RUBIACEAE, the Madder family
Herbs or shrubs, with opposite or whorled leaves and regular flowers; sepals 4, or minute or almost wanting; petals 4, united; stamens 4; ovary inferior.
| 1a. Shrub (1-3 m. tall; flowers white, in spherical heads, summer) | Button Bush, Cephalanthus occidentalis. |
| 1b. Herbaceous [— 2.] | |
| 2a. Leaves opposite [— 3.] | |
| 2b. Leaves whorled; flowers white, green, or purple (Bedstraw) [— 6.] | |
| 2c. Leaves whorled; flowers yellow | Bedstraw, Galium verum. |
| 3a. Leaves about as long as wide (trailing; flowers paired, white, in spring) | Partridge Berry, Mitchella repens. |
| 3b. Leaves at least twice as long as wide [— 4.] | |
| 4a. Corolla salver-form, about 1 cm. wide; peduncles 1-flowered (about 1 dm. high; flowers blue or white, in spring) | Bluets, Houstonia coerulea. |
| 4b. Corolla funnel-form, about 5 mm. wide; flowers in clusters (1-2 dm. high; flowers white or pale-purple, summer) (Houstonia) [— 5.] | |
| 5a. Basal leaves strongly ciliate | Houstonia, Houstonia ciliolata. |
| 5b. Basal leaves smooth | Houstonia, Houstonia longifolia. |
| 6a. Leaves in whorls of 4-7. | |
| 6b. Leaves in whorls of 6-8 [— 16.] | |
| 7a. Ovary and fruit hispid with hooked bristles (3-7 dm. high; summer) [— 8.] | |
| 7b. Ovary and fruit not bristly (early summer) [— 11.] | |
| 8a. Leaves with 1 principal vein (flowers dull purple) | Bedstraw, Galium pilosum. |
| 8b. Leaves with 3 principal veins [— 9.] | |
| 9a. Flowers bright-white | Bedstraw, Galium boreale. |
| 9b. Flowers greenish, yellowish, or purplish [— 10.] | |
| 10a. Leaves acuminate | Bedstraw, Galium lanceolatum. |
| 10b. Leaves acute or obtuse | Bedstraw, Galium circaezans. |
| 11a. Corolla-lobes 3 (2-6 dm. high; flowers white or greenish) [— 12.] | |
| 11b. Corolla-lobes 4 [— 13.] | |
| 12a. Flowers in clusters of 2 or 3 | Bedstraw, Galium claytoni. |
| 12b. Flowers solitary in the axils, on long hair-like pedicels | Bedstraw, Galium trifidum. |
| 13a. Corolla brownish or purple (3-6 dm. high) | Bedstraw, Galium latifolium. |
| 13b. Corolla white (1-4 dm. high) [— 14.] | |
| 14a. Flowers rather numerous in small cymes | Bedstraw, Galium palustre. |
| 14b. Flowers in clusters of 2 or 3, or solitary [— 15.] | |
| 15a. Principal leaves spreading or ascending | Bedstraw, Galium tinctorium. |
| 15b. Principal leaves recurved or reflexed | Bedstraw, Galium labradoricum. |
| 16a. Ovary and fruit bristly or hispid [— 17.] | |
| 16b. Ovary and fruit not bristly (summer) [— 18.] | |
| 17a. Leaves narrowly lanceolate to linear, mostly 6-8 in a whorl (stem 5-15 dm. long; flowers white; spring and summer) | Bedstraw, Galium aparine. |
| 17b. Leaves narrowly oval or elliptical, mostly in whorls of 6; flowers in clusters of 3 (1-5 dm. high; flowers greenish, summer) | Bedstraw, Galium triflorum. |
| 18a. Leaves cuspidate or mucronate at the apex (flowers white) [— 19.] | |
| 18b. Leaves obtuse at the apex (flowers white or greenish; 2-6 dm. high) [— 20.] | |
| 19a. Flowers very numerous in terminal panicles (stem 3-8 dm. long) | Bedstraw, Galium mollugo. |
| 19b. Flowers in axillary clusters (1-3 dm. high) | Bedstraw, Galium tricorne. |
| 19c. Flowers few, in small loose terminal cymes [— 20.] | |
| 20a. Stem smooth or nearly so (2-4 dm. high) | Bedstraw, Galium concinnum. |
| 20b. Stem hispid with reflexed bristles (5-15 dm. long) | Bedstraw, Galium asprellum. |
CAPRIFOLIACEAE, the Honeysuckle Family
Shrubs or herbs, with opposite leaves; corolla regular or irregular, petals 4 or 5, united; stamens 4 or 5; ovary inferior, 1-5-celled.
| 1a. Leaves compound (shrubs 1-4 m. high; flowers white, in large clusters in early summer) (Elder) [— 2.] | |
| 1b. Leaves simple [— 3.] | |
| 2a. Pith of the twigs white; inflorescence flattened or convex | Elder, Sambucus canadensis. |
| 2b. Pith of the twigs brown; inflorescence pyramidal | Elder, Sambucus racemosa. |
| 3a. Plant trailing; flowers nodding, in pairs (1 dm. high; flowers pink, summer) | Twin Flower, Linnaea borealis var. americana. |
| 3b. Erect herbs (6-12 dm. high; flowers dull-red, axillary, early summer) (Feverwort) [— 4.] | |
| 3c. Shrubs, small trees, or woody vines [— 5.] | |
| 4a. Leaf-bases broadly connate and 2-5 cm. wide | Feverwort, Triosteum perfoliatum. |
| 4b. Leaf-bases narrowly connate, not over 1 cm. wide | Feverwort, Triosteum aurantiacum. |
| 5a. Climbing vines (spring and early summer) (Honeysuckle) [— 6.] | |
| 5b. Erect or spreading shrubs or small trees [— 11.] | |
| 6a. Flowers in 2-flowered axillary clusters (flowers white or pink) | Honeysuckle, Lonicera japonica. |
| 6b. Flowers in terminal clusters [— 7.] | |
| 7a. Leaves distinctly pubescent beneath (flowers yellow) [— 8.] | |
| 7b. Leaves glabrous beneath, or very minutely puberulent [— 9.] | |
| 8a. Leaves pubescent above | Honeysuckle, Lonicera hirsuta. |
| 8b. Leaves glabrous above | Honeysuckle, Lonicera glaucescens. |
| 9a. Corolla purple on the outside, glabrous within | Honeysuckle, Lonicera caprifolium. |
| 9b. Corolla yellow on the outside (or slightly tinged with purple), pubescent within [— 10.] | |
| 10a. Corolla-tube 6-8 mm. long | Honeysuckle, Lonicera dioica. |
| 10b. Corolla-tube 11-14 mm. long | Honeysuckle, Lonicera sullivantii. |
| 11a. Corolla tubular at base; style long and slender [— 12.] | |
| 11b. Corolla rotate or somewhat bell-shape, style very short (flowers white, late spring or early summer) [— 22.] | |
| 12a. Flowers yellow or yellowish (spring and early summer) [— 13.] | |
| 12b. Flowers white, pink, or red [— 18.] | |
| 13a. Leaves serrate (5-10 dm. tall) | Bush Honeysuckle, Diervilla lonicera. |
| 13b. Leaves entire; flowers in pairs (Honeysuckle) [— 14.] | |
| 14a. Each pair of flowers subtended by 2 broad leaf-like bracts (1-3 m. high) | Honeysuckle, Lonicera involucrata. |
| 14b. Bracts at the base of each pair of flowers linear or narrowly lanceolate [— 15.] | |
| 15a. Native species of woods and bogs [— 16.] | |
| 15b. Introduced species, growing mostly near dwellings; leaves very pubescent beneath | Honeysuckle, Lonicera xylosteum. |
| 16a. Peduncles 15 mm. long or more (1-4 m. high) [— 17.] | |
| 16b. Peduncles about 5 mm. long (1 m. high, or less) | Honeysuckle, Lonicera coerulea var. villosa. |
| 17a. Leaves ciliate | Honeysuckle, Lonicera canadensis. |
| 17b. Leaves not ciliate | Honeysuckle, Lonicera oblongifolia. |
| 18a. Corolla irregular, over 1 cm. long (1-4 m. high; spring) | Honeysuckle, Lonicera tatarica. |
| 18b. Corolla regular, less than 1 cm. long (5-15 dm. high; flowers white or pink, in axillary clusters, early summer) [— 19.] | |
| 19a. Flowers in axillary spikes | Wolfberry, Symphoricarpos occidentalis. |
| 19b. Flowers almost sessile in the axils [— 20.] | |
| 20a. Flowers numerous in each axil | Indian Currant, Symphoricarpos orbiculatus. |
| 20b. Flowers 1 or 2 in each axil (Snowberry) [— 21.] | |
| 21a. Leaves green beneath | Snowberry, Symphoricarpos racemosus. |
| 21b. Leaves whitened beneath | Snowberry, Symphoricarpos racemosus var. pauciflorus. |
| 22a. Leaves palmately lobed [— 23.] | |
| 22b. Leaves not lobed [— 25.] | |
| 23a. Outermost flowers of the cluster enlarged and imperfect (1-4 m. high) | Cranberry Tree, Viburnum opulus var. americanum. |
| 23b. All flowers of the cluster alike [— 24.] | |
| 24a. Flower-clusters 4-10 cm. broad (1-2 m. high) | Arrow Wood, Viburnum acerifolium. |
| 24b. Flower-clusters 2-3 cm. broad | Squashberry, Viburnum pauciflorum. |
| 25a. Outer flowers of the cluster enlarged and imperfect (1-3 m. high) | Hobble-bush, Viburnum alnifolium. |
| 25b. All flowers of the cluster alike [— 26.] | |
| 26a. Leaves finely serrate; the veins not prominent [— 27.] | |
| 26b. Leaves coarsely serrate, all or most of the teeth terminating in a prominent vein [— 29.] | |
| 27a. Peduncle of the flower-cluster, below its branches, at least 2 cm. long (1-3 m. high) | Withe-rod, Viburnum cassinoides. |
| 27b. Peduncle of the cluster 1 cm. long, or even shorter (3-8 m. high) [— 28.] | |
| 28a. Leaves distinctly acuminate | Sheep-berry, Viburnum lentago. |
| 28b. Leaves obtuse or barely acute | Black Haw, Viburnum prunifolium. |
| 29a. Leaves densely pubescent beneath (6-15 dm. high) | Arrow-wood, Viburnum pubescens. |
| 29b. Leaves glabrous beneath, or with tufts of hairs in the forks of the veins (1-4 m. high) | Arrow-wood, Viburnum dentatum. |
VALERIANACEAE, the Valerian Family
Herbs with opposite leaves and small nearly or quite regular flowers; petals 5, united; stamens 3; sepals minute or wanting; ovary inferior.
| 1a. Stem-leaves pinnately cleft (3-10 dm. high; flowers white or pinkish, summer) [— 2.] | |
| 1b. Stem-leaves entire or dentate (2-6 dm. high; flowers white, summer) (Corn Salad) [— 3.] | |
| 2a. Leaf-segments parallel-veined Valerian, Valeriana edulis. | |
| 2b. Leaf-segments net-veined | Swamp Valerian, Valeriana uliginosa. |
| 3a. Upper stem-leaves entire | Corn Salad, Valerianella chenopodifolia. |
| 3b. Upper stem-leaves dentate | Corn Salad, Valerianella radiata. |