Petals separate from each other [— 163.]
162b. Petals united with each other [— 164.]
163a. Flowers dark purple-red[1b, in CELASTRACEAE]. p. 69.
163b. Flowers bright yellow[1a, in HYPERICACEAE], p. 73.
163c. Flowers pink-purple; aquatic shrubs[1a, in LYTHRACEAE], p. 77.
163d. Flowers white[5, in CORNACEAE], p. 83.
163e. Flowers minute, greenish; twigs usually thorny[1b, in RHAMNACEAE], p. 71.
163f. Flowers small, yellowish; leaves silvery beneath[ELAEAGNACEAE], p. 77.
164a. Stamens 2[1a, in OLEACEAE], p. 88.
164b. Stamens 4 or 5[11, in CAPRIFOLIACEAE], p. 110.
164c. Stamens 10[18a, in ERICACEAE], p. 85.
165a. Leaves once-compound [— 166.]
165b. Leaves simple [— 172.]
165c. Leaves twice- or thrice-compound[4a, in ARALIACEAE], p. 80.
166a. Flowers small, greenish or greenish-yellow [— 167.]
166b. Flowers conspicuous, white, or brightly colored [— 170.]
167a. Stems thorny[1a, in RUTACEAE], p. 65.
167b. Stems not thorny [— 168.]
168a. Leaflets 3, entire or minutely toothed[1b, in RUTACEAE], p. 65.
168b. Leaflets 3, conspicuously toothed[1b, in ANACARDIACEAE], p. 68.
168c. Leaflets more than 3 [— 169.]
169a. Leaflets entire except for 1-4 large glandular teeth near their base[SIMARUBACEAE], p. 65.
169b. Leaflets entire, or toothed for their entire length[ANACARDIACEAE], p. 68.
170a. Flowers with a single bright-blue petal[8a, in LEGUMINOSAE], p. 58.
170b. Flowers with several petals [— 171.]
171a. Flowers regular[3, in ROSACEAE], p. 51.
171b. Flowers irregular, the upper petal the largest[4, in LEGUMINOSAE], p. 58.
172a. Leaves minute, scale-like, appressed[2a, in CISTACEAE], p. 74.
172b. Leaves 3-10 mm. long, spreading, completely rolled into a tube[EMPETRACEAE], p. 68.
172c. Leaves normal in shape, green in color [— 173.]
173a. Leaves evergreen, as shown by their presence on the older parts of the stem[4b, in ERICACEAE], p. 84.
173b. Leaves deciduous [— 174.]
174a. Flowers in catkins, without petal-like parts [— 142.]
174b. Flowers not in catkins, either with or without petal-like parts [— 175.]
175a. Flowers small, inconspicuous, yellowish or greenish in color [— 176.]
175b. Flowers white or colored, with conspicuous petals [— 180.]
176a. Leaves broad and palmately lobed; stem thorny[1a, in ARALIACEAE], p. 80.
176b. Leaves entire, toothed, or with 2-3 entire lobes; stem not thorny [— 177.]
177a. Flowers in small axillary clusters; foliage not spicy-aromatic [— 178.]
177b. Flowers in clusters terminating last year's twigs; foliage spicy-aromatic[1b, in LAURACEAE], p. 41.
178a. Petals none; sepals present[2b, in RHAMNACEAE], p. 71.
178b. Petals present but small [— 179.]
179a. A stamen in front of each petal[2a, in RHAMNACEAE], p. 71.
179b. A stamen between each two petals[AQUIFOLIACEAE], p. 69.
180a. Petals united with each other; stamens 8-10[24, in ERICACEAE], p. 86.
180b. Petals separate from each other [— 181.]
181a. Petals 4 [— 182.]
181b. Petals 5 [— 183.]
181c. Petal-like sepals 6; real petals none; foliage spicy-aromatic[1b, in LAURACEAE], p. 41.
181d. Petals 6; sepals also present [— 187.]
182a. Flowers in late spring or early summer[2a, in CORNACEAE], p. 83.
182b. Flowers in autumn[HAMAMELIDACEAE], p. 51.
183a. Corolla irregular, the upper petal largest[3b, in LEGUMINOSAE], p. 58.
183b. Corolla regular, all petals alike in size and shape [— 184.]
184a. Stamens 5 [— 185.]
184b. Stamens 10 or more[24, in ROSACEAE], p. 53.
185a. Flowers in loose racemes or axillary clusters[2, in SAXIFRAGACEAE], p. 49.
185b. Flowers in branching clusters [— 186.]
186a. Leaves palmately lobed; stem thorny[1a, in ARALIACEAE], p. 80.
186b. Leaves not lobed; stem not thorny[1b, in RHAMNACEAE], p. 71.
187a. Flowers dark red-purple[ANONACEAE], p. 40.
187b. Flowers yellow[2a, in BERBERIDACEAE], p. 40.

GROUP 2, UNUSUAL PLANTS

1a. Small brown leafless plants, growing as parasites on the tamarack or black spruce[LORANTHACEAE], p. 25.
1b. Aquatic plants, with all or most of the leaves submerged, or leafless [— 2.]
1c. Aquatic plants, with the leaves or the whole plant floating on or near the surface [— 20.]
1d. Terrestrial or marsh plants, without floating or submerged leaves [— 29.]
2a. Submerged aquatics, without leaves [— 3.]
2b. Submerged aquatics, with the leaves linear or dissected [— 4.]
3a. Flowers showy, yellow or purple[LENTIBULARIACEAE], p. 105.
3b. Flowers small and inconspicuous, sessile, purplish or greenish[3a, in HALORAGIDACEAE], p. 79.
4a. Leaves linear or lanceolate, not lobed or dissected [— 5.]
4b. Leaves more or less lobed or dissected [— 13.]
5a. Leaves all basal [— 6.]
5b. Stem-leaves present [— 7.]
6a. Flowers blue, 1 cm. long or more; leaves cylindrical, blunt, hollow, partitioned lengthwise[1a, in LOBELIACEAE], p. 113.
6b. Flowers yellow; leaves minute[LENTIBULARIACEAE], p. 105.
6c. Flowers white, in clusters; leaves linear-lanceolate, acute, not hollow[1b, in ALISMACEAE], p. 3.
6d. Flowers greenish, solitary at the end of elongated peduncles; leaves very long and ribbon-like, flat or trough-shape[1a, in HYDROCHARITACEAE], p. 3.
6e. Flowers minute, whitish or lead-color, in heads[ERIOCAULACEAE], p. 9.
7a. Leaves alternate [— 8.]
7b. Leaves opposite [— 10.]
7c. Leaves whorled [— 12.]
8a. Leaves with thin sheathing stipules[1b, in NAJADACEAE], p. 2.
8b. Leaves without stipules [— 9.]
9a. Flowers greenish, in a head[SPARGANIACEAE], p. 2.
9b. Flowers pale yellow[1b, in PONTEDERIACEAE], p. 10.
10a. Leaves serrate[2b, in NAJADACEAE], p. 2.
10b. Leaves entire [— 11.]
11a. Leaves 2 cm. long or less[CALLITRICHACEAE], p. 68.
11b. Leaves thread-like, 2-8 cm. long[2a, in NAJADACEAE], p. 2.
11c. Leaves linear to elliptical, more than 2 cm. long[1b, in NAJADACEAE], p. 2.
12a. Leaves in whorls of 3, abruptly widened at the base[2b, in NAJADACEAE], p. 2.
12b. Leaves in whorls of 3, widest near the middle[1b, in HYDROCHARITACEAE], p. 3.
12c. Stems straight and erect, at leaves the flowers emerged; leaves in whorls of 4 or more[2a, in HALORAGIDACEAE], p. 79.
13a. Leaves with numerous small bladders attached, each bladder 1-3 mm. long[LENTIBULARIACEAE], p. 105.
13b. Leaves without bladders [— 14.]
14a. Leaves alternate [— 15.]
14b. Leaves opposite or whorled [— 18.]
15a. Delicate and rare plants growing attached to stones in running water[PODOSTEMACEAE], p. 48.
15b. Plants 2 dm. high or more, with roots in mud or sand [— 16.]
16a. Leaves once-pinnate [— 17.]
16b. Leaves 2-3 times pinnate[15b, in UMBELLIFERAE], p. 81.
16c. Leaves palmately dissected[1b, in RANUNCULACEAE], p. 35.
17a. Taste peppery or mustardy[34, in CRUCIFERAE], p. 45.
17b. Taste not peppery or mustardy[1a, in HALORAGIDACEAE], p. 79.
18a. Leaves pinnately compound[3b, in HALORAGIDACEAE], p. 79.
18b. Leaves palmately compound [— 19.]
19a. Leaves opposite or in whorls of four[119a, in COMPOSITAE], p. 123.
19b. Leaves in whorls of 5-12[CERATOPHYLLACEAE], p. 34.
20a. Plants small, flattened, rounded or ovate, without distinction of stem and leaf; the whole plant floating on or near the surface[LEMNACEAE], p. 9.
20b. Plant attached to the soil, with differentiated stem and leaves [— 21.]
21a. Leaves on long slender stalks, which bear also a cluster of slender tubers near the leaf-base; leaves heart-shape[1b, in GENTIANACEAE], p. 88.
21b. Leaf-stalks without a cluster of tubers [— 22.]
22a. Leaves all basal [— 23.]
22b. Stem-leaves present [— 24.]
23a. Leaves parallel-veined[1b, in ALISMACEAE], p. 3.
23b. Leaves net-veined[1b, in NYMPHAEACEAE], p. 35.
24a. Leaves opposite or whorled [— 25.]
24b. Leaves alternate [— 26.]
25a. Leaves less than 2 cm. long[CALLITRICHACEAE], p. 68.
25b. Leaves more than 2 cm. long[1b, in NAJADACEAE], p. 2.
26a. Leaves attached by the center to the stalk[2b, in NYMPHAEACEAE], p. 35.
26b. Leaves attached by the margin [— 27.]
27a. Leaves parallel-veined [— 28.]
27b. Leaves net-veined, with a single mid-vein; lanceolate or elliptical in outline[29b, in POLYGONACEAE], p. 28.
28a. Leaves not over 2 dm. long[1b, in NAJADACEAE], p. 2.
28b. Leaves very long and grass-like[14a, in GRAMINEAE], p. 5.
29a. Brown, yellow, or white plants, without green color [— 30.]
29b. Plants with normal green color, at least in some parts [— 33.]
30a. Stemless and leafless plants, consisting of flowers only and partly underground[4a, in ARACEAE], p. 8.
30b. Stems climbing on other plants[1b, in CONVOLVULACEAE], p. 91.
30c. Stem and flower-stalks erect, not climbing [— 31.]
31a. Corolla regular; stamens 6-12[1a, in ERICACEAE], p. 84.
31b. Corolla irregular [— 32.]
32a. Sepals and petals each 3; flowers in simple racemes[5a, in ORCHIDACEAE], p. 16.
32b. Sepals 5; corolla of united petals[OROBANCHACEAE], p. 106.
33a. Stem thick and fleshy, leafless, thorny[CACTACEAE], p. 77.
33b. Stem not thorny [— 34.]
34a. Leaves none [— 35.]
34b. Leaves reduced to small scales [— 40.]
34c. Leaves thick and fleshy [— 44.]
34d. Leaves hollow [— 45.]
34e. Leaves small, all basal, bearing large glandular hairs on the upper surface[DROSERACEAE], p. 48.
35a. Stem none, the flowers appearing at or partially beneath the surface of the soil[4a, in ARACEAE], p. 8.
35b. Stem present [— 36.]
36a. Stem freely branched[2a, in LILIACEAE], p. 10.
36b. Stem unbranched, except possibly in the flower-clusters [— 37.]
37a. Flowers greenish or brownish, without obvious colored petals [— 38.]
37b. Flowers with conspicuous white or colored petals [— 39.]
38a. Each flower with 6 small chaffy petals[4, in JUNCACEAE], p. 10.
38b. Petals none; each flower in the axil of a single chaffy bract[2a, in CYPERACEAE], p. 7.
39a. Flowers regular[34a, in LILIACEAE], p. 11.
39b. Flowers irregular[10a, in ORCHIDACEAE], p. 16.
40a. Stem erect, unbranched or with one or two branches only [— 41.]
40b. Stem freely branched [— 42.]
41a. Plants of moist soil, with opposite scales; corolla regular, with 4 petal-like lobes[1a, in GENTIANACEAE], p. 88.
41b. Swamp plants, with a few alternate scales; corolla irregular[LENTIBULARIACEAE], p. 105.
42a. Leaves numerous and close, concealing the stem[2a, in CISTACEAE], p. 74
42b. Leaves spreading, not concealing the stem [— 43.]
43a. Leaf-scales in small clusters; flowers greenish, with 6 petals[2a, in LILIACEAE], p. 10.
43b. Leaf-scales distinctly opposite; petals 5, yellow[7a, in HYPERICACEAE], p. 74.
44a. Sepals 2[3, in PORTULACACEAE], p. 34.
44b. Sepals 4 or 5[CRASSULACEAE], p. 48.
45a. Leaves pitcher-shape, open at the top[SARRACENIACEAE], p. 48.
45b. Leaves tubular, closed at the end[37b, in LILIACEAE], p. 13.

GROUP 3, MONOCOTYLEDONES

1a. Twining plants, with flowers in panicles or racemes[DIOSCOREACEAE], p. 14.
1b. Plants with milky juice[13a, in COMPOSITAE], p. 115.
1c. Plants not twining (some climb by tendrils) and not with milky juice. [— 2.]
2a. Flowers in close spikes or heads, surrounded or subtended by a green or colored bract, the whole resembling a single flower; petals minute or wanting; leaves broad, not grass-like, linear, or sword-shape[ARACEAE], p. 8.
2b. Plants with narrow, linear, grass-like, or sword-shape leaves (a few species of Carex have broader, lanceolate to ovate leaves); flowers greenish, yellowish, or brownish, never brightly colored, and frequently dry or chaffy in texture; perianth small or wanting; individual flowers inconspicuous in size, but sometimes grouped into conspicuous clusters [— 3.]
2c. Plants with leaves of various widths, but the flowers petaloid, i. e., with a white or colored, more or less conspicuous perianth, and never chaffy in texture. In a few cases the flowers are greenish, but the size and conspicuousness of the perianth identifies them in this class [— 9.]
3a. Flowers in the axils of dry, membranous or chaffy scales, which are regularly arranged into spikes or spikelets of uniform size and structure, which are variously grouped or clustered; fruit an achene; grasses and sedges, with joined stems and sheathing leaves, or leafless and the stems not jointed [— 4.]
3b. Flowers not subtended individually by dry, membranous, or chaffy scales, and otherwise not agreeing with 3a [— 5.]
4a. Leaf-sheaths split on the side opposite the leaf; leaves usually 2-ranked, i. e., in 2 longitudinal rows with the third leaf above the first; stems rounded or flat, never triangular, usually hollow[GRAMINEAE], p. 4.
4b. Leaf-sheaths closed into a continuous tube; leaves usually 3-ranked; stems frequently triangular, usually solid[CYPERACEAE], p. 7.
5a. Flowers in dense spikes [— 6.]
5b. Flowers in heads, racemes, or panicles [— 7.]
6a. Spike terminal, with pistillate flowers at the base and staminate ones at the apex[TYPHACEAE], p. 2.
6b. Spike short, apparently lateral, near the apex of the stem[3a, in ARACEAE], p. 8.
7a. Flowers in globose heads which are arranged in spikes, the lowest heads pistillate, the upper staminate; ovary 1-celled[SPARGANIACEAE], p. 2.
7b. Flowers in globose woolly heads terminating leafless unbranched stalks[ERIOCAULACEAE], p. 9.
7c. Flowers in a spike-like raceme; ovaries 3-6, separate or nearly so[JUNCAGINACEAE], p. 3.
7d. Flowers in heads or panicles, all perfect, not woolly, with one ovary [— 8.]
8a. Leaves less than 1 cm. wide, or none; divisions of the perianth 6[JUNCACEAE], p. 10.
8b. Leaves 2 cm. wide or more; petals 5[2a, in UMBELLIFERAE], p. 80.
9a. Flowers regular, with all the petals of approximately the same size and shape [— 10.]
9b. Flowers irregular, with the petals of each flower not of the same size or shape [— 22.]
10a. Ovaries 3 or more, separate or barely united with each other at the base [— 11.]
10b. Ovary one in each flower [— 12.]
11a. Ovaries 3-6 in number; flowers in spikes or racemes; leaves linear[JUNCAGINACEAE], p. 3.
11b. Ovaries more than 6[ALISMACEAE], p. 3.
12a. Flowers or flower-clusters lateral, axillary or apparently so [— 13.]
12b. Flowers or flower-clusters terminal or on leafless stalks [— 14.]
13a. Leaves minute and scale-like; flowers greenish-yellow[2a, in LILIACEAE], p. 10.
13b. Leaves linear, grass-like[3b, in IRIDACEAE], p. 13.
13c. Leaves lanceolate or broader, not grass-like or scale-like[2b, in LILIACEAE], p. 10.
14a. Divisions of the perianth 5-12 cm. long [— 15.]
14b. Divisions of the perianth less than 5 cm. long [— 16.]
15a. Flowers blue, or blue marked with yellow[1a, in IRIDACEAE], p. 15.
15b. Flowers not blue[12a, in LILIACEAE], p. 11.
16a. Flowers solitary [— 17.]
16b. Flowers 2 or more, in some kind of a cluster [— 18.]
17a. Leaves 2, broadly heart-shape, basal, on long stalks[1b, in ARISTOLOCHIACEAE], p. 25.
17b. Leaves not heart-shape 20,[20, in LILIACEAE], p. 12.
18a. Divisions of the perianth (4 to 6) all essentially alike [— 19.]
18b. Perianth differentiated into sepals and 2 or 3 colored petals [— 21.]
19a. Flowers in umbels [— 20.]
19b. Flowers in dense round heads; petals 5[2a, in UMBELLIFERAE], p. 80.
19c. Flowers in spikes, racemes, or panicles[38, in LILIACEAE], p. 13.
20a. Ovary inferior, appearing below the perianth as a swelling at the apex of the stalk; flowers bright yellow; leaves linear[AMARYLLIDACEAE], p. 14.
20b. Ovary inferior; flowers blue or white, terminating a flattened winged leafless flower-stalk[3a, in IRIDACEAE], p. 15.
20c. Ovary superior, i. e., in the center of the flower and separate from the perianth[31, in LILIACEAE], p. 13.
21a. Flowers in dense heads, yellow, 1 cm. wide or smaller[XYRIDACEAE], p. 9.
21b. Flowers in umbels, blue or white, 2 cm. wide or larger[COMMELINACEAE], p. 9.
22a. Flowers blue; ovary superior (defined under [20c]); stamens distinct from the other parts of the flower [— 23.]
22b. Ovary inferior (defined under [20a]); floral structure complex; stamens attached to other parts of the flower and not resembling ordinary stamens in form or structure[ORCHIDACEAE], p. 15.
23a. Leaves triangular-heart-shape at base; marsh plants[1a, in PONTEDERIACEAE], p. 10.
23b. Leaves not heart-shape at base[COMMELINACEAE], p. 9.

GROUP 4, DICOTYLEDONES

1a. Foliage leaves all or principally basal; flower-stalk either completely leafless, or bearing a single pair of opposite leaves only. Bracts and scale-leaves are not considered foliage leaves [— 2.]
1b. Stem-leaves present on the stem, either one or more in number, and not limited to a single opposite pair [— 3.]
2a. Leaves compound [— 7.]
2b. Leaves simple [— 18.]
3a. Stem-leaves all or chiefly opposite or whorled (the bracts of the flower clusters may be alternate) [— 4.]
3b. Stem-leaves all or chiefly alternate [— 5.]
4a. Flowers small and inconspicuous, the perianth none or greenish or chaffy, and never petal-like in appearance [— 50.]
4b. Flowers with a white or colored petal-like perianth [— 66.]
5a. Flowers small and inconspicuous, without any white or colored petal-like perianth [— 118.]
5b. Flowers large or small, but with a white or colored petal-like perianth [— 6.]
6a. Flowers small, not exceeding 3 mm. in length or breadth [— 144.]
6b. Flowers larger, more than 3 mm. in length or breadth [— 166.]
— 7—
7a. Leaves twice to three times compound or dissected [— 8.]
7b. Leaves once-compound [— 11.]
8a. Flowers in racemes[2b, in FUMARIACEAE], p. 41.
8b. Flowers in umbels [— 9.]
9a. Flowers about 3 mm. wide, white or greenish-white [— 10.]
9b. Flowers 10-20 mm. wide, conspicuous[45b, in RANUNCULACEAE], p. 39.
10a. Leaflets 5-15 cm. long[5b, in ARALIACEAE], p. 80.
10b. Leaflets not over 2 cm. long[16a, in UMBELLIFERAE], p. 81.
11a. Leaflets 2[3a, in BERBERIDACEAE], p. 40.
11b. Leaflets three or more [— 12.]
12a. Leaflets entire or very finely toothed [— 13.]
12b. Leaflets coarsely toothed or lobed [— 15.]
13a. Flowers irregular, in dense head-like umbels[37a, in LEGUMINOSAE], p. 61.
13b. Flowers consisting of a greenish or purplish bract wholly or partly enclosing a fleshy spike[2, in ARACEAE], p. 8.
13c. Flowers regular, solitary or in loose clusters [— 14.]
14a. Leaflets reverse heart-shape, not over 2 cm. long[OXALIDACEAE], p. 64.
14b. Leaflets 4-10 cm. long[1c, in GENTIANACEAE], p. 88.
15a. Flowers with colored or white petals and green or colored sepals [— 16.]
15b. Flowers with one kind of perianth only (calyx), with broad and petal-like parts[32, in RANUNCULACEAE], p. 38.
15c. Flowers with white petal-like sepals and small inconspicuous petals[38b, in RANUNCULACEAE], p. 39.
16a. Petals and sepals each 4[31, in CRUCIFERAE], p. 44.
16b. Petals and sepals each 5 or more [— 17.]
17a. Leaves with stipules[ROSACEAE], p. 51.
17b. Leaves without stipules[23b, in RANUNCULACEAE], p. 37.
— 18—
18a. Stem-leaves a single opposite pair (basal leaves may also be present) [— 19.]
18b. Stem-leaves none [— 23.]
19a. Leaves entire [— 20.]
19b. Leaves toothed or lobed [— 21.]
20a. Flowers solitary; leaves broadly kidney-shape[ARISTOLOCHIACEAE], p. 25.
20b. Flowers in racemes; leaves linear or lanceolate[PORTULACACEAE], p. 34.
21a. Flowers in racemes; petals deeply toothed[23b, in SAXIFRAGACEAE], p. 51.
21b. Flowers solitary or few in a cluster; petals entire or nearly so [— 22.]
22a. Petals 5[GERANIACEAE], p. 64.
22b. Petals 6 or more[2b, in BERBERIDACEAE], p.40.
23a. Flowers or flower-clusters sessile, at or partly beneath the surface of the ground[4a, in ARACEAE], p. 8.
23b. Flowers or flower-heads solitary at the ends of the flower-stalks [— 24.]
23b. Flowers or flower-heads numerous or several on each flower-stalk [— 38.]
24a. Flowers yellow [— 25.]
24b. Flowers not yellow [— 29.]
25a. Juice milky[16, in COMPOSITAE], p. 115.
25b. Juice not milky [— 26.]
26a. Aquatic or mud plants, with large entire leaves 1-4 dm. wide[NYMPHAEACEAE], p. 35.
26b. Land plants, with smaller or lobed leaves [— 27.]
27a. Flower-stalk scaly[110, in COMPOSITAE], p. 122.
27b. Flower-stalk bare or with 1 to 2 minute bracts [— 28.]
28a. Flowers regular[10, in RANUNCULACEAE], p. 36.
28b. Flowers irregular, with a spur[3a, in VIOLACEAE], p. 75.
29a. Flowers obviously irregular, with a spur [— 30.]
29b. Flowers regular or nearly so, without a spur [— 31.]
30a. Leaves sessile or nearly so; stamens 2[LENTIBULARIACEAE], p. 105.
30b. Leaves petioled; stamens 5[VIOLACEAE], p. 75.
31a. Flowers 3 mm. wide or smaller; leaves thread-like[16a, in SCROPHULARIACEAE], p. 103.
31b. Flowers 6 mm. wide or larger [— 32.]
32a. Ovary 1 [— 33.]
32b. Ovaries numerous [— 37.]
33a. Leaves lobed or cleft [— 34.]
33b. Leaves entire or toothed [— 35.]
34a. Leaves deeply 2-cleft; stamens 8[3a, in BERBERIDACEAE], p. 40.
34b. Leaf 1, palmately lobed; stamens numerous[1a, in PAPAVERACEAE], p. 41.
35a. Flowers dull red[ARISTOLOCHIACEAE], p. 25.
35b. Flowers white or pinkish [— 36.]
36a. Leaves entire; stamens with good anthers 5[13, in SAXIFRAGACEAE], p. 50.
36b. Leaves minutely toothed; stamens 8-10[14a, in ERICACEAE], p. 85.
37a. Leaves lobed or divided[RANUNCULACEAE], p. 35.
37b. Leaves crenate or toothed[64a, in ROSACEAE], p. 56.
— 38—
38a. Flowers of the composite type, with several or many small flowerets closely aggregated into a dense head surrounded by a calyx-like involucre of small bracts[10, in COMPOSITAE]. p. 114.
38b. Flowers separate; variously clustered, but never crowded into involucred heads [— 39.]
39a. Flowers in dense close spikes [— 40.]
39b. Flowers in open loose clusters [— 42.]
40a. Flower-stalk leafless below the spike[PLANTAGINACEAE], p. 107.
40b. Flower-stalk with several bracts [— 41.]
41a. Leaves entire[9c, in ORCHIDACEAE], p. 16.
41b. Leaves toothed[6a, in SCROPHULARIACEAE], p. 102.
42a. Flowers in umbels [— 43.]
42b. Flowers in racemes, panicles, flat-topped clusters, or merely 1 or 2 [— 45.]
43a. Leaves almost round, peltate, palmately veined[3a, in UMBELLIFERAE], p. 80.
43b. Leaves at least twice as long as broad, with a single mid-vein [— 44.]
44a. Stamens 5[PRIMULACEAE], p. 87.
44b. Stamens 10[15, in ERICACEAE], p. 85.
45a. Leaves cylindrical, hollow, obtuse.[1a, in LOBELIACEAE], p. 113.
45b. Leaves beset on the upper side with long glandular hairs; bog plant with flowers in racemes[DROSERACEAE], p. 48.
45c. Leaves flat, pubescent or smooth, but not with long glandular hairs [— 46.]
46a. Sepals and petals each 4[53, in CRUCIFERAE], p. 46.
46b. Sepals and petals each 5 [— 47.]
46c. Sepals 6; petals none; flowers minute, green; leaves frequently lobed at the base[4, in POLYGONACEAE], p. 25.
47a. Petals united with each other in an irregular corolla[LENTIBULARIACEAE], p. 105.
47b. Petals separate from each other [— 48.]
48a. Stamens 10; style 1[ERICACEAE], p. 84.
48b. Stamens 5 or 10; styles 2[SAXIFRAGACEAE], p. 49.
48c. Stamens and pistils each very numerous [— 49.]
49a. Flowers white[64a, in ROSACEAE], p. 56.
49b. Flowers yellow[13a, in RANUNCULACEAE], p. 36.
— 50—
50a. Leaves compound or deeply lobed [— 51.]
50b. Leaves entire or toothed [— 54.]
51a. Flowers in axillary racemes, spikes, or panicles[URTICACEAE], p. 23.
51b. Flowers terminal, or in terminal clusters [— 52.]
52a. Flowers in umbels; leaves palmately compound[ARALIACEAE], p. 80.
52b. Flowers in racemes or spikes, or solitary [— 53.]
53a. Leaves deeply pinnatifid; swamp plants with flowers in spikes or solitary[HALORAGIDACEAE], p. 79.
53b. Leaves lobed, or irregularly pinnately cut or dissected; weedy plants with flowers in racemes[2, in COMPOSITAE], p. 114.
54a. Juice milky[3, in EUPHORBIACEAE], p. 67.
54b. Juice not milky or colored [— 55.]
55a. Leaves whorled [— 56.]
55b. Leaves all opposite [— 58.]
56a. Aquatic or mud plants with erect stems[2a, in HALORAGIDACEAE], p. 79.
56b. Prostrate weedy terrestrial plants[AIZOACEAE], p. 31.
56c. Erect or ascending terrestrial plants [— 57.]
57a. Leaves more than 2.5 cm. long[4a, in CORNACEAE], p. 83.
57b. Leaves 2 cm. long or less[3a, in PRIMULACEAE], p. 87.
58a. Flowers in terminal or axillary spikes, racemes, or other clusters [— 59.]
58b. Flowers solitary or few in the axils of the leaves [— 61.]
59a. Leaves less than 5 mm. long[1a, in GENTIANACEAE], p. 88.
59b. Leaves more than 2 cm. long [— 60.]
60a. Inflorescence chiefly terminal, panicled[2, in COMPOSITAE], p. 114.
60b. Inflorescence chiefly axillary[URTICACEAE], p. 23.
61a. Flowers on long pedicels[2, in CARYOPHYLLACEAE], p. 31.
61b. Flowers on short pedicels or sessile [— 62.]
62a. Stem erect, repeatedly branched; leaves linear to oblong[ILLECEBRACEAE], p. 31.
62b. Stem decumbent or prostrate [— 63.]
63a. Leaves round, ovate, or kidney-shape, rounded at the base, crenate or lobed[12a, in SAXIFRAGACEAE], p. 50.
63b. Leaves of a narrower shape, entire, tapering toward the base [— 64.]
64a. Principal leaves 2-3 cm. long[1a, in ONAGRACEAE], p. 78.
64b. Principal leaves 1 cm. long or less [— 65.]
65a. Petals present[ELATINACEAE], p. 74.
65b. Petals none[CALLITRICHACEAE], p. 68.
— 66—
66a. Plants of the composite type, with several or many small flowerets closely aggregated into a dense head surrounded or subtended by a calyx-like involucre of small bracts [— 67.]
66b. Flowers solitary or variously clustered, but not in involucred heads [— 70.]
67a. Involucre of 4 conspicuous white bracts, much larger than the small flower-cluster[4a, in CORNACEAE], p. 83.
67b. Involucral bracts green or somewhat colored [— 68.]
68a. Stem more or less prickly[DIPSACACEAE], p. 112.
68b. Stem and leaves not prickly [— 69.]
69a. Stem square; foliage aromatic when crushed[LABIATAE], p. 95.
69b. Stem not square; foliage not with the odor of mint[COMPOSITAE], p. 113.
70a. The conspicuous portion of the perianth[1] composed of separate parts [— 71.]
70b. The conspicuous portion of the perianth[1] composed of united parts [— 97.]
71a. Stem-leaves compound, or cleft to the very base [— 72.]
71b. Stem-leaves simple [— 78.]
72a. Stamens more than 10 in each flower [— 73.]
72b. Stamens 5-10 in each flower [— 75.]
73a. Ovary 1 in each flower[2a, in PAPAVERACEAE], p. 41.
73b. Ovaries several in each flower [— 74.]
74a. Leaves pinnately compound[68a, in ROSACEAE], p. 57.
74b. Leaves palmately compound[RANUNCULACEAE], p. 35.
75a. Stamens 6[31, in CRUCIFERAE], p. 44.
75b. Stamens 5 or 10 [— 76.]
76a. Leaflets reverse heart-shape; flowers yellow[OXALIDACEAE], p. 64.
76b. Leaflets not reverse heart-shape; flowers white, greenish, or pink [— 77.]
77a. Flowers greenish or white, about 2 mm. broad[ARALIACEAE], p. 80.
77b. Flowers 5 mm. broad or larger[GERANIACEAE], p. 64.
78a. Juice milky [— 79.]
78b. Juice not milky [— 80.]
79a. A 3-lobed ovary with 3 short styles visible in some of the flowers[EUPHORBIACEAE], p. 66.
79b. Ovaries 2 in the center of each flower (sometimes concealed by other organs); sepals and petals each 5 [— 104.]
80a. Perianth with one circle of parts only [— 81.]
80b. Each flower with both calyx and corolla [— 82.]
81a. Stem prostrate; flowers only 2 mm. broad[AIZOACEAE], p. 31.
81b. Stem erect; flowers at least 20 mm. wide[4a, in CORNACEAE], p. 83.
82a. Petals 2 or 4 [— 83.]
82b. Petals 3[22, in LILIACEAE], p. 12.
82c. Petals 5 or 6 [— 84.]
83a. Leaves with 3-5 principal veins[MELASTOMACEAE], p. 77.
83b. Leaves with 1 principal mid-vein[ONAGRACEAE], p. 78.
84a. Leaves palmately lobed [— 85.]
84b. Leaves entire or toothed, or with 1-2 small lobes near the base only [— 86.]
85a. Petals entire or notched at the end[GERANIACEAE], p. 64.
85b. Petals conspicuously fringed[23b, in SAXIFRAGACEAE], p. 51.
86a. Ovary 1 [— 87.]
86b. Ovaries 2, surrounded and concealed by other organs[ASCLEPIADACEAE], p. 90.
86c. Ovaries 4-5[2b, in CRASSULACEAE], p. 48.
87a. Leaves dotted with translucent dots (easily seen when the leaf is held to the light)[HYPERICACEAE], p. 73.
87b. Leaves not dotted with translucent dots [— 88.]
88a. Leaves only 1-3 mm. long, closely appressed and concealing the stem[2a, in CISTACEAE], p. 74.
88b. Leaves larger, not concealing the stem [— 89.]
89a. Style 1 or none [— 90.]
89b. Styles 2 to 7 [— 94.]
90a. Stamens 5 [— 91.]
90b. Stamens 10 [— 92.]
90c. Stamens neither 5 nor 10 [— 93.]
91a. Flowers blue, sessile in terminal spikes with leaf-like bracts[LYTHRACEAE], p. 77.
91b. Flowers not in terminal bracted spikes[PRIMULACEAE], p. 87.
92a. Leaves entire[LYTHRACEAE], p. 77.
92b. Leaves toothed or crenate[ERICACEAE], p. 84.
93a. Flowers irregular; petals 3[POLYGALACEAE], p. 65.
93b. Flowers regular; petals 5 or more[LYTHRACEAE], p. 77.
94a. Sepals 2, partly attached to the ovary[PORTULACACEAE], p. 34.
94b. Sepals 5, free from the ovary [— 95.]
95a. Stamens 5 [— 96.]
95b. Stamens not 5[CARYOPHYLLACEAE], p. 31.
96a. Flowers blue or yellow[LINACEAE], p. 63.
96b. Flowers white or pinkish[CARYOPHYLLACEAE], p. 31.
— 97—
97a. Perianth with but one circle of floral leaves [— 98.]
97b. Perianth consisting of both calyx and corolla [— 101.]
98a. Flowers small, in dense heads subtended by conspicuous bracts [— 99.]
98b. Flowers 2-5, in a colored spreading 5-lobed involucre[NYCTAGINACEAE], p. 31.
98c. Flowers in various sorts of clusters or solitary, but never in heads with a conspicuous involucre [— 100.]
99a. Bracts 4, white and conspicuous; stem not thorny[4a, in CORNACEAE], p. 83.
99b. Bracts green; stem thorny[DIPSACACEAE], p. 112.
100a. Stamens 3[VALERIANACEAE], p. 111.
100b. Stamens 4 or 5[RUBIACEAE], p. 108.
101a. Anthers more numerous than the lobes of the corolla [— 102.]
101b. Anthers just as many as the lobes of the corolla [— 103.]
101c. Anthers fewer than the lobes of the corolla [— 110.]
102a. Leaves simple[POLYGALACEAE], p. 65.
102b. Leaves compound with 3 leaflets[OXALIDACEAE], p. 64.
102c. Leaves finely dissected; stems climbing[2a, in FUMARIACEAE], p. 41.
103a. Ovaries 2 [— 104.]
103b. Ovary 1, but very deeply 4-lobed, with a single style[LABIATAE], p. 95.
103c. Ovary 1, not deeply lobed [— 105.]
104a. Stamens united, surrounding and more or less concealing the ovaries, and not resembling ordinary stamens[ASCLEPIADACEAE], p. 90.
104b. Stamens separate, of ordinary structure[APOCYNACEAE], p. 90.
105a. Ovary inferior, appearing as a swelling below the calyx at the apex of the pedicel [— 106.]
105b. Ovary superior, located in the center of the flower [— 107.]
106a. Corolla 3-4-lobed[RUBIACEAE], p. 108.
106b. Corolla 5-lobed[3b, in CAPRIFOLIACEAE], p. 109.
107a. Leaves toothed or deeply cut[VERBENACEAE], p. 99.
107b. Leaves entire [— 108.]
108a. A stamen in front of the middle of each petal[PRIMULACEAE], p. 87.
108b. Stamens located between the petals or lobes of the corolla, or else so far down in the tubular corolla that their position is not easily ascertained [— 109.]
109a. Corolla salver-form, with a very slender tube, and abruptly spreading lobes[POLEMONIACEAE], p. 92.
109b. Corolla salver-form, with a wide tube and fringed blue petals[GENTIANACEAE], p. 88.
109c. Corolla rotate, funnel-form, or bell-shape[GENTIANACEAE], p. 88.
110a. Ovary deeply 4-lobed, appearing like 4 separate ovaries; style 1[LABIATAE], p. 95.
110b. Ovary not 4-lobed [— 111.]
111a. Stamens 2 [— 112.]
111b. Stamens 3[VALERIANACEAE], p. 111.
111c. Stamens 4 [— 113.]
112a. Flowers in dense heads[1a, in ACANTHACEAE], p. 107.
112b. Flowers solitary or in loose clusters[SCROPHULARIACEAE], p. 101.
113a. Corolla distinctly 2-lipped and irregular [— 114.]
113b. Corolla not distinctly 2-lipped, its 5 lobes all alike or nearly so [— 115.]
114a. Calyx 2-lipped; the upper lip with 3 awl-shape teeth, the lower with 2 short teeth; flowers in slender terminal spikes[PHRYMACEAE], p. 107.
114b. Calyx not obviously 2-lipped, its teeth equal or nearly so[SCROPHULARIACEAE], p. 101.
115a. Flowers sessile or nearly so, in spikes [— 116.]
115b. Flowers in nodding pairs at the top of a slender stalk[3a, in CAPRIFOLIACEAE], p. 109.
115c. Flowers solitary or in clusters; not in spikes or nodding pairs [— 117.]
116a. Corolla not over 1 cm. long[VERBENACEAE], p. 99.
116b. Corolla 1.5 cm. long or more[SCROPHULARIACEAE], p. 101.
117a. Calyx-lobes 15-25 mm. long; flowers blue, 3-5 cm. long; calyx without an obvious tube[2, in ACANTHACEAE], p. 107.
117b. Calyx-lobes united below into an obvious calyx-tube[SCROPHULARIACEAE], p. 101.
— 118—
118a. Leaves deeply lobed, compound, or dissected [— 119.]
118b. Leaves simple and not deeply lobed [— 129.]
119a. Leaves once-pinnately compound or lobed [— 120.]
119b. Leaves once-palmately compound or lobed [— 124.]
119c. Leaves dissected or 2-3 times compound [— 125.]
120a. Leaves merely lobed [— 121.]
120b. Leaves actually compound [— 123.]
121a. Flowers axillary; marsh or swamp plants[HALORAGIDACEAE], p. 79.
121b. Flowers in terminal clusters [— 122.]
122a. Stamens 2-6; taste mustard-like[52b, in CRUCIFERAE], p. 46.
122b. Stamens 10 or more[RESEDACEAE], p. 48.
123a. Leaflets entire[LIMNANTHACEAE], p. 68.
123b. Leaflets serrate[70a, in ROSACEAE], p. 57.
124a. Flowers solitary[31a, in RANUNCULACEAE], p. 38.
124b. Flowers in dense terminal umbels or heads[UMBELLIFERAE], p. 80.
124c. Flowers in terminal racemes[2a, in COMPOSITAE], p. 114.
124d. Flowers in axillary spikes or panicles[9b, in URTICACEAE], p. 24.
125a. Leaves merely dissected, not truly compound with distinct leaflets [— 126.]
125b. Leaves truly compound, with distinct petiolate leaflets [— 127.]
126a. Flowers in axillary clusters[CHENOPODIACEAE], p. 28.
126b. Flowers in terminal clusters[COMPOSITAE], p. 113.
127a. Stamens 5; flowers in umbels [— 128.]
127b. Stamens 6; flowers in small clusters[3b, in BERBERIDACEAE], p. 40.
127c. Stamens many; flowers in racemes or panicles[RANUNCULACEAE], p. 35.
128a. Styles 5[ARALIACEAE], p. 80.
128b. Styles 2[UMBELLIFERAE], p. 80.
129a. Flowers in dense cottony heads; plants more or less white-woolly[79, in COMPOSITAE], p. 120.
129b. Pistillate flowers in an ovoid spiny involucre, ripening into a bur[3a, in COMPOSITAE], p. 114.
129c. Flowers minute, subtended by palmately cleft axillary bracts[1a, in EUPHORBIACEAE], p. 66.
129d. Plants without any of the preceding characters [— 130.]
130a. Plants with milky or colored juice[10, in EUPHORBIACEAE], p. 67.
130b. Plants with tendrils, at least on the upper leaves[4a, in LILIACEAE], p. 11.
130c. Plants of nettle-like character, with stinging hairs[8b, in URTICACEAE], p. 24.
130d. Plants with sheathing stipules, surrounding the stem above the base of each leaf[POLYGONACEAE], p. 25.
130e. Plants with smooth, pale, juicy, almost translucent stems[12a, in URTICACEAE], p. 24.
130f. Plants without any of the preceding structures or habits [— 131.]
131a. Flowers axillary, solitary or in few-flowered clusters [— 132.]
131b. Flowers in terminal, or terminal and axillary clusters [— 138.]
132a. Leaves linear[CHENOPODIACEAE], p. 28.
132b. Leaves of a broader shape than linear [— 133.]
133a. Flower-clusters with bracts as long as or longer than the flowers [— 134.]
133b. Flowers without conspicuous bracts [— 135.]
134a. Leaves broadest below the middle[8a, in URTICACEAE], p. 24.
134b. Leaves broadest above the middle[2, in AMARANTHACEAE], p. 30.
135a. Principal leaves 3 cm. long or more [— 136.]
135b. Principal leaves 2.5 cm. long or less [— 137.]
136a. Flowers nodding in the axils of the leaves[1a, in VIOLACEAE], p. 75.
136b. Flowers erect in the axils[2a, in ONAGRACEAE], p. 78.
137a. Leaves narrowly oblong[1a, in HALORAGIDACEAE], p. 79.
137b. Leaves roundish and somewhat heart-shape[12a, in SAXIFRAGACEAE], p. 50.
138a. Flowers in racemes or simple spikes [— 139.]
138b. Flowers in panicles or other branched clusters [— 141.]
139a. Leaves toothed or lobed[52b, in CRUCIFERAE], p. 46.
139b. Leaves entire [— 140.]
140a. Flowers sessile; leaves heart-shape[PIPERACEAE], p. 19.
140b. Flowers pedicelled; leaves obovate[8b, in PRIMULACEAE], p. 87.
141a. Individual flowers distinct from each other, on pedicels [— 142.]
141b. Individual flowers crowded in close clusters, or separate and sessile [— 143.]
142a. Leaves finely serrate[3b, in CRASSULACEAE], p. 49.
142b. Leaves entire[1b, in CISTACEAE], p. 74.
143a. Flower-clusters mingled with sharp-pointed bracts[AMARANTHACEAE], p. 30.
143b. Flower-clusters without bracts, or (rarely) with bracts which are not sharp-pointed[CHENOPODIACEAE], p. 28.
— 144—
144a. Juice not milky [— 145.]
144b. Juice milky; apparent flowers consisting of a few white or colored petal-like bracts, inclosing a few inconspicuous flowers without petals. In some of them a 3-lobed ovary with 3 styles may be plainly seen
145a. Plants of the composite type, with several or many small flowerets closely aggregated into a dense head subtended by a calyx-like involucre of small bracts [— 146.][EUPHORBIACEAE], p. 66.
145b. Flowers solitary or in clusters, but not in involucred heads [— 147.]
146a. Leaves compound with 3 leaflets; stipules present[LEGUMINOSAE], p. 58.
146b. Stipules none[COMPOSITAE], p. 113.
147a. Leaves compound or deeply lobed [— 148.]
147b. Leaves simple and not deeply lobed [— 154.]
148a. Flowers irregular[LEGUMINOSAE], p. 58.
148b. Flowers regular [— 149.]
149a. Petals 3[LIMNANTHACEAE], p. 68.
149b. Petals 4 [— 150.]
149c. Petals 5 or more [— 151.]
150a. Stamens 4[70a, in ROSACEAE], p. 57.
150b. Stamens 6[CRUCIFERAE], p. 42.
150c. Stamens numerous[43, in RANUNCULACEAE], p. 39.
151a. Flowers in heads or umbels [— 152.]
151b. Flowers in slender spikes or racemes [— 153.]
152a. Styles 2[UMBELLIFERAE], p. 80.
152b. Styles 5[ARALIACEAE], p. 80.
153a. Leaves ternately compound[43, in RANUNCULACEAE], p. 39.
153b. Leaves once-pinnately compound[50b, in ROSACEAE], p. 55.
154a. Flowers irregular [— 155.]
154b. Flowers regular [— 156.]
155a. Stamens 2[40b, in SCROPHULARIACEAE], p. 104.
155b. Stamens 5 or 10[SAXIFRAGACEAE], p. 49.
155c. Stamens 6 or 8[POLYGALACEAE], p. 65.
156a. With sheathing stipules surrounding the stem at the base of each leaf[POLYGONACEAE], p. 24.
156b. Stipules not encircling the stem, or none [— 157.]
157a. Petals 3[CISTACEAE], p. 74.
157b. Petals 4 [— 158.]
157c. Petals 5 [— 161.]
158a. Stamens 2 [— 159.]
158b. Stamens 6[CRUCIFERAE], p. 42.
158c. Stamens 8 [— 160.]
159a. Corolla perfectly regular; flowers in terminal clusters without bracts, becoming racemes; taste peppery[52a, in CRUCIFERAE], p. 46.
159b. Corolla slightly irregular; flowers in bracted clusters, or axillary; taste not peppery[40b, in SCROPHULARIACEAE], p. 104.
160a. Delicate trailing evergreen, with flowers solitary in the axils and nearly or quite hidden beneath the leaves[22b, in ERICACEAE], p. 85.
160b. Erect or nearly so; flowers in terminal clusters[12b, in ONAGRACEAE], p. 78.
161a. Leaves sword-shape, finely parallel-veined, with bristly margins[2a, in UMBELLIFERAE], p. 80.
161b. Leaves not sword-shape [— 162.]
162a. Leaves toothed or lobed [— 163.]
162b. Leaves entire [— 164.]
163a. Stems creeping[2b, in UMBELLIFERAE], p. 80.
163b. Stems erect or nearly so[SAXIFRAGACEAE], p. 49.
164a. Flowers in open panicles; leaves principally basal[SAXIFRAGACEAE], p. 49.
164b. Flowers in rounded or flattened clusters; leaves principally on the stem[SANTALACEAE], p. 24.
164c. Flowers in racemes, which become elongated at maturity [— 165.]
165a. Foliage glabrous[8b, in PRIMULACEAE], p. 87.
165b. Foliage pubescent[BORAGINACEAE], p. 93.
— 166—
166a. Juice milky or colored [— 167.]
166b. Juice watery, not colored [— 172.]
167a. Apparent flowers consisting of a few petal-like bracts, inclosing a few inconspicuous flowers without petals. In some of them a 3-lobed ovary with 3 styles may be seen[EUPHORBIACEAE], p. 66.
167b. Plants of the composite type, with several or many small flowerets closely aggregated in dense heads subtended by a calyx-like involucre of small bracts[11, in COMPOSITAE], p. 115.
167c. Flowers never aggregated in involucred clusters resembling a single flower [— 168.]
168a. Corolla very irregular; stamens protruding[LOBELIACEAE], p. 113
168b. Corolla regular [— 169.]
169a. Stamens with ordinary visible anthers; ovary 1 [— 170.]
169b. Stamens so grown together and to the stigma as to be almost unrecognizable; ovaries 2[ASCLEPIADACEAE], p. 90.
170a. Petals separate[PAPAVERACEAE], p. 41.
170b. Petals united [— 171.]
171a. Stamens attached to the tube of the corolla[CONVOLVULACEAE], p. 91.
171b. Stamens attached at the very base of the corolla[CAMPANULACEAE], p. 112.
172a. Plants of the composite type, with several or many small flowerets closely aggregated into dense heads subtended by a calyx-like involucre of small bracts [— 173.]
172b. Flowers solitary or clustered, but not in involucred heads [— 174.]
173a. True composites, without a normal calyx[COMPOSITAE], p. 113.
173b. A normal calyx with each floweret; leaves compound with 3 leaflets[LEGUMINOSAE], p. 58.
174a. Flowers irregular, i. e., the conspicuous lobes of the perianth unlike in size or shape [— 175.]
174b. Flowers regular [— 185.]
175a. Stamens 2 or 4[SCROPHULARIACEAE], p. 101.
175b. Stamens 5 [— 176.]
175c. Stamens 6 [— 181.]
175d. Stamens 8; leaves simple[POLYGALACEAE], p. 65.
175e. Stamens 10; leaves usually compound[LEGUMINOSAE], p. 58.
175f. Stamens more than 10 [— 183.]
176a. Petals separate [— 177.]
176b. Petals united [— 179.]
177a. Flowers greenish or purplish, in a panicle[SAXIFRAGACEAE], p. 49.
177b. Flowers white or purplish, in compound umbels[UMBELLIFERAE], p. 80.
177c. Flowers solitary, or in few-flowered clusters [— 178.]
178a. Flowers blue, yellow, or white, in spring[VIOLACEAE], p. 75.
178b. Flowers red-orange or yellow, in summer[BALSAMINACEAE], p. 71.
178c. Flowers small and greenish, in spring[1a, in VIOLACEAE], p. 75.
179a. Anthers united; stamens protruding from the very irregular corolla[LOBELIACEAE], p. 113.
179b. Anthers separate; corolla almost regular [— 180.]
180a. Corolla rotate; some or all filaments hairy[2, in SCROPHULARIACEAE], p. 101.
180b. Corolla funnel-form, dull yellow and purple; filaments not hairy[12a, in SOLANACEAE], p. 101.
180c. Corolla funnel-form, blue or violet; filaments not hairy[7b, in BORAGINACEAE], p. 94.
181a. Leaves compound or dissected[FUMARIACEAE], p. 41.
181b. Leaves simple [— 182.]
182a. Flowers solitary[ARISTOLOCHIACEAE], p. 25.
182b. Flowers in spikes, heads, or racemes[POLYGALACEAE], p. 65.
183a. Leaves truly compound [— 184.]
183b. Leaves palmately cleft; flowers 15 mm. wide or larger[6a, in RANUNCULACEAE], p. 36.
183c. Leaves irregularly cleft; flowers about 5 mm. wide[RESEDACEAE], p. 48.
184a. Petals prolonged backward into hollow spurs[6b, in RANUNCULACEAE], p. 36.
184b. Petals not prolonged into spurs[CAPPARIDACEAE], p. 47.
— 185—
185a. Perianth consisting of one circle of parts only (usually considered to be the calyx) [— 186.]
185b. Perianth consisting of both calyx and corolla [— 192.]
186a. Leaves with sheathing stipules encircling the stem above the base of every leaf[POLYGONACEAE], p. 25.
186b. Leaves without sheathing stipules [— 187.]
187a. Leaves entire [— 188.]
187b. Leaves toothed, lobed, or compound [— 190.]
188a. Stamens 5[SANTALACEAE], p. 24.
188b. Stamens 6 [— 189.]
188c. Stamens 10[PHYTOLACCACEAE], p. 30.
189a. Perianth-lobes 3; perianth-tube curved[ARISTOLOCHIACEAE], p. 25.
189b. Perianth-lobes 6, spreading[4a, in LILIACEAE], p. 11.
190a. Stamens 5[UMBELLIFERAE], p. 80.
190b. Stamens 6 [— 191.]
190c. Stamens more than 6[RANUNCULACEAE], p. 35.
191a. Climbing plant with heart-shape perianth[2a, in FUMARIACEAE], p. 41.
191b. Erect plant, with spreading perianth[3b, in BERBERIDACEAE], p. 40.
192a. Corolla composed of united petals [— 193.]
192b. Corolla composed of separate petals [— 208.]
193a. Stamens 2 or 4[SCROPHULARIACEAE], p. 101.
193b. Stamens 3; climbing vines[CUCURBITACEAE], p. 112.
193c. Stamens 5 [— 194.]
193d. Stamens 6[2a, in FUMARIACEAE], p. 41.
193e. Stamens 8[22b, in ERICACEAE], p. 85.
193f. Stamens 10 [— 207.]
193g. Stamens very numerous[MALVACEAE], p. 72.
194a. Ovaries 2; flowers orange-red, in umbels[7a, in ASCLEPIADACEAE], p. 91.
194b. Ovary 1, deeply 4-lobed; flowers in racemes[BORAGINACEAE], p. 93.
194c. Ovary 1, not deeply lobed [— 195.]
195a. Climbing or scrambling vines [— 196.]
195b. Not climbing or scrambling [— 198.]
196a. Flowers about 1 cm. wide [— 197.]
196b. Flowers 2-8 cm. wide[CONVOLVULACEAE], p. 91.
197a. Leaves 1 cm. wide or less[2b, in CAMPANULACEAE], p. 112.
197b. Leaves 2 cm. wide or more[4a, in SOLANACEAE], p. 100.
198a. Flowers solitary, either terminal or axillary [— 199.]
198b. Flowers in terminal clusters [— 201.]
199a. Calyx concealed by 2 bracts[CONVOLVULACEAE], p. 91.
199b. Calyx not completely concealed by bracts [— 200.]
200a. Ovary inferior, appearing as a swelling below the calyx at the base of the flower, 3-celled; stigma 3-lobed[CAMPANULACEAE], p. 112.
200b. Ovary superior, located in the center of the flower[SOLANACEAE], p. 100.
201a. Some or all filaments hairy [— 202.]
201b. Filaments not hairy [— 203.]
202a. Leaves lobed or divided[HYDROPHYLLACEAE], p. 93.
202b. Leaves not lobed[2, in SCROPHULARIACEAE], p. 101.
203a. Anthers close together, longer than the filaments[2, in SOLANACEAE], p. 100.
203b. Anthers separate from each other [— 204.]
204a. Leaves compound or very deeply lobed [— 205.]
204b. Leaves simple or with shallow lobes only [— 206.]
205a. Leaf-segments linear or oblong, irregular[HYDROPHYLLACEAE], p. 93.
205b. Leaves truly compound with separate leaflets[1a, in POLEMONIACEAE], p. 92.
206a. Flowers greenish-yellow[SOLANACEAE], p. 100.
206b. Flowers blue, violet, white, or intermediate tints[CAMPANULACEAE], p. 112.
207a. Leaves simple[ERICACEAE], p. 84.
207b. Leaves compound[OXALIDACEAE], p. 64.
— 208—
208a. Petals 4 [— 209.]
208b. Petals 5 [— 212.]
208c. Petals 6 or more [— 227.]
209a. Stamens 4 or 8 [— 210.]
209b. Stamens 6, 4 long and 2 short[CRUCIFERAE], p. 42.
209c. Stamens 9 or more[CAPPARIDACEAE], p. 47.
210a. Leaves compound[ROSACEAE], p. 51.
210b. Leaves simple [— 211.]
211a. Ovary 1, inferior, appearing as a swelling below the calyx[ONAGRACEAE], p. 78.
211b. Ovaries 4 or 5, in the center of the flower[CRASSULACEAE], p. 48.
212a. Stamens with good anthers 5 [— 213.]
212b. Stamens 6 to 10 [— 217.]
212c. Stamens more than 10 [— 222.]
213a. Flowers solitary, terminating the stem[12b, in SAXIFRAGACEAE], p. 50.
213b. Flowers axillary, solitary or in small clusters [— 214.]
213c. Flowers several, in loose irregular terminal clusters; leaves simple[LINACEAE], p. 63.
213d. Flowers in slender spike-like racemes; leaves compound[50b, in ROSACEAE], p. 55.
213e. Flowers in panicles[20a, in SAXIFRAGACEAE], p. 50.
213f. Flowers in umbels [— 216.]
214a. Leaves compound[25b, in LEGUMINOSAE], p. 60.
214b. Leaves simple [— 215.]
215a. Flowers blue or yellow, erect or spreading[LINACEAE], p. 63.
215b. Flowers greenish, nodding[1a, in VIOLACEAE], p. 75.
216a. Flowers pink or purple[GERANIACEAE], p. 64.
216b. Flowers yellow or white[UMBELLIFERAE], p. 80.
217a. Leaves compound with 3 leaflets [— 218.]
217b. Leaves pinnately compound [— 219.]
217c. Leaves deeply palmately lobed[GERANIACEAE], p. 64.
217d. Leaves simple and not deeply lobed [— 220.]
218a. Leaflets reverse heart-shape; flowers yellow[OXALIDACEAE], p. 64.
218b. Leaflets taper-pointed; flowers white or pink[73, in ROSACEAE], p. 57.
219a. Leaflets entire[24, in LEGUMINOSAE], p. 60.
219b. Leaflets toothed[50b, in ROSACEAE], p. 55.
220a. Prostrate plants, with thick, fleshy, entire leaves[3, in PORTULACACEAE], p. 34.
220b. Bushy branched plants, with small gray leaves concealing the stem[2a, in CISTACEAE], p. 74.
220c. Erect or spreading plants [— 221.]
221a. Ovary 1, style 1[4a, in ERICACEAE], p. 84.
221b. Ovary with 2 distinct styles[SAXIFRAGACEAE], p. 49.
221c. Ovaries 5; styles 5[CRASSULACEAE], p. 48.
222a. Stamens united by their filaments into a tube[MALVACEAE], p. 72.
222b. Stamens separate from each other [— 223.]
223a. Leaves with stipules; ovaries more than 1[ROSACEAE], p. 51.
223b. Leaves without stipules [— 224.]
224a. Leaves toothed, deeply lobed, or compound[RANUNCULACEAE], p. 35.
224b. Leaves entire [— 225.]
225a. Ovaries numerous[RANUNCULACEAE], p. 35.
225b. Ovary 1 [— 226.]
226a. Sepals 2[PORTULACACEAE], p. 34.
226b. Sepals 3 or 5[CISTACEAE], p. 74.
— 227—
227a. Leaves entire[LYTHRACEAE], p. 77.
227b. Leaves lobed, divided, dissected, or compound [— 228.]
228a. Flowers in slender racemes[RESEDACEAE], p. 48.
228b. Flowers solitary or clustered, but not in slender racemes [— 229.]
229a. Stamens 6[3b, in BERBERIDACEAE], p. 40.
229b. Stamens numerous[RANUNCULACEAE], p. 35.