| 1a. Flowers without petal-like or brightly colored parts; staminate and pistillate flowers in separate heads (or rarely in the same heads); coarse weeds with inconspicuous flowers (summer and autumn) [— 2.] | |
| 1b. Flowers with some petal-like parts, usually brightly colored or white [— 10.] | |
| 2a. Leaves toothed or lobed — 3. | |
| 2b. Leaves deeply pinnatifid or dissected (4-15 dm. high; flowers in erect spikes) (Ragweed) [— 7.] | |
| 3a. Fruit or pistillate flowers thickly covered with sharp hooked spines (3-10 dm. high) (Cocklebur) [— 4.] | |
| 3b. Fruit not spiny [— 8.] | |
| 4a. With spines on the stem at the base of the leaves | Cocklebur, Xanthium spinosum. |
| 4b. Without any spines on the stem [— 5.] | |
| 5a. Body of the bur smooth or slightly hairy | Cocklebur, Xanthium canadense. |
| 5b. Body of the bur and the spines densely pubescent [— 6.] | |
| 6a. Body of the bur more than twice as long as thick; a common weed | Cocklebur, Xanthium commune. |
| 6b. Body of the bur less than twice as long as thick | Cocklebur, Xanthium echinatum. |
| 7a. Leaves twice-pinnatifid | Ragweed, Ambrosia artemisiifolia. |
| 7b. Leaves once-pinnatifid | Ragweed, Ambrosia psilostachya. |
| 8a. Leaves deeply 3-lobed (1-5 m. high) | Giant Ragweed, Ambrosia trifida. |
| 8b. Leaves serrate or obscurely lobed [— 9.] | |
| 9a. Stem simple or sparingly branched; pistillate heads in the axils of the upper leaves (1-3 m. high) | Giant Ragweed, Ambrosia trifida var. integrifolia. |
| 9b. Stem much branched; heads all alike, in panicles | Marsh Elder, Iva xanthifolia. |
| 10a. Flowers all strap-shape; juicy milky. (The central flowers must be examined carefully, since they are frequently much smaller than the marginal ones) [— 11.] | |
| 10b. Flowers all tubular, with regular. 4-5-lobed corollas [— 45.] | |
| 10c. Flowers both tubular and strap-shape; heads radiate (in a few species the rays are small and may be overlooked by mistake) [— 108.] | |
| 11a. Flowers blue (summer and autumn) [— 12.] | |
| 11b. Flowers orange, yellow, white, or purplish [— 15.] | |
| 12a. Heads 2.5 cm. wide, or larger [— 13.] | |
| 12b. Heads 1.5 cm. wide, or smaller [— 14.] | |
| 13a. Leaves linear; bracts longer than the flowers, heads 5-10 cm. wide (6-15 dm. high) | Salsify, Tragopogon porrifolius. |
| 13b. Leaves broader, mostly serrate; bracts shorter than the flowers; heads 2.5-4 cm. wide | Chicory, Cichorium intybus. |
| 14a. Heads in a narrow crowded cluster (5-15 dm. high) — 30b. | |
| 14b. Heads in a spreading open panicle (Wild Lettuce) [— 22.] | |
| 15a. Heads solitary at the summit of leafless stalks [— 16.] | |
| 15b. Heads several, on leafy, naked, or scaly stalks [— 19.] | |
| 16a. Basal leaves strictly entire; heads about 2.5 cm. wide (summer and autumn) — 35a. | |
| 16b. Basal leaves toothed, lobed, or pinnatifid (spring and summer) [— 17.] | |
| 17a. Heads 8-14 mm. wide (1-4 dm. high) | Dwarf Dandelion, Krigia virginica. |
| 17b. Heads 25-50 mm. wide (1-6 dm. high) (Dandelion) [— 18.] | |
| 18a. Outer involucral bracts reflexed | Dandelion, Taraxacum officinale. |
| 18b. Outer involucral bracts erect or spreading | Dandelion, Taraxacum erythrospermum. |
| 19a. Pappus none; heads about 1 cm. wide (4-10 dm. high; summer) | Nipplewort, Lapsana communis. |
| 19b. Pappus of an inner row of bristles and an outer row of short scales; heads about 3 cm. wide (3-8 dm. high; early summer) | Cynthia, Krigia amplexicaulis. |
| 19c. Pappus of feathery bristles (summer) [— 20.] | |
| 19d. Pappus of simple bristles [— 25.] | |
| 20a. Flower-stalk scaly, without foliage leaves (2-6 dm. high) | Fall Dandelion, Leontodon autumnalis. |
| 20b. Stem leafy (3-10 dm. high) [— 21.] | |
| 21a. Leaves entire, linear-lanceolate | Meadow Salsify, Tragopogon pratensis. |
| 21b. Leaves serrate, oblong-lanceolate | Picris, Picris hieracioides. |
| 22a. Pappus tawny in color (1-3 m. high) [— 23.] | |
| 22b. Pappus white [— 24.] | |
| 23a. Leaves pinnatifid | Wild Lettuce, Lactuca spicata. |
| 23b. Leaves undivided, dentate | Wild Lettuce, Lactuca spicata var. integrifolia. |
| 24a. Upper leaves entire; heads about 1.5 cm. wide (5-10 dm. high) | Wild Lettuce, Lactuca pulchella. |
| 24b. Upper leaves dentate or lobed; heads about 1 cm. wide (1-3 m. high) | Wild Lettuce, Lactuca floridana. |
| 25a. Achene tipped with a slender beak, bearing the pappus at its summit (summer) (Wild Lettuce) [— 26.] | |
| 25b. Achene without a beak [— 29.] | |
| 26a. Leaves hirsute or hispid on the mid-veins beneath [— 27.] | |
| 26b. Leaves glabrous [— 28.] | |
| 27a. Leaves pubescent on both sides (1-2 m. high) | Wild Lettuce, Lactuca hirsuta. |
| 27b. Leaves glabrous, except on the mid-vein (5-15 dm. high) | Wild Lettuce, Lactuca scariola var. integrata. |
| 28a. Leaves entire or sparsely toothed (1-2 m. high) | Wild Lettuce, Lactuca sagittifolia. |
| 28b. Leaves chiefly sinuate-pinnatifid (1-3 m. high) | Wild Lettuce, Lactuca canadensis. |
| 29a. Flowers white, cream-color, or purplish (summer and autumn) (Rattlesnake Root) [— 30.] | |
| 29b. Flowers bright-yellow or orange [— 33.] | |
| 30a. Heads nodding (6-20 dm. high) [— 31.] | |
| 30b. Heads pointing in various directions, in spike-like panicles; involucres pubescent (5-15 dm. high) | Rattlesnake Root, Prenanthes racemosus. |
| 31a. Heads with 5-7 flowers in each | Rattlesnake Root, Prenanthes altissima. |
| 31b. Heads with 8-12 flowers [— 32.] | |
| 31c. Heads with 20 or more flowers | Rattlesnake Root, Prenanthes crepidinea. |
| 32a. Pappus dark reddish-brown | Rattlesnake Root, Prenanthes alba. |
| 32b. Pappus pale-brown or nearly white | Rattlesnake Root, Prenanthes trifoliata. |
| 33a. Pappus tawny or brown in color (summer and autumn) (Hawkweed) [— 34.] | |
| 33b. Pappus white [— 42.] | |
| 34a. Heads 2.5 cm. in diameter, or larger [— 35.] | |
| 34b. Heads 1-2 cm. in diameter (4-10 dm. high) [— 37.] | |
| 35a. Leaves all basal (1-4 dm. high) | Hawkweed, Hieracium pilosella. |
| 35b. Stem-leaves present (4-15 dm. high) [— 36.] | |
| 36a. Leaves rounded at the sessile base | Hawkweed, Hieracium canadense. |
| 36b. Leaves narrowed toward the base | Hawkweed, Hieracium umbellatum. |
| 37a. A rosette of basal leaves conspicuous at flowering time [— 38.] | |
| 37b. No rosette of basal leaves at time of flowering [— 41.] | |
| 38a. Leaves glabrous on the upper side [— 39.] | |
| 38b. Leaves hairy on the upper side [— 40.] | |
| 39a. Stem glabrous, leafless or with one or two leaves | Hawkweed, Hieracium venosum. |
| 39b. Stem with several leaves, hairy below | Hawkweed, Hieracium marianum. |
| 40a. Leaves with short scattered hairs above | Hawkweed, Hieracium gronovii. |
| 40b. Leaves and stem densely covered with very long hairs | Hawkweed, Hieracium longipilum. |
| 41a. Leaves glabrous | Hawkweed, Hieracium paniculatum. |
| 41b. Leaves very hairy | Hawkweed, Hieracium scabrum. |
| 42a. Bracts of the involucre smooth (5-20 dm. tall; summer and autumn) (Sow Thistle) [— 43.] | |
| 42b. Bracts of the involucre hairy [— 44.] | |
| 43a. The clasping leaf-bases acute | Sow Thistle, Sonchus oleraceus. |
| 43b. The clasping leaf-bases rounded | Sow Thistle, Sonchus asper. |
| 44a. Heads 2.5-5 cm. broad; involucre 2 cm. long (4-10 dm. high) | Sow Thistle, Sonchus arvensis. |
| 44b. Heads 1-2 cm. broad; involucre 6-10 mm. long (3-6 dm. high; summer) | Hawksbeard, Crepis tectorum. |
| 45a. Leaves or involucre or both spiny (thistles, burdock, etc.) [— 46.] | |
| 45b. Neither leaves nor involucre spiny [— 60.] | |
| 46a. Leaves 1-4 dm. broad, not spiny (flowers purple or white; summer) (Burdock) [— 47.] | |
| 46b. Leaves narrower, not spiny [— 48.] | |
| 47a. Diameter of involucre at flowering time 3-5 cm. (1-3 m. high) | Burdock, Arctium lappa. |
| 47b. Diameter of involucre at flowering time 1.5-3 cm. (5-15 dm. high) | Burdock, Arctium minus. |
| 48a. Each head 1-flowered; heads aggregated in a globular head-like cluster (1-2 m. high; flowers blue or white, summer) | Globe Thistle, Echinops sphaerocephalus. |
| 48b. Each head many-flowered [— 49.] | |
| 49a. Principal involucral bracts with stout spreading spines 2-4 cm. long (5-15 dm. high; flowers purple, summer) | Milk Thistle, Silybum marianum. |
| 49b. Principal involucral bracts with slender spines or none [— 50.] | |
| 50a. Pappus feathery; receptacle bristly (summer and autumn) (Thistle) [— 51.] | |
| 50b. Pappus not feathery (flowers purple, summer) [— 59.] | |
| 51a. Heads subtended by a circle of large leafy bracts (5-15 dm. high; flowers pale-yellow) | Thistle, Cisium spinoissimum. |
| 51b. Heads not subtended by several leafy bracts [— 52.] | |
| 52a. Leaves conspicuously white-woolly on both sides (4-10 dm. high) [— 53.] | |
| 52b. Leaves conspicuously white-woolly or brown-woolly below, not above (flowers purple or pink) [— 54.] | |
| 52c. Leaves green on both sides (flowers pink or purple, rarely white) [— 56.] | |
| 53a. Leaves deeply pinnately parted with linear divisions; flowers almost white | Thistle, Cirsium pitcheri. |
| 53b. Leaves irregularly pinnatifid; flowers purple-pink | Thistle, Cirsium undulatum. |
| 54a. Stem-leaves entire or shallowly lobed (1-3 m. high) | Thistle, Cirsium altissimum. |
| 54b. Stem-leaves obviously pinnatifid (1-2 m. high) [— 55.] | |
| 55a. Leaves decurrent on the stem | Thistle, Cirsium lanceolatum. |
| 55b. Leaves not decurrent | Thistle, Cirsium discolor. |
| 56a. Outer and middle involucral bracts appressed, pointless or with weak short prickles [— 57.] | |
| 56b. Outer and middle bracts erect, not appressed, acuminate into a long slender more or less prickly tip (4-10 dm. high) [— 58.] | |
| 57a. Heads numerous 2-2.5 cm. broad, in close clusters (5-12 dm. high) | Canada Thistle, Cirsium arvense. |
| 57b. Heads few or solitary, 3-5 cm. broad (1-2 m. high) | Thistle, Cirsium muticum. |
| 58a. Principal bracts with a conspicuous viscid stripe down the middle; heads 6-19 cm. broad, solitary or few | Thistle, Cirsium hillii. |
| 58b. Principal bracts not viscid | Thistle, Cirsium pumilum. |
| 59a. Receptacle not bristly; heads 3-5 cm. wide (1-3 m. high; flowers pale-purple, summer) | Cotton Thistle, Onopordum acanthium. |
| 59b. Receptacle bristly; heads 2-2.5 cm. wide (5-12 dm. high; flowers purple to white, late summer) | Thistle, Carduus crispus. |
| 60a. Leaves basal; stem-leaves none or reduced to scales (2-8 dm. high; flowers whitish, in spring) [— 61.] | |
| 60b. Stem-leaves present; basal leaves present or absent [— 62.] | |
| 61a. Leaves toothed or lobed; flower-stalk not scaly | Adenocaulon, Adenocaulon bicolor. |
| 61b. Leaves deeply cleft; flower-stalk scaly — 197a. | |
| 62a. Leaves compound or dissected (flowers in summer and autumn) [— 63.] | |
| 62b. Leaves merely lobed, never truly compound or dissected [— 72.] | |
| 62c. Leaves entire or serrate [— 78.] | |
| 63a. Some of the involucral bracts leaf-like, longer than the heads (3-20 dm. high; flowers yellow or greenish, summer and autumn) (Beggar Ticks) [— 126.] | |
| 63b. Bracts short and not leaf-like [— 64.] | |
| 64a. Heads 7-20 mm. wide, in a flat-topped or convex cluster (3-10 dm. high; flowers yellow, summer) (Tansy) [— 65.] | |
| 64b. Heads smaller, in spikes, racemes, or panicles (flowers yellow or greenish, late summer and autumn) (Wormwood) [— 66.] | |
| 65a. Heads 7-10 mm. wide, numerous in a dense cluster | Tansy, Tanacetum vulgare. |
| 65b. Heads 10-20 mm. wide, few, 2-10 in a loose open cluster | Tansy, Tanacetum huronense. |
| 66a. Heads 2-3 mm. broad (4-15 dm. high) [— 67.] | |
| 66b. Heads 4-6 mm. broad (3-10 dm. high) [— 69.] | |
| 67a. Leaf-lobes narrowly linear, strictly entire | Wormwood, Artemisia caudata. |
| 67b. Leaf-lobes serrate [— 68.] | |
| 68a. Heads in a loose spreading panicle | Wormwood, Artemisia annua. |
| 68b. Heads in axillary clusters, producing a leafy spike-like panicle | Wormwood, Artemisia biennis. |
| 69a. Leaf-lobes narrowly linear [— 70.] | |
| 69b. Leaf-lobes oblong to obovate, not linear [— 71.] | |
| 70a. Shrubby; involucre pubescent | Southernwood, Artemisia abrotanum. |
| 70b. Herbaceous; involucre glabrous or rarely pubescent | Wormwood, Artemisia canadensis. |
| 71a. Leaves finely gray-pubescent on both sides | Wormwood, Artemisia absinthium. |
| 71b. Leaves smooth or nearly so above, densely white-woolly beneath | Mugwort, Artemisia vulgaris. |
| 72a. Heads 2-4 cm. broad, purple, blue, or rarely white (3-6 dm. high; summer) [— 92.] | |
| 72b. Heads 1 cm. wide or less [— 73.] | |
| 73a. Leaves densely white-woolly beneath (flowers yellowish, late summer) [— 74.] | |
| 73b. Leaves smooth or hairy, never white-woolly [— 75.] | |
| 74a. Heads 6-8 mm. wide (4-8 dm. high) | Wormwood, Artemisia stelleriana. |
| 74b. Heads 3-4 mm. wide (5-10 dm. high) | Wormwood, Artemisia ludoviciana. |
| 75a. Principal bracts of the involucre 5, with frequently a few much smaller ones [— 76.] | |
| 75b. Principal bracts of the involucre numerous [— 77.] | |
| 76a. Heads few in small terminal clusters; foliage somewhat viscid-pubescent (6-15 dm. high; flowers yellow, summer) — 114a. | |
| 76b. Heads very numerous in flat-topped clusters; foliage never viscid-pubescent (1-2 m. high; flowers white, late summer) — 105c. | |
| 77a. Leaves broadly halberd-shape, 3-lobed (1-2 m. high; flowers white, late summer) — 105b. | |
| 77b. Leaves lobed only at the base (5-10 dm. high; flowers yellow, summer) — 93a. | |
| 77c. Leaves pinnatifid (2-8 dm. high; flowers yellow) [— 172.] | |
| 78a. Bracts of the involucre dry and chaffy, at least at the tip; plants always pubescent and usually white-woolly [— 79.] | |
| 78b. Bracts of the involucre green or colored, but never dry and chaffy [— 90.] | |
| 79a. Pappus none; heads 3-4 mm. wide, in ample panicled spikes (flowers yellowish, late summer) — 74b. | |
| 79b. Pappus a minute ring or crown; leaves crenate (5-10 dm. high; flowers yellow, summer) — 93a. | |
| 79c. Pappus of hairs; heads in flat-topped clusters or slender spikes [— 80.] | |
| 80a. Heads sessile or subsessile in small flat-topped clusters; flowering in spring or early summer; principal leaves basal (1-4 dm. high; flowers white or purplish) (Everlasting) [— 81.] | |
| 80b. Heads in terminal spikes (2-6 dm. high; flowers purplish, summer) | Cudweed, Gnaphalium purpureum. |
| 80c. Heads in small or large flat-topped clusters, flowering in summer or autumn; principal leaves on the stem [— 88.] | |
| 81a. Stolons from the basal rosette of leaves leafy throughout and ascending at the tip [— 82.] | |
| 81b. Stolons prostrate throughout, leafy only at the tip [— 87.] | |
| 82a. Basal leaves 2-5 cm. long, 1-nerved [— 83.] | |
| 82b. Basal leaves 5-12 cm. long, 3-nerved [— 84.] | |
| 83a. Basal leaves spatulate or oblanceolate, smooth above | Everlasting, Antennaria canadensis. |
| 83b. Basal leaves obovate, pubescent above | Everlasting, Antennaria neodioica. |
| 84a. Basal leaves smooth above | Everlasting, Antennaria parlinii. |
| 84b. Basal leaves dull green and pubescent above [— 85.] | |
| 85a. Heads 6-8 mm. high | Everlasting, Antennaria plantaginifolia. |
| 85b. Heads 8-11 mm. high [— 86.] | |
| 86a. Leaf-blade ovate or obovate | Everlasting, Antennaria fallax. |
| 86b. Leaf-blade spatulate, with rounded tip | Everlasting, Antennaria occidentalis. |
| 87a. Styles crimson | Everlasting, Antennaria neglecta. |
| 87b. Styles pale yellow | Everlasting, Antennaria petaloidea. |
| 88a. Erect; involucral bracts pearly white (4-9 dm. high) | Pearly Everlasting, Anaphalis margaritacea. |
| 88b. Erect; involucral bracts dull white or pale brown, somewhat pubescent (4-8 dm. high) (Cudweed) [— 89.] | |
| 88c. Diffusely branched; heads in dense clusters; bracts brown (1-2 dm. high) | Cudweed, Gnaphalium uliginosum. |
| 89a. Leaves decurrent on the stem | Cudweed, Gnaphalium decurrens. |
| 89b. Leaves not decurrent on the stem | Cudweed, Gnaphalium polycephalum. |
| 90a. Twining vine (flowers white, summer) | Hemp Weed, Mikania scandens. |
| 90b. Not twining or climbing [— 91.] | |
| 91a. Involucral bracts deeply fringed at the tip (flowers purple, blue, or rarely white, summer; 3-6 dm. high) [— 92.] | |
| 91b. Involucral bracts entire or nearly so [— 93.] | |
| 92a. Upper leaves linear or narrowly lanceolate | Corn Flower, Centaurea cyanus. |
| 92b. Upper leaves oblong or oblong-lanceolate | Knapweed, Centaurea nigra. |
| 93a. Pappus none or a short ring or crown (5-10 dm. high; flowers yellow, summer) | Costmary, Chrysanthemum balsamita var. tanacetoides. |
| 93b. Pappus of 2-4 stiff awns (2-15 dm. high; flowers yellow, late summer) (Bur Marigold) [— 130.] | |
| 93c. Pappus of hairs or bristles [— 94.] | |
| 94a. Leaves linear or narrowly lanceolate, entire; heads never in a large flat-topped cluster [— 95.] | |
| 94b. Leaves not linear [— 99.] | |
| 95a. Heads showy, purple, in a long spike or raceme (late summer) (Blazing Star) [— 96.] | |
| 95b. Heads not showy, in a loose panicle or raceme — 240b. | |
| 96a. Involucral bracts rounded at the tip, appressed (5-15 dm. high) [— 97.] | |
| 96b. Involucral bracts pointed (3-6 dm. high) [— 98.] | |
| 97a. Heads 8-12-flowered | Blazing Star, Liatris spicata. |
| 97b. Heads with 25 flowers or more | Blazing Star, Liatris scariosa. |
| 98a. Involucral bracts long-acuminate, spreading | Blazing Star, Liatris squarrosa. |
| 98b. Involucral bracts mucronate, appressed | Blazing Star, Liatris cylindracea. |
| 99a. Flowers yellow (2-8 dm. high) — 172b. | |
| 99b. Flowers bright-red or purple, in flat-topped clusters (8-20 dm. high; late summer) (Ironweed) [— 100.] | |
| 99c. Flowers blue (3-8 dm. high; late summer) | Mist Flower, Eupatorium coelestinum. |
| 99d. Flowers flesh-color, pink, cream-color, or white (flowers in summer) [— 103.] | |
| 100a. Leaves glabrous beneath or minutely pubescent; heads 15-30-flowered [— 101.] | |
| 100b. Leaves tomentose beneath; heads 30-50-flowered [— 102.] | |
| 101a. Inflorescence densely crowded; usually 1 m. or less high | Ironweed, Vernonia fasciculate. |
| 101b. Inflorescence loose and open, 15-30 cm. wide; 1-2 m. high | Ironweed, Vernonia altissima. |
| 102a. Pappus tawny in color | Ironweed, Vernonia missurica. |
| 102b. Pappus purple | Ironweed, Vernonia illinoensis. |
| 103a. Leaves alternate [— 104.] | |
| 103b. Leaves opposite [— 106.] | |
| 103c. Leaves whorled (1-3 m. high; flowers pink or purple, late summer) (Joe-Pye Weed) [— 107.] | |
| 104a. Heads 5-flowered (5-20 dm. high; flowers white or pinkish, late summer) (Indian Plantain) [— 105.] | |
| 104b. Heads 10 25-flowered (5-10 dm. high; flowers white, late summer) | False Boneset, Kuhnia eupatorioides. |
| 104c. Heads with more than 50 flowers (3-20 dm. high; flowers white, summer) | Fireweed, Erechtites hieracifolia. |
| 105a. Leaves entire, with many veins from base to apex | Indian Plantain, Cacalia tuberosa. |
| 105b. Leaves sharply serrate | Indian Plantain, Cacalia suaveolens. |
| 105c. Leaves broadly triangular or kidney-shape, sinuate or entire | Indian Plantain, Cacalia atriplicifolia. |
| 106a. Leaves united at the base (5-15 dm. high) | Boneset, Eupatorium perfoliatum. |
| 106b. Leaves sessile but not united at the base (5-15 dm. high) | Upland Boneset, Eupatorium sessilifolium. |
| 106c. Leaves petioled (4-12 dm. high) | White Snakeroot, Eupatorium urticaefolium. |
| 107a. Inflorescence ovoid or pyramidal | Joe-Pye Weed, Eupatorium purpureum. |
| 107b. Inflorescence depressed or flattened | Joe-Pye Weed, Eupatorium purpureum var. maculatum. |
| 108a. Rays yellow or brown [— 109.] | |
| 108b. Rays white to blue or red, never yellow or brown [— 197.] | |
| 109a. Principal leaves basal, the stem merely with bract-like scales [— 110.] | |
| 109b. Principal leaves on the stem, opposite or whorled [— 111.] | |
| 109c. Principal leaves on the stem, alternate, or with smaller ones clustered in their axils [— 132.] | |
| 110a. Flower-stalk 1-5 dm. high, 1-flowered (spring) | Coltsfoot, Tussilago farfara. |
| 110b. Flower-stalk 1-3 m. high, several-flowered (summer) | Prairie Dock, Silphium terebinthinaceum. |
| 111a. Ray-flowers pistillate (the 2-lobed style protrudes from their base) [— 112.] | |
| 111b. Ray-flowers with neither stamens nor pistil [— 118.] | |
| 112a. Principal leaves lobed (summer) (Leafcup) [— 113.] | |
| 112b. Principal leaves toothed or entire, not lobed [— 115.] | |
| 113a. Rays 10 or more (1-2 m. high) | Leafcup, Polymnia uvedalia. |
| 113b. Rays 5 (5-15 dm. high) [— 114.] | |
| 114a. Rays shorter than the involucre or none | Leafcup, Polymnia canadensis. |
| 114b. Rays about 1 cm. long | Leafcup, Polymnia canadensis var. radiata. |
| 115a. Stem 6 dm. high or less; pappus of slender hairs (spring) | Arnica, Arnica cordifolia. |
| 115b. Stem usually 8-20 dm. high; pappus of short scales or none (summer) [— 116.] | |
| 116a. Leaves united at base into a cup surrounding the stem | Cup Plant, Silphium perfoliatum. |
| 116b. Leaves closely sessile with a rounded base | Rosin Weed, Silphium integrifolium. |
| 116c. Leaves tapering to a short petiole; principal leaves whorled | Rosin Weed, Silphium trifoliatum. |
| 116d. Leaves abruptly rounded at the sessile base, all opposite (Ox-eye) [— 117.] | |
| 117a. Leaves smooth | Ox-eye, Heliopsis helianthoides. |
| 117b. Leaves rough | Ox-eye, Heliopsis scabra. |
| 118a. Principal stem-leaves lobed or divided [— 119.] | |
| 118b. Principal stem-leaves entire or serrate [— 127.] | |
| 119a. Submerged aquatic; leaf-segments filiform | Water Marigold, Bidens beckii. |
| 119b. Terrestrial plants; leaves merely 3-lobed (3-8 dm. high; late spring and summer) (Tickseed) [— 120.] | |
| 119c. Terrestrial plants; leaves compound or dissected (summer and autumn) [— 121.] | |
| 120a. Leaf-lobes linear-oblong, all about equal | Tickseed, Coreopsis palmata. |
| 120b. Lateral leaf-lobes very much smaller than the terminal | Tickseed, Coreopsis lanceolata. |
| 121a. Leaf-segments entire (Tickseed) [— 122.] | |
| 121b. Leaf-segments serrate (5-15 dm. high) (Tickseed Sunflower) [— 124.] | |
| 122a. Leaf-segments numerous, linear or nearly so (4-10 dm. high) [— 123.] | |
| 122b. Leaf-segments 3-5, lanceolate (1-3 m. high) | Tickseed, Coreopsis tripteris. |
| 123a. Rays yellow throughout | Tickseed, Coreopsis verticillata. |
| 123b. Rays brown, at least at the base | Tickseed, Coreopsis tinctoria. |
| 124a. Achenes wedge-shape, the inner ones less than 2 mm. wide [— 125.] | |
| 124b. Achenes obovate, the inner ones more than 2 mm. wide | Tickseed Sunflower, Bidens aristosa. |
| 125a. Leaf-lobes lanceolate | Tickseed Sunflower, Bidens trichosperma. |
| 125b. Leaf-lobes linear | Tickseed Sunflower, Bidens trichosperma var. tenuiloba. |
| 126a. Outer leaf-like bracts 10-16; achenes brown | Beggar Ticks, Bidens vulgata. |
| 126b. Outer leaf-like bracts 5-8; achenes black | Beggar Ticks, Bidens frondosa. |
| 126c. Outer leaf-like bracts about 4 | Beggar Ticks, Bidens discoidea. |
| 127a. Bracts of the involucre all essentially alike in form and texture (flowers in summer and autumn) (Sunflower) [— 179.] | |
| 127b. Bracts of the involucre in two distinct sets, differing in form or consistency or both [— 128.] | |
| 128a. Leaves entire (3-8 dm. high; late spring and summer) — 120b. | |
| 128b. Leaves serrate (late summer and autumn) (Bur Marigold) [— 129.] | |
| 129a. Rays large and conspicuous, 2-3 cm. long (3-10 dm. high) | Bur Marigold, Bidens laevis. |
| 129b. Rays 1 cm. long or less [— 130.] | |
| 130a. Outer bracts leaf-like, serrate, 3-8 cm. long (4-15 dm. high) | Bur Marigold, Bidens comosa. |
| 130b. Outer bracts 1-2.5 cm. long (2-15 dm. high) [— 131.] | |
| 131a. Heads nodding after flowering | Bur Marigold, Bidens cernua. |
| 131b. Heads permanently erect | Bur Marigold, Bidens connata. |
| 132a. Heads small, seldom more than 1 cm. wide, including the rays, blooming in late summer and autumn; flowers numerous, crowded in spikes, racemes, corymbs, or panicles (Goldenrod) [— 133.] | |
| 132b. Heads medium size or large, more than 1 cm. and usually exceeding 2 cm. in width, including the rays [— 165.] | |
| 133a. Heads chiefly in clusters or short racemes in the axils of ordinary foliage leaves, or occasionally the upper compacted into a leafy cluster terminating the stem [— 134.] | |
| 133b. Heads crowded at or near the ends of the branches at about the same distance from the base of the panicle, forming a rounded or flat-topped inflorescence [— 140.] | |
| 133c. Heads more or less uniformly distributed along the length of the branches, forming a cylindrical or pyramidal inflorescence, never flat-topped [— 146.] | |
| 134a. Stem and both sides of the leaves more or less pubescent or rough (4-10 dm. high) [— 135.] | |
| 134b. Stem and both sides of the leaves essentially smooth or with very short hairs (3-10 dm. high) [— 136.] | |
| 135a. Rays white | Goldenrod, Solidago bicolor. |
| 135b. Rays yellow | Goldenrod, Solidago hispida. |
| 136a. Basal leaves abruptly narrowed to winged petioles [— 137.] | |
| 136b. Basal leaves not abruptly narrowed to winged petioles [— 138.] | |
| 137a. Involucre 2-5 mm. long | Goldenrod, Solidago latifolia. |
| 137b. Involucre 8-12 mm. long | Goldenrod, Solidago macrophylla. |
| 138a. Lower leaves broadly oval, obtuse, thickish, crenate; achenes glabrous | Goldenrod, Solidago erecta. |
| 138b. Lower leaves lanceolate, acuminate, thin, sharply serrate; achenes hairy [— 139.] | |
| 139a. Stem usually simple; heads few in very small clusters | Goldenrod, Solidago caesia var. axillaris. |
| 139b. Stem usually diffusely branched; heads numerous | Goldenrod, Solidago caesia. |
| 140a. Lower leaves ovate, oblong, or oval, pinnately veined (5-15 dm. high) [— 141.] | |
| 140b. Lower leaves linear-lanceolate. 3-5-veined (3-12 dm. high) [— 142.] | |
| 141a. Stem and leaves rough-hairy | Goldenrod, Solidago rigida. |
| 141b. Stem and leaves smooth | Goldenrod, Solidago ohioensis. |
| 142a. Heads very few in a small cluster; leaves few and scattered | Goldenrod, Solidago houghtonii. |
| 142b. Heads very many, in a large cluster; stem very leafy [— 143.] | |
| 143a. Leaves hairy | Goldenrod, Solidago graminifolia var. nuttallii. |
| 143b. Leaves smooth [— 144.] | |
| 144a. Leaves folded, 8-20 mm. wide | Goldenrod, Solidago riddellii. |
| 144b. Leaves flat, 1-8 mm. wide [— 145.] | |
| 145a. Leaves 4-8 mm. wide, distinctly 3-5-ribbed | Goldenrod, Solidago graminifolia. |
| 145b. Leaves 1-4 mm. wide, usually with 1 mid-vein | Goldenrod, Solidago tenuifolia. |
| 146a. Only 2-5 stem-leaves below the inflorescence (1-3 dm. high) | Goldenrod, Solidago cutleri. |
| 146b. Stem-leaves numerous [— 147.] | |
| 147a. Basal leaves much larger than the greatly reduced or bract-like upper ones [— 148.] | |
| 147b. Leaves essentially uniform in size from base to summit of stem [— 157.] | |
| 148a. Racemes or branches of the panicle either short and arranged along a more or less elongated central axis, or elongated and ascending, scarcely recurved, forming a narrow, more or less elongated panicle [— 149.] | |
| 148b. Racemes or branches of the panicle usually elongated, spreading outwards, usually recurved, forming a widened panicle [— 153.] | |
| 149a. Leaves mostly entire, the upper ones with smaller leaves fascicled in the axils (5-20 dm. high) | Goldenrod, Solidago speciosa. |
| 149b. Leaves mostly serrate, at least the basal ones [— 150.] | |
| 150a. Heads on pedicels 5-15 mm. long; achenes pubescent; stems usually clustered (1-5 dm. high, or prostrate) [— 151.] | |
| 150b. Heads on pedicels not over 5 mm. long; achenes smooth or nearly so; stems usually single (6-12 dm. high) [— 152.] | |
| 151a. Basal leaves 7-12 cm. long | Goldenrod, Solidago racemosa. |
| 151b. Basal leaves 15-30 cm. long | Goldenrod, Solidago racemosa var. gillmani. |
| 152a. Leaves pinnately veined | Goldenrod, Solidago uliginosa. |
| 152b. Leaves 3-5-ribbed | Goldenrod, Solidago neglecta. |
| 153a. Both sides of the leaf pubescent or rough [— 154.] | |
| 153b. Leaf not pubescent or rough on both sides [— 155.] | |
| 154a. Stem closely pubescent (2-8 dm. high) | Goldenrod, Solidago nemoralis. |
| 154b. Stem glabrous (5-12 dm. high) | Goldenrod, Solidago juncea var. scabrella. |
| 155a. Leaves rough above, smooth below (6-15 dm. high) | Goldenrod, Solidago patula. |
| 155b. Leaves smooth on both sides (5-12 dm. high) [— 156.] | |
| 156a. Branches of the panicle spreading or recurved | Goldenrod, Solidago juncea. |
| 156b. Branches of the panicle upright | Goldenrod, Solidago juncea var. ramosa. |
| 157a. Stem more or less pubescent or hairy throughout (5-20 dm. high) [— 158.] | |
| 157b. Stem smooth, at least below the inflorescence [— 161.] | |
| 158a. Involucre 2-2.7 mm. long | Goldenrod, Solidago canadensis. |
| 158b. Involucre 3-5 mm. long [— 159.] | |
| 159a. Leaves pinnately veined, scabrous above | Goldenrod, Solidago rugosa. |
| 159b. Leaves 3-5-ribbed, pubescent but not scabrous above [— 160.] | |
| 160a. Stem and lower side of leaves covered with short hairs; common species | Goldenrod, Solidago altissima. |
| 160b. Stem and lower side of leaves with distinct, loose, soft hairs (shore of Lake Superior) | Goldenrod, Solidago altissima var. procera. |
| 161a. Involucre 2-2.7 mm. long (5-20 dm. high) — 158a. | |
| 161b. Involucre 3-6 mm. long [— 162.] | |
| 162a. Racemes or branches of the panicle either short and arranged along a more or less elongated axis, or elongated and ascending, scarcely recurved, forming a narrow more or less elongated panicle (5-10 dm. high) | Goldenrod, Solidago speciosa var. angustata. |
| 162b. Racemes or branches of the panicle usually elongated, spreading outward, usually recurved, forming a widened panicle; leaves distinctly serrate [— 163.] | |
| 163a. Leaves pinnately veined (5-12 dm. high) | Goldenrod, Solidago ulmifolia. |
| 163b. Leaves 3-5-ribbed (5-20 dm. high) [— 164.] | |
| 164a. Leaves glabrous on both sides | Goldenrod, Solidago serotina. |
| 164b. Leaves slightly pubescent beneath | Goldenrod, Solidago serotina var. gigantea. |
| 165a. Ray-flowers pistillate (the 2-lobed style protrudes from their base) [— 166.] | |
| 165b. Ray-flowers with neither stamens nor pistil [— 174.] | |
| 166a. Principal leaves more than 2 dm. long (1-3 m. high; summer) [— 167.] | |
| 166b. Principal leaves less than 1.5 dm. long [— 168.] | |
| 167a. Leaves deeply lobed | Compass Plant, Silphium laciniatum. |
| 167b. Leaves toothed or serrate | Elecampane, Inula helenium. |
| 168a. Leaves narrowly linear (3-6 dm. high; late summer) | Sneezeweed, Helenium tenuifolium. |
| 168b. Leaves of a broader shape [— 169.] | |
| 169a. Heads 1-2 cm. wide; flowers in spring and early summer (2-8 dm. high) (Ragwort) [— 170.] | |
| 169b. Heads 2-5 cm. wide; flowers in late summer and autumn [— 173.] | |
| 170a. Basal leaves cordate at base | Ragwort, Senecio aureus. |
| 170b. Basal leaves narrowed to the base [— 171.] | |
| 171a. Basal leaves obovate | Ragwort, Senecio obovatus. |
| 171b. Basal leaves oblong | Ragwort, Senecio balsamitae. |
| 172a. Introduced annual in waste places (1-4 dm. high; spring and summer) | Groundsel, Senecio vulgaris. |
| 172b. Native biennial in moist ground (3-8 dm. high; summer) | Squaw Weed, Senecio discoideus. |
| 173a. Leaves 2-5 cm. long, sharply spinulose-serrate; involucre viscid (3-6 dm. high; summer) | Gum Plant, Grindelia squarrosa. |
| 173b. Leaves 5-12 cm. long, merely serrate; involucre gray-pubescent (5-15 dm. high; late summer) | Sneeze Weed, Helenium autumnale. |
| 174a. Disk hemispherical or oblong-cylindrical (Summer) [— 175.] | |
| 174b. Disk flat or somewhat convex (Sunflower) (summer and autumn) [— 179.] | |
| 175a. Disk yellow or greenish-yellow (1-3 dm. high) [— 176.] | |
| 175b. Disk gray-brown or purple (5-15 dm. high) [— 177.] | |
| 176a. Principal stem-leaves pinnately divided | Golden Glow, Rudbeckia laciniata. |
| 176b. Principal stem-leaves merely serrate | Yellow Ironweed, Actinomeris alternifolia. |
| 177a. Rays drooping; leaves pinnately divided | Gray-headed Coneflower, Lepachys pinnata. |
| 177b. Rays spreading when in bloom [— 178.] | |
| 178a. Lower leaves deeply 3-lobed | Coneflower, Rudbeckia triloba. |
| 178b. Stem-leaves sharply serrate | Coneflower, Rudbeckia speciosa var. sullivantii. |
| 178c. Stem-leaves entire or sparingly serrate | Black-eyed Susan, Rudbeckia hirta. |
| 179a. Disk-flowers brown or purple [— 180.] | |
| 179b. Disk-flowers yellow [— 182.] | |
| 180a. Stem-leaves ovate or ovate-lanceolate; petioles prominent, not winged [— 181.] | |
| 180b. Stem-leaves ovate or ovate-lanceolate, contracted at the base into a winged petiole (6-15 dm. high) | Sunflower, Helianthus atrorubens. |
| 180c. Stem-leaves oblong-lanceolate, very thick and rigid, gradually narrowed to a sessile or short-petioled base (5-20 dm. high) | Sunflower, Helianthus scaberrimus. |
| 181a. Disk less than 2 cm. wide (3-10 dm. high) | Sunflower, Helianthus petiolaris. |
| 181b. Disk more than 2.5 cm. wide (1-3 m. high) | Sunflower, Helianthus annuus. |
| 182a. Leaves all or chiefly at the base (5-10 dm. high) | Sunflower, Helianthus occidentalis. |
| 182b. Leaves chiefly scattered on the stem [— 183.] | |
| 183a. Leaves mainly or all alternate, and not definitely 3-ribbed (1-4 m. high) [— 184.] | |
| 183b. Leaves mainly or all opposite, lanceolate to ovate, and 3-ribbed [— 186.] | |
| 184a. Stem glabrous | Sunflower, Helianthus grosse-serratus. |
| 184b. Stem hairy or rough [— 185.] | |
| 185a. Leaves hairy beneath, rough above, lanceolate | Sunflower, Helianthus giganteus. |
| 185b. Leaves rough on both sides, elongated | Sunflower, Helianthus maximiliani. |
| 186a. Leaves sessile (5-15 dm. high) [— 187.] | |
| 186b. Leaves petioled, or narrowed at the base into a petiole (5-30 dm. high) [— 189.] | |
| 187a. Leaves wedge-shape at the base | Sunflower, Helianthus doronicoides. |
| 187b. Leaves rounded at the base [— 188.] | |
| 188a. Stem glabrous or nearly so | Sunflower, Helianthus divaricatus. |
| 188b. Stem densely and softly hirsute | Sunflower, Helianthus mollis. |
| 189a. Stems rough, pubescent, or hispid [— 190.] | |
| 189b. Stems glabrous or nearly so [— 193.] | |
| 190a. Leaves narrowly lanceolate, more than 5 times as long as wide | Sunflower, Helianthus giganteus var. subtuberosus. |
| 190b. Leaves ovate-lanceolate, not more than 4 times as long as wide [— 191.] | |
| 191a. Leaves rounded at base, above the petiole | Sunflower, Helianthus hirsutus. |
| 191b. Leaves narrowed to the base [— 192.] | |
| 192a. Bracts of the involucre spreading | Jerusalem Artichoke, Helianthus tuberosus. |
| 192b. Bracts all appressed | Sunflower, Helianthus laetiflorus. |
| 193a. Heads 3 cm. wide or less, including the rays | Sunflower, Helianthus microcephalus. |
| 193b. Heads 4 cm. wide or more, including the rays [— 194.] | |
| 194a. Leaves narrowed at the base into a winged petiole [— 195.] | |
| 194b. Petiole slender, not winged | Sunflower, Helianthus decapetalus. |
| 195a. Leaves green on both sides; bracts longer than the disk | Sunflower, Helianthus tracheliifolius. |
| 195b. Leaves paler below than above; bracts not longer than the disk [— 196.] | |
| 196a. Leaves minutely pubescent beneath | Sunflower, Helianthus strumosus. |
| 196b. Leaves conspicuously downy beneath | Sunflower, Helianthus strumosus var. mollis. |
| 197a. Leaves all basal, the flowers on scaly stalks (2-8 dm. high; flowers whitish, in spring) | Coltsfoot, Petasites palmata. |
| 197b. Stem-leaves present, opposite [— 198.] | |
| 197c. Stem-leaves present, alternate [— 200.] | |
| 198a. Leaves ovate, dentate, 2-6 cm. long (2-8 dm. high; summer) (Galinsoga) [— 199.] | |
| 198b. Leaves lobed, 10-25 cm. long — 113b. | |
| 199a. Pubescence sparse, appressed | Galinsoga, Galinsoga parviflora. |
| 199b. Pubescence abundant, spreading | Galinsoga, Galinsoga parviflora var. hispida. |
| 200a. Leaves dissected or deeply lobed or pinnatifid; pappus never capillary; rays white to pink (3-10 dm. high; summer and autumn) [— 201.] | |
| 200b. Leaves entire or serrate [— 206.] | |
| 201a. Heads 4-8 mm. wide (Yarrow) [— 202.] | |
| 201b. Heads 12-50 mm. wide [— 203.] | |
| 202a. Flower-clusters flat-topped | Yarrow, Achillea millefolium. |
| 202b. Flower-clusters very convex | Yarrow, Achillea lanulosa. |
| 203a. Principal leaves pinnatifid — 213a. | |
| 203b. Principal leaves 1-3 times pinnately parted or dissected [— 204.] | |
| 204a. Leaf-segments very narrowly linear; leaves 2-3-pinnate [— 205.] | |
| 204b. Leaf-segments linear or lanceolate; heads 2.5-5 cm. wide | Camomile, Anthemis arvensis. |
| 204c. Leaf-segments ovate to ovate-oblong; heads 1-2 cm. wide | Feverfew, Chrysanthemum parthenium. |
| 205a. Foliage strongly scented | Dog Fennel, Anthemis cotula. |
| 205b. Foliage not ill-scented | Wild Camomile, Matricaria inodora. |
| 206a. Heads 3-6 mm. broad, including the rays (summer and autum) [— 207.] | |
| 206b. Heads 7 mm. broad or larger, including the rays [— 209.] | |
| 207a. Rays purple (1-4 dm. high) | Horse Weed, Erigeron divaricatus. |
| 207b. Rays white [— 208.] | |
| 208a. Leaves obovate to oblong (3-10 dm. high) — 135a. | |
| 208b. Leaves linear or narrowly lanceolate (2-25 dm. high) | Horse Weed, Erigeron canadensis. |
| 209a. Pappus none, or minute and not of hairs (summer and autumn) [— 210.] | |
| 209b. Pappus of hairs [— 214.] | |
| 210a. Disk-flowers purple or brown (4-12 dm. high; rays pink) (Purple Coneflower) [— 211.] | |
| 210b. Disk-flowers yellow or nearly white [— 212.] | |
| 211a. Leaves ovate or ovate-lanceolate, most of them serrate | Purple Coneflower, Brauneria purpurea. |
| 211b. Leaves narrowly lanceolate, gradually narrowed at the base, entire | Purple Coneflower, Brauneria pallida. |
| 212a. Rays broadly obovate; heads 1-2 cm. wide (3-6 dm. high) | Sneezewort, Achillea ptarmica. |
| 212b. Rays oblong or narrowly elliptical [— 213.] | |
| 213a. Leaves serrate (3-10 dm. high) | Ox-eye Daisy, Chrysanthemum leucanthemum var. pinnatifidum. |
| 213b. Leaves entire (8-25 dm. high) | Boltonia, Boltonia asteroides. |
| 214a. Involucral bracts all the same length or nearly so and narrow, or with a few short outer ones; plants blooming in spring and summer, or a few plants persisting in bloom until autumn (Fleabane) [— 215.] | |
| 214b. Involucral bracts unequal, the outer successively shorter (or rarely nearly equal), loosely or closely overlapping; plants 3-15 dm. high, blooming in late summer and autumn (Aster) [— 221.] | |
| 215a. Rays short and inconspicuous, barely longer than the pappus (1-5 dm. high; summer) | Fleabane, Erigeron acris var. asteroides. |
| 215b. Rays conspicuous, spreading, 3 mm. long or more [— 216.] | |
| 216a. Rare plants of the Northern Peninsula, with entire leaves and stems 1-5 dm. high, from a thick woody root (flowers white or purple, summer) [— 217.] | |
| 216b. Common species, with erect stems from fibrous roots; leaves toothed (except in one species) [— 218.] | |
| 217a. Heads 3-5 cm. wide; rays about 100 | Fleabane, Erigeron glabellus. |
| 217b. Heads 1-2 cm. wide; rays 20-30 | Fleabane, Erigeron hyssopifolius. |
| 218a. Stem unbranched, except for the peduncles; leaves chiefly basal; heads 1-9 (2-5 dm. high; flowers pale-purple, spring) | Fleabane, Erigeron pulchellus. |
| 218b. Stem branched; principal leaves on the stem; heads usually numerous (3-12 dm. high; spring and summer) [— 219.] | |
| 219a. Stem-leaves linear, entire | Fleabane, Erigeron ramosus. |
| 219b. Stem-leaves ovate-lanceolate, the principal ones toothed [— 220.] | |
| 220a. Rays 100 or more, light-purple or pink | Fleabane, Erigeron philadelphicus. |
| 220b. Rays much fewer, white | Fleabane, Erigeron annuus. |
| 221a. Basal leaves petioled and heart-shape at the base [— 222.] | |
| 221b. Basal leaves not petioled; stem-leaves with heart-shape clasping bases [— 231.] | |
| 221c. Basal and stem-leaves sessile or petioled, but never heart-shape or clasping [— 240.] | |
| 222a. Rays white or violet [— 223.] | |
| 222b. Rays blue [— 225.] | |
| 223a. Plant glandular, especially on the pedicels and branches of the inflorescence | Aster, Aster macrophyllus. |
| 223b. Plant not glandular [— 224.] | |
| 224a. Leaves rough above | Aster, Aster schreberi. |
| 224b. Leaves smooth above | Aster, Aster divaricatus. |
| 225a. Stem-leaves clasping the stem by a cordate base | Aster, Aster undulatus. |
| 225b. Stem-leaves not cordate-clasping [— 226.] | |
| 226a. Leaves entire [— 227.] | |
| 226b. Leaves serrate [— 228.] | |
| 227a. Leaves glabrous above | Aster, Aster shortii. |
| 227b. Leaves rough above | Aster, Aster azureus. |
| 228a. Involucre 4-6 mm. long [— 229.] | |
| 228b. Involucre 6-10 mm. long [— 230.] | |
| 229a. Leaves rough; petioles mostly winged | Aster, Aster lowrieanus. |
| 229b. Leaves smooth; petioles slender, not winged | Aster, Aster cordifolius. |
| 230a. Heads few, seldom more than 10, in a loose spreading cluster | Aster, Aster lindleyanus. |
| 230b. Heads numerous, in a rather elongate crowded cluster | Aster, Aster sagittifolius. |
| 231a. Stem hirsute or rough-pubescent [— 232.] | |
| 231b. Stem smooth, or essentially so [— 236.] | |
| 232a. Leaves conspicuously serrate | Aster, Aster puniceus. |
| 232b. Leaves entire or nearly so [— 233.] | |
| 233a. Leaves narrowed toward the base and barely clasping, linear or oblong-linear [— 234.] | |
| 233b. Leaves ovate-oblong or lanceolate, with a broad conspicuously clasping base [— 235.] | |
| 234a. Involucre pubescent but not glandular | Aster, Aster amethystinus. |
| 234b. Involucre glandular | Aster, Aster oblongifolius. |
| 235a. Involucre very glandular and viscid; rays very numerous, violet-purple; leaves lanceolate | Aster, Aster novae-angliae. |
| 235b. Involucre slightly glandular or not at all; rays 20-30, generally blue-purple; leaves ovate-oblong | Aster, Aster patens. |
| 236a. Leaves of a linear type [— 237.] | |
| 236b. Leaves broader than linear, at least 1 cm. wide [— 238.] | |
| 237a. Bracts narrow, approximately equal in length — 253a. | |
| 237b. Bracts of several lengths, the outer successively shorter — 256a. | |
| 238a. Leaves smooth above | Aster, Aster laevis. |
| 238b. Leaves rough above [— 239.] | |
| 239a. Leaves contracted below the middle and then abruptly dilated to the clasping base | Aster, Aster prenanthoides. |
| 239b. Leaves gradually narrowed toward the base | Aster, Aster puniceus. |
| 240a. Rays conspicuous [— 241.] | |
| 240b. Rays minute or wanting | Aster, Aster angustus. |
| 241a. Stems and leaves gray with a silky pubescence | Aster, Aster sericeus. |
| 241b. Stem and leaves green, not silky [— 242.] | |
| 242a. Bracts glandular-viscid; rays violet | Aster, Aster oblongifolius. |
| 242b. Bracts bristly-ciliate [— 243.] | |
| 242c. Bracts smooth or pubescent, not glandular or bristly-ciliate [— 244.] | |
| 243a. Leaves crowded, rigid; rays white | Aster, Aster multiflorus. |
| 243b. Leaves not crowded and rigid; rays blue — 234a. | |
| 244a. Bracts narrowed at the tip into thickened firm green awl-shape points [— 245.] | |
| 244b. Bracts acute or obtuse at the flattened tip [— 247.] | |
| 245a. Involucre 4-5 mm. long [— 246.] | |
| 245b. Involucre 7-8 mm. high | Aster, Aster polyphyllus. |
| 246a. Stem smooth | Aster, Aster ericoides. |
| 246b. Stem hairy; leaves linear | Aster, Aster ericoides var. villosus. |
| 246c. Stem densely white-woolly | Aster, Aster ericoides var. platyphyllus. |
| 247a. Leaves at most 4.5 cm. long [— 248.] | |
| 247b. Leaves larger, at least the principal ones [— 249.] | |
| 248a. Stems in clusters; leaves rigid, linear, with 1 vein; flowers blue | Aster, Aster linariifolius. |
| 248b. Stem solitary; leaves not rigid; flowers rose-pink | Aster, Aster nemoralis. |
| 249a. Heads solitary at the end of minutely leafy branchlets; leaves linear | Aster, Aster dumosus. |
| 249b. Heads in flat-topped clusters; leaves lanceolate or broader [— 250.] | |
| 249c. Heads in more or less one-sided racemes [— 251.] | |
| 249d. Heads in panicles or irregular clusters [— 253.] | |
| 250a. Leaves rigid, linear-lanceolate | Aster, Aster ptarmicoides. |
| 250b. Leaves not rigid, lanceolate | Aster, Aster umbellatus. |
| 251a. Leaves lanceolate, sharply serrate [— 252.] | |
| 251b. Leaves linear or narrowly linear-lanceolate, only the larger ones with a few teeth near the middle | Aster, Aster vimineus. |
| 252a. Stem glabrous or somewhat pubescent | Aster, Aster lateriflorus. |
| 252b. Stem woolly with long hairs | Aster, Aster lateriflorus var. hirsuticaulis. |
| 253a. Bracts narrow, approximately equal in length | Aster, Aster longifolius. |
| 253b. Bracts of several lengths, the outer successively shorter [— 254.] | |
| 254a. Heads 10-15 mm. wide, including the rays | Aster, Aster tradescanti. |
| 254b. Heads 15-25 mm. wide, including the rays [— 255.] | |
| 255a. Bracts with conspicuous dilated or subrhombic tips | Aster, Aster salicifolius. |
| 255b. Bracts without conspicuous green tips [— 256.] | |
| 256a. Rays purple or rose; bog plant with linear leaves | Aster, Aster junceus. |
| 256b. Rays white, or slightly tinged with blue; leaves oblong to narrowly lanceolate | Aster, Aster paniculatus. |
GLOSSARY
Achene. A small, dry, hard, seed-like fruit containing a single seed.
Acuminate. Taper-pointed.
Acute. Ending with an acute angle.
Alternate. Located singly on the stem, with other leaves above or below.
Annual. Living but a single season.
Anther. The (usually) enlarged end of a stamen, bearing the pollen.
Ascending. Rising or curving obliquely upward.
Auricle. An ear-shape appendage at the base of a leaf or other organ.
Auricled, auriculate. Furnished with auricles.
Awl-shape. Tapering to a slender stiff point.
Awn. An awl-shape or bristle-shape appendage.
Axil. The point on a stem just above the base of a leaf or branch.
Axillary. Arising from or produced in the axil.
Basal. Arising from or produced at the base.
Beak. Ending in a prominent slender point.
Bract. A small leaf near the base of a flower or flower-stalk, or in a flower-cluster.
Bracteal. An adjective derived from bract.
Bipinnate. A leaf with a pinnately branched axis, bearing leaflets on the sides of the branches.
Calyx. The outer portion of the flower, usually green in color. In some plants it is colored to resemble (or replace) the corolla, and in others may be minute or wanting.
Capitate. Shaped like a head; or arranged in a dense compact cluster.
Capsule. A dry fruit with usually several seeds, opening at maturity.
Catkin. A cylindrical or ovoid cluster of inconspicuous flowers, for example, the "pussy willow."
Cells of ovary. The cavity or cavities within an ovary, in which the seeds are produced.
Ciliate. Provided with hairs at the margin.
Clasping. With the base of a leaf or other organ wholly or partly surrounding the stem.
Cleft. Deeply divided toward the base or the mid-rib.
Closed sheath. A leaf-sheath in which the margins are united to form a tube.
Composite. A flower-cluster containing several or many small flowers, closely crowded together and provided with calyx-like bracts, so that the whole cluster resembles a single flower.
Compound. Composed of 2 or more similar parts united, as a compound ovary.
Compound leaf. A leaf with two or more separate leaflets on a single petiole.
Connate. Grown together.
Cordate. Heart-shape. A whole leaf-blade may be cordate, or the term may be applied to the base of a leaf only.
Cordate-sagittate. Intermediate in shape between cordate and sagittate.
Corm. An enlarged stem-base, of solid structure and usually underground.
Corolla. The portion of a flower next to the calyx (in ordinary cases). It is generally the most conspicuous part of the flower, but may be completely absent, or inconspicuous, or replaced by the calyx.
Corymb. A flat-topped or convex-topped flower-cluster.
Creeping. With stems prostrate on the ground and rooting at intervals.
Crenate. With round-pointed teeth at the margin.
Crenulate. Finely or minutely crenate.
Cuspidate. Ending with a short sharp stiff point.
Deciduous. Not persistent for a long time; not evergreen.
Decompound. Repeatedly branched with numerous leaflets.
Decurrent. Extending with wing-like expansions down the stem.
Decumbent. A stem prostrate at the base, but with the tip more or less ascending.
Dehiscent. Breaking open at maturity to discharge the contents.
Deltoid. Broadly triangular.
Dioecious. Bearing staminate and pistillate flowers upon separate plants.
Dissected. Finely divided into numerous small or narrow segments.
Divided. With deep segments or lobes.
Elliptical. Having the shape of an ellipse.
Elliptical-lanceolate. Intermediate in shape between elliptical and lanceolate.
Entire. With an unbroken margin, without teeth or lobes.
Epiphyte. A plant growing attached to the bark of another plant, and without connection with the soil.
Erect. Growing in nearly or quite a vertical position.
Evenly pinnate. A compound leaf terminating in a pair of leaflets.
Filament. The (usually) slender basal portion of a stamen, supporting the anther at its tip.
Floweret. A small flower.
Gamopetalous. Composed of united petals.
Gamosepalous. Composed of united sepals.
Glabrous. Smooth; without hairs.
Glandular. Bearing glands.
Glaucous. Covered with a thin bluish or whitish deposit, easily rubbed off.
Glume. A bract at the base of a spikelet of a grass.
Half recurved. Curved half-way backward.
Hastate. Shaped like an arrow-head, but with the basal lobes pointing outwards instead of backward.
Head. A dense cluster of flowers, about as broad as long.
Hirsute. With stiff coarse hairs.
Imperfect. Flowers which contain either pistil or stamens, not both.
Incised. With deep, sharp, irregular, divisions.
Indehiscent. Not breaking open at maturity to discharge the contents.
Inflorescence. A cluster of flowers.
Internode. A section of stem between two joints, or nodes.
Involucre. A collection of bracts at the base of a flower-cluster.
Irregular. Possessing similar parts of different size or form. An irregular flower is generally distinguished by petals of unequal size or shape.
Laciniate. Cut into narrow pointed lobes or divisions.
Lanceolate. Shaped like a lance-head, several times longer than wide,
and broadest below the middle.
Linear. Long and narrow, but with about uniform width.
Linear-lanceolate. Intermediate in shape between linear and lanceolate;
narrowly lanceolate.
Lip. The largest and most conspicuous petal in an irregular corolla,
usually applied to the lower petal of an orchid.
Lobe. A segment or division of any organ.
Leaflet. One portion of the blade of a compound leaf.
Lemma. One of the bracts in the spikelet of a grass, and described in the treatment of that family.
Membranous. Thin or membrane-like in texture.
Monoecious. Bearing stamens and pistils in separate flowers, but on the same plant.
Mucronate. Tipped with a short small abrupt tip.
Node. A joint of a stem, at which leaves are borne and branches appear.
Oblanceolate. Reversed lanceolate in shape.
Oblique. With unequal sides.
Oblong. Somewhat rectangular in shape, with parallel sides.
Oblong-lanceolate. Intermediate in shape between oblong and lanceolate.
Oblong-spatulate. Intermediate in shape between oblong and spatulate.
Obovate. Reversed ovate in shape.
Obtuse. Blunt-tipped; terminating in an obtuse angle.
Odd-pinnate. A compound leaf terminating in a single leaflet.
Once-compound. A compound leaf bearing leaflets at the end or along the sides of the main axis.
Once-pinnate. A compound leaf bearing leaflets along the sides of the axis.
Open sheath. A leaf-sheath with separate margins.
Opposite. Situated in pairs on opposite sides of the stem or axis.
Ovary. The basal, usually swollen portion of the pistil, within which the seeds are produced.
Ovate. Egg-shape in outline.
Ovate-lanceolate. Intermediate in shape between ovate and lanceolate; broadly lanceolate or narrowly ovate.
Ovate-oblong. Intermediate in shape between ovate and oblong.
Ovoid. Egg-shape.
Palmate. With several organs or structures attached at or proceeding from the same point; applied chiefly to the arrangement of principal veins in a leaf and of leaflets in a compound leaf.
Panicle. A loose, more or less irregular, branching cluster of pedicelled flowers, usually much longer than thick.
Parallel-veined. With the principal veins of the leaf paralleling each other from the base to the apex, or (rarely) from the mid-rib to the margin.
Pedicel. The stalk of a single flower.
Parasite. A plant which grows attached to another and derives its nourishment from it.
Peduncle. The stalk of a flower-cluster, or of a solitary flower.
Peltate. Attached to the stalk by the lower surface, instead of the margin.
Perennial. Living through several seasons.
Perfect. Bearing stamens and pistils in the same flower.
Perfoliate. Clasping the stem so completely that the stem seems to pass through it.
Perianth. The calyx and corolla of a flower.
Perigynium. A sac-like structure surrounding the achene of a sedge.
Persistent. Remaining attached for a considerable time.
Petal. One member or segment of the corolla.
Petiole. The stalk of a leaf.
Pinnate. With several organs or structures attached at the sides of an axis or stalk; applied chiefly to the arrangement of the principal veins in a leaf and of leaflets in a compound leaf.
Pinnatifid. Deeply pinnately cut or divided.
Pistil. The central portion of a flower, consisting of ovary, style, and stigma; the seed-bearing part of the flower.
Pistillate. Bearing pistils.
Polygamous. Applied to plants in which some flowers are perfect and others either staminate or pistillate.
Pubescent. Hairy.
Raceme. A more or less elongated flower-cluster, bearing pedicelled flowers along a single axis.
Racemose. Arranged in racemes.
Receptacle. The end of a peduncle or pedicel upon which the organs of a flower, or the flowers of a head, are attached.
Recurved. Curved back.
Reflexed. Abruptly bent back or down.
Regular. Uniform in shape or structure. Flowers are generally considered regular when all the petals are of the same size and shape.
Retrorse. Directed backward or downward.
Revolute. Rolled backward or under.
Rootstock. A horizontal subterranean stem, sending up leaves or stems.
Rotate. Wheel-shape; essentially flat and circular.
Sac-like. Inflated; sack-like.
Sagittate. Shaped like an arrow-head.
Salver-form. A corolla having a slender tube abruptly expanded at the summit into a flat or spreading portion.
Scape. A peduncle arising directly from the base of the plant, leafless or bearing bracts only.
Segment. One member or portion of an organ.
Sepal. One member or portion of the calyx.
Serrate. With sharp teeth at the margin.
Serrulate. Finely or minutely serrate.
Sessile. Without a stalk, petiole, or pedicel.
Sheathing. Inclosing.
Simple. In one piece; not compound; usually applied to leaves with a single blade.
Sinuate. Wavy-margined.
Sinus. The angle between two lobes or divisions.
Spadix. A short fleshy spike.
Spathe. A large bract or pair of bracts enclosing a flower-cluster.
Spatulate. Shaped like a spatula, with a narrow base and an enlarged, more or less rounded summit.
Spike. An elongated flower-cluster having sessile flowers upon an unbranched axis.
Spike-like. Resembling a spike.
Spinulose-serrate. Provided with teeth tipped with minute spines.
Spur. A hollow projection from the calyx or corolla, usually slender in shape, and generally directed backward.
Stamen. One of the organs of a flower, consisting of a filament and anther.
Staminate. Bearing stamens.
Stolon. A short stem arising from the base of a plant, prostrate or nearly so, and eventually taking root.
Striate. Marked with fine stripes or ridges.
Style. A portion of the pistil, usually slender, and connecting the ovary and stigma.
Superior. A superior ovary occupies the center of the flower and is not attached to any other floral organs.
Subtending. Situated at the base of an organ.
Subulate. Awl-shape.
Ternately. Divided by threes.
Tomentose. Densely hairy with matted or tangled hairs.
Trifoliate. With three leaflets.
Truncate. Cut straight across at the tip, or nearly so.
Tube. The more or less cylindrical portion of a gamosepalous calyx or a gamopetalous corolla, distinguished from the expanded or lobed terminal portion.
Tubular. Shaped like a tube.
Twice-pinnate. Same as bipinnate.
Two-lipped. A calyx or corolla in which the upper half is decidedly different in size or shape from the lower.
Umbel. A flower-cluster with several or many pedicelled flowers all arising from the same point.
Undulate. With a wavy margin.
Viscid. Sticky.
Villous. With long soft hairs.
Whorl. An arrangement of 3 or more leaves or flowers in a circle around a node.
Whorled. In a whorl.
Wing. A thin flat expansion on the sides or edge of an organ.
INDEX
Abies, [1]
Abutilon, [72]
Acalypha, [66]
Acanthaceae, [107]
Acanthus Family, [107]
Acer, [70]
Aceraceae, [70]
Acerates, [90]
Achillea, [130], [131]
Acnida, [30]
Acorus, [8]
Actaea, [39]
Actinomeris, [128]
Adder's Mouth, [17]
Adenocaulon, [118]
Adlumia, [41]
Aesculus, [70]
Agastache, [97]
Agrimonia, [55]
Agrimony, [55]
Agropyron, [6]
Agrostemma, [33]
Agrostis, [6]
Ailanthus, [65]
Aizoaceae, [31]
Alder, [22]
Alder, Black, [69]
Aletris, [13]
Alfalfa, [61]
Alisma, [3]
Alismaceae, [3]
Allium, [13]
Alnus, [22]
Alopecurus, [4]
Alsike Clover, [61]
Althaea, [72]
Alum Root, [50], [51]
Alyssum, [42], [46]
Alyssum, Yellow, [42], [46]
Amaranth Family, [30]
Amaranthaceae, [30]
Amaranthus, [30]
Amaryllidaceae, [14]
Amaryllis Family, [14]
Ambrosia, [114]
Amelanchier, [55]
American Columbo, [88]
American Ipecac, [57]
Ammophila, [4]
Amorpha, [58]
Amphicarpa, [59]
Anacardiaceae, [68]
Anagallis, [87]
Anaphalis, [120]
Andromeda, [86]
Andropogon, [5]
Androsace, [87]
Anemone, [38], [39]
Anemone, Rue, [39]
Anemone, Wood, [38]
Anemonella, [39]
Angelica, [82]
Anonaceae, [40]
Antennaria, [120]
Anthemis, [130]
Antirrhinum, [103]
Anychia, [31]
Apios, [58]
Aplectrum, [16]
Apocynaceae, [90]
Apocynum, [90]
Appalachian Cherry, [54]
Apple, [54]
Apple of Peru, [101]
Aquifoliaceae, [69]
Aquilegia, [36]
Arabis, [46], [47]
Araceae, [8]
Aralia, [80]
Araliaceae, [80]
Arbutus, Trailing, [85]
Arceuthobium, [25]
Arctium, [117]
Arctostaphylos, [85]
Arenaria, [32]
Arethusa, [16]
Arisaema, [8]
Aristolochia, [25]
Aristolochiaceae, [25]
Arnica, [123]
Arrow Arum, [9]
Arrow Grass, [3]
Arrow Grass Family, [3]
Arrow-head, [3]
Arrow Wood, [111]
Artemisia, [119]
Artichoke, Jerusalem, [129]
Arum Family, [8]
Asarum, [25]
Asclepias, [90], [91]
Asclepiadaceae, [90]
Ash, [88]
Ash, Mountain, [52]
Ash, Prickly, [65]
Asimina, [40]
Asparagus, [10]
Aspen, [19]
Aster, [132]-[134]
Atriplex, [29]
Avena, [6]
Avens, [56], [57]
Baby's Breath, [34]
Balm of Gilead, [19]
Balsam, [1]
Balsam Poplar, [19]
Balsaminaceae, [71]
Baneberry, [39]
Baptisia, [61]
Barbarea, [44]
Barberry, [40]
Barberry Family, [40]
Barnyard Grass, [5]
Barren Strawberry, [55]
Bartonia, [88]
Basil, [97]
Basil-thyme, [97]
Basswood, [72]
Bayberry, [21]
Beach Grass, [4]
Beach Pea, [59]
Beaked Hazel, [22]
Bearberry, [85]
Beard Grass, [5]
Beard-tongue, [104]
Bedstraw, [108], [109]
Beech, [22]
Beech Drops, [84], [106]
Beech Family, [22]
Beggar Lice, [94]
Beggar Ticks, [124]
Bellflower, [112]
Bellflower Family, [112]
Bellwort, [12]
Benzoin, [41]
Berberidaceae, [40]
Berberis, [40]
Bergamot Mint, [98]
Berula, [81]
Betula, [21], [22]
Betulaceae, [21]
Bidens, [123], [124]
Bilberry, [86], [87]
Bindweed, [91], [92]
Bindweed, Black, [28]
Birch, [21], [22]
Birch Family, [21]
Bird-foot Violet, [75]
Birthwort Family, [25]
Bishop's Cap, [51]
Bistort, [28]
Bitter Cress, [45], [47]
Bitter Dock, [26]
Bitter Nut, [21]
Bittersweet, [100]
Bitter-sweet, [69]
Black Alder, [69]
Black Ash, [88]
Blackberry, [53]
Black Bindweed, [28]
Black Cherry, [54]
Black Currant, [49], [50]
Black-eyed Susan, [128]
Black Haw, [111]
Black Jack Oak, [22]
Black Locust, [58]
Black Maple, [70]
Black Medick, [60]
Black Mustard, [44]
Black Oak, [23]
Black Raspberry, [53]
Black Snakeroot, [82]
Black Spruce, [1]
Black Swallow-wort, [90]
Black Walnut, [21]
Black Willow, [20]
Bladder Campion, [34]
Bladder Nut, [69]
Bladder Nut Family, [69]
Bladderwort, [106]
Bladderwort Family, [105]
Blazing Star, [13], [121]
Blephilia, [96]
Blite, [29]
Bloodroot, [41]
Bloody Dock, [26]
Blue Ash, [88]
Bluebell, [93], [94]
Blueberry, [86]
Blue Cohosh, [40]
Blue-eyed Grass, [15]
Blue-eyed Mary, [104]
Blue Flag, [15]
Blue Grass, [7]
Blue Hearts, [104]
Blue-joint, [5]
Bluets, [108]
Blue Violet, [76]
Blueweed, [94]
Boehmeria, [24]
Bog Rosemary, [86]
Boltonia, [131]
Boneset, False, [122]
Borage, [93]
Borage Family, [93]
Boraginaceae, [93]
Borago, [93]
Bowman's Root, [57]
Box Elder, [70]
Brasenia, [35]
Brassica, [43], [44]
Brauneria, [131]
Braya, [47]
Bristly Locust, [58]
Bristly Sarsaparilla, [80]
Brome-grass, [7]
Bromus, [7]
Broom-rape Family, [106]
Buchnera, [104]
Buckbean, [88]
Buckeye, [70]
Buckhorn, [107]
Buckthorn, [71]
Buckthorn Family, [71]
Buckwheat, [27]
Buckwheat, False, [28]
Buckwheat Family, [25]
Buffalo Berry, [77]
Buffalo Bur, [100]
Buffalo Clover, [61]
Bugbane, [39]
Bugle, [98]
Bugle Weed, [95]
Bug-seed, [28]
Bulrush, [7]
Bur Clover, [60]
Bur Cucumber, [112]
Burdock, [117]
Bur Marigold, [124]
Burnet, [57]
Bur Oak, [23]
Bur-reed, [2]
Bur-reed Family, [2]
Bush Clover, [61], [63]
Bush Honeysuckle, [110]
Butter-and-eggs, [102]
Buttercup, [36], [37], [38]
Butterfly Weed, [91]
Butternut, [21]
Butterwort, [105]
Button Bush, [108]
Cacalia, [122]
Cactaceae, [77]
Cactus Family, [77]
Cakile, [45]
Calamagrostis, [5]
Calamint, [97]
Calla, [9]
Callirhoe, [73]
Callitrichaceae, [68]
Callitriche, [68]
Calopogon, [16]
Caltha, [36]
Calypso, [17]
Camassia, [14]
Camelina, [42]
Camomile, [130]
Campanula, [112]
Campanulaceae, [112]
Campion, [33], [34]
Canada Thistle, [118]
Canada Violet, [76]
Canadian Blue Grass, [7]
Cancer-root, [106]
Cannabis, [24]
Caper Family, [47]
Capparidaceae, [47]
Caprifoliaceae, [109]
Capsella, [46]
Caraway, [83]
Cardamine, [45], [47]
Cardinal Flower, [113]
Carduus, [118]
Carex, [8]
Carpet-weed, [31]
Carpet-weed Family, [31]
Carpinus, [21]
Carrion-flower, [11]
Carrot, Wild, [82]
Carum, [83]
Carya, [21]
Caryophyllaceae, [31]
Cashew Family, [68]
Cassia, [60]
Castalia, [35]
Castanea, [22]
Castilleja, [102]
Catchfly, [33], [34]
Catnip, [98]
Cat-tail, [2]
Cat-tail Family, [2]
Caulophyllum, [40]
Ceanothus, [71]
Cedar, [1]
Celandine, [41]
Celandine Poppy, [41]
Celastraceae, [69]
Celastrus, [69]
Celtis, [24]
Cenchrus, [5]
Centaurea, [121]
Centaurium, [89]
Centaury, [89]
Cephalanthus, [108]
Cerastium, [33]
Ceratophyllaceae, [34]
Ceratophyllum, [34]
Cercis, [58]
Chaerophyllum, [83]
Chamaedaphne, [86]
Chamaelirium, [13]
Charlock, [44]
Cheat, [7]
Chelidonium, [41]
Chelone, [104]
Chenopodiaceae, [28]
Chenopodium, [28], [29]
Cherry, [54]
Cherry, Ground, [101]
Chervil, [83]
Chestnut, [22]
Chickweed, [32], [33]
Chickweed, Mouse-ear, [33]
Chicory, [115]
Chimaphila, [85]
Chiogenes, [85]
Chives, Wild, [13]
Chokeberry, [55]
Choke Cherry, [54]
Chrysanthemum, [121], [130], [131]
Chrysosplenium, [50]
Cichorium, [115]
Cicuta, [82]
Cimicifuga, [39]
Cinquefoil, [52], [56], [57]
Circaea, [78]
Cirsium, [117], [118]
Cistaceae, [74]
Cladium, [8]
Clammy Locust, [58]
Clammy-weed, [47]
Claytonia, [34]
Clearweed, [24]
Cleft Phlox, [92]
Clematis, [35]
Climbing Fumitory, [41]
Climbing Rose, [52]
Clintonia, [13]
Clover, [61]
Clover, Bush, [61], [63]
Clover, Hop, [60]
Clover, Prairie, [60]
Clover, Sweet, [61]
Cocklebur, [114]
Cockle, Corn, [33]
Coffee-tree, [58]
Cohosh, Blue, [40]
Colic-root, [13]
Collinsia, [104]
Collinsonia, [95]
Coltsfoot, [122], [130]
Columbine, [36]
Comandra, [24]
Comfrey, [93], [94]
Commelina, [9]
Commelinaceae, [9]
Common Blue Violet, [76]
Common Cat-tail, [2]
Common Vetch,
[59]
Compass Plant, [127]
Compositae, [113]
Composite Family, [113]
Coneflower, Gray-headed, [128]
Coneflower, Purple, [131]
Conioselinum, [83]
Conium, [83]
Conopholis, [106]
Conringia, [42]
Convolvulaceae, [91]
Convolvulus, [91], [92]
Coptis, [39]
Corallorhiza, [16]
Coral Root, [16]
Coreopsis, [123], [124]
Corispermum, [28]
Cork Elm, [24]
Cornaceae, [83]
Corn Cockle, [33]
Corn Flower, [121]
Corn Gromwell, [94]
Corn Salad, [111]
Cornus, [83], [84]
Corydalis, [42]
Corylus, [22]
Costmary, [121]
Cotton Grass, [8]
Cotton Thistle, [118]
Cottonwood, [19]
Cowbane, [81]
Cowherb, [34]
Cow Parsnip, [82]
Cowslip, [36]
Cow Wheat, [104]
Crab, [54]
Crab Grass, [5]
Crack Willow, [20]
Cranberry, [85]
Cranberry Tree, [111]
Crane-fly Orchis, [16]
Crane's-bill, [64], [65]
Crassulaceae, [48]
Creeping Cedar, [1]
Creeping Wahoo, [69]
Crepis, [117]
Cress, [43]-[47]
Cress, Bitter, [45], [47]
Cress, Field, [46]
Cress, Garden, [45], [46]
Cress, Lake, [45], [46]
Cress, Mouse-ear, [47]
Cress, Penny, [46]
Cress, Rock, [46], [47]
Cress, Water, [45]
Cress, Winter, [44]
Cress, Yellow, [43]
Crotalaria, [59]
Crowberry, [68]
Crowberry Family, [68]
Crowfoot, [35]
Crowfoot, Cursed, [37]
Crowfoot Family, [35]
Crowfoot, Sea-side, [36]
Crowfoot, Small-flowered, [36]
Crowfoot, Water, [35], [37]
Cruciferae, [42]
Cryptotaenia, [82]
Cuckoo Flower, [45]
Cucurbitaceae, [112]
Cudweed, [120], [121]
Culver's Root, [104]
Cup Plant, [123]
Currant, [49], [50]
Currant, Indian, [110]
Cursed Crowfoot, [37]
Cuscuta, [92]
Custard Apple Family, [40]
Cut-grass, [5]
Cycloloma, [29]
Cynanchum, [90]
Cynoglossum, [93], [94]
Cynthia, [115]
Cyperaceae, [7]
Cyperus, [8]
Cypress Spurge, [67]
Cypripedium, [18]
Dactylis, [6]
Daisy, Ox-eye, [131]
Dalibarda, [56]
Dame's Rocket, [47]
Dandelion, [115]
Dandelion, Dwarf, [115]
Datura, [100]
Daucus, [82]
Day-flower, [9]
Day Lily, [11]
Dead Nettle, [99]
Decodon, [77]
Deerberry, [86]
Dentaria, [44]
Deptford Pink, [34]
Desmodium, [62], [63]
Devil's Club, [80]
Dewberry, [53]
Dianthera, [107]
Dianthus, [34]
Dicentra, [41]
Diervilla, [110]
Digitaria, [5]
Dioscorea, [14]
Dioscoreaceae, [14]
Diplotaxis, [42], [43]
Dipsacaceae, [112]
Dipsacus, [112]
Dirca, [77]
Ditch Stonecrop, [49]
Dock, [26]
Dock, Prairie, [122]
Dodder, [92]
Dodecatheon, [87]
Dogbane, [90]
Dogbane Family, [90]
Dog Fennel, [130]
Dog Rose, [52]
Dog's-tooth Violet, [12]
Dog Violet, [76]
Dogwood, [83], [84]
Dogwood Family, [83]
Downy Mint, [78]
Draba, [42], [46]
Dracocephalum, [96]
Dragon Head, [96]
Dragon Head, False, [99]
Dragon Root, [8]
Drop-seed, [5]
Drosera, [48]
Droseraceae, [48]
Duckweed, [9]
Duckweed Family, [9]
Dulichium, [7]
Dutchman's Breeches, [41]
Dwarf Birch, [22]
Dwarf Dandelion, [115]
Dwarf Dogwood, [83]
Dwarf Ginseng, [80]
Dwarf Iris, [15]
Dwarf Mistletoe, [25]
Dwarf Raspberry, [53]
Dwarf Water Plantain, [3]
Dwarf White Trillium, [12]
Dyer's Greenweed, [58]
Echinochloa, [5]
Echinocystis, [112]
Echinodorus, [3]
Echinops, [117]
Echium, [94]
Eel Grass, [3]
Elaeagnaceae, [77]
Elatinaceae, [74]
Elatine, [74]
Elder, [109]
Elder, Box, [70]
Elder, Marsh, [114]
Elecampane, [127]
Eleocharis, [7]
Eleusine, [6]
Elm, [24]
Elodea, [3]
Elymus, [6]
Empetraceae, [68]
Empetrum, [68]
Enchanter's Nightshade, [78]
English Plantain, [107]
Epifagus, [106]
Epigaea, [85]
Epilobium, [79]
Epipactis, [17]
Eragrostis, [7]
Erechtites, [122]
Ericaceae, [84]
Erigenia, [81]
Erigeron, [130]-[132]
Eriocaulaceae, [9]
Eriocaulon, [9]
Eriophorum, [8]
Erodium, [64]
Eryngium, [80]
Erysimum, [43]
Erythronium, [12]
Eupatorium, [121], [122]
Euphorbia, [67], [68]
Euphrasia, [102]
Evening Primrose, [78]
Evening Primrose Family, [78]
Everlasting, [120]
Everlasting, Pearly, [120]
Evonymus, [69]
Eyebright, [102]
Fagaceae, [22]
Fagopyrum, [27]
Fagus, [22]
Fall Dandelion, [115]
False Asphodel, [14]
False Boneset, [122]
False Buckwheat, [28]
False Dragon Head, [99]
False Flax, [42]
False Foxglove, [102]
False Gromwell, [93]
False Heather, [74]
False Loosestrife, [78]
False Mermaid, [68]
False Mermaid Family, [68]
False Mitrewort, [51]
False Nettle, [24]
False Pimpernel, [104]
False Solomon's Seal, [14]
Fatsia, [80]
Fennel, [81]
Fennel, Dog, [130]
Fescue Grass, [7]
Festuca, [7]
Feverfew, [130]
Feverwort, [109]
Field Cress, [46]
Field Garlic, [13]
Figwort, [103]
Figwort Family, [101]
Filipendula, [57]
Fire Pink, [33]
Fireweed, [79], [122]
Five-finger, [55]
Flax, [63]
Flax, False, [42]
Flax Family, [63]
Fleabane, [131], [132]
Floating Foxtail, [4]
Floating Heart, [88]
Floerkea, [68]
Flowering Dogwood, [83]
Flowering Raspberry, [54]
Flowering Wintergreen, [65]
Flower-of-an-hour, [72]
Foeniculum, [81]
Fog Fruit, [99]
Forget-me-not, [94]
Forked Chickweed, [31]
Four-o'Clock Family, [31]
Foxglove, False, [102]
Fox Grape, [72]
Foxtail, [4]
Foxtail, Floating, [4]
Fragaria, [56]
Frasera, [88]
Fraxinus, [88]
Fringed Gentian, [89]
Fringed Orchis, [19]
Frog's Bit Family, [3]
Frost Grape, [72]
Frostweed, [74]
Fumaria, [42]
Fumariaceae, [41]
Fumitory, [42]
Fumitory, Climbing, [41]
Fumitory Family, [41]
Galeopsis, [99]
Gale, Sweet, [21]
Galinsoga, [130]
Galium, [108], [109]
Garden Cress, [45], [46]
Garden Phlox, [92]
Garlic, Field, [13]
Gaultheria, [86]
Gaura, [79]
Gaylussacia, [86]
Genista, [58]
Gentian, [89]
Gentiana, [89]
Gentianaceae, [88]
Gentian Family, [88]
Gentian, Spurred, [89]
Geraniaceae, [64]
Geranium, [64], [65]
Geranium Family, [64]
Gerardia, [102], [103]
Geum, [56], [57]
Giant Hyssop, [97]
Giant Ragweed, [114]
Gillenia, [57]
Ginseng, [80]
Gleditsia, [58]
Globe-flower, [36]
Globe Thistle, [117]
Glyceria, [7]
Gnaphalium, [120], [121]
Goat's Rue, [60]
Golden Alexander, [81]
Golden Currant, [49]
Golden Glow, [128]
Goldenrod, [125]-[127]
Golden Saxifrage, [50]
Golden Seal, [38]
Gold-thread, [39]
Good King Henry, [29]
Gooseberry, [49]
Goosefoot, [28], [29]
Goosefoot Family, [28]
Gourd Family, [112]
Gramineae, [4]
Grape, [72]
Grape Family, [71]
Grape Hyacinth, [14]
Grass Family, [4]
Grass of Parnassus, [50]
Grass, Star, [14]
Gratiola, [104]
Gray-headed Coneflower, [128]
Great Lobelia, [113]
Great Solomon's Seal, [11]
Great-spurred Violet, [75]
Greek Valerian, [92]
Green Ash, [88]
Green Brier, [11]
Green Foxtail, [4]
Green Milkweed, [90]
Green Sorrel, [25]
Green Violet, [75]
Grindelia, [128]
Ground Cherry, [101]
Ground Hemlock, [2]
Ground Ivy, [98]
Groundsel, [128]
Gum Plant, [128]
Gymnocladus, [58]
Gypsophila, [34]
Gypsophyll, [34]
Habenaria, [18], [19]
Hackberry, [24]
Hair Grass, [6]
Halenia, [89]
Haloragidaceae, [79]
Hamamelidaceae, [51]
Hamamelis, [51]
Hand-leaf Violet, [75]
Harbinger of Spring, [81]
Hardhack, [53]
Harebell, [112]
Hare's Ear, [42]
Hawksbeard, [117]
Hawkweed, [116], [117]
Hazel, [22]
Heather, False, [74]
Heath Family, [84]
Hedeoma, [95]
Hedge Hyssop, [104]
Hedge Mustard, [44]
Hedge Nettle, [99]
Helenium, [127], [128]
Helianthemum, [74]
Helianthus, [128]-[130]
Heliopsis, [123]
Hemerocallis, [11]
Hemlock, [1]
Hemlock, Ground, [2]
Hemlock Parsley, [83]
Hemlock, Poison, [83]
Hemlock, Water, [82]
Hemp, [24]
Hemp, Indian, [90]
Hemp Nettle, [99]
Hemp, Water, [30]
Hemp Weed, [131]
Henbane, [101]
Hepatica, [38]
Heracleum, [82]
Herb Robert, [64]
Herb Sophia, [43]
Hercules' Club, [80]
Hesperis, [47]
Heteranthera, [10]
Heuchera, [50], [51]
Hibiscus, [72]
Hickory, [21]
Hieracium, [116], [117]
Hill's Oak,