(4-10 dm. high, usually unbranched)
=Lobelia, Lobelia spicata.=
5a. Foliage pubescent (3-8 dm. high)
=Indian Tobacco, Lobelia inflata.=
5b. Foliage glabrous (1-4 dm. high) =Lobelia, Lobelia kalmii.=
COMPOSITAE, the Composite Family
Herbs, with various types of foliage, but with flowers of characteristic
structure, resembling a sunflower, a thistle, or a dandelion. Each
apparent flower is a head of numerous small flowers, attached side by
side to the expanded end of the stem, and subtended and partly enclosed
by a series of bracts, called the involucre, which resembles a calyx.
The calyx of the individual flower is minute or actually wanting, and is
usually modified to aid in seed dispersal. It appears at the base of the
corolla, at the summit of the inferior ovary, and is known as pappus.
The structure of the pappus is best observed in the ripe fruit.
The corolla of the individual flowers consists of 5 (or rarely 4) united
petals. In some flowers the petals are united to form a tubular or
bell-shape corolla. In others they are united to form a flat or
strap-shape corolla. The stamens are attached to the corolla, and are
united by their anthers into a tube which surrounds the style, and above
which the 2-lobed stigma protrudes.
The apparent flower of a Composite, composed of several or many
individual flowers, is termed a head. It may be composed entirely of
tubular flowers, as the thistle or bone-set; or entirely of strap-shape
flowers, as the dandelion; or of both sorts together, as the aster or
sunflower. In the latter case, the tubular flowers invariably occupy the
center of the head, called the disk, and the larger strap-shape flowers
are at the margin, where their projecting corollas, called rays, may be
very conspicuous. Such heads are called radiate.
In a few composites (see 1a below) the flowers have minute corollas
without colored parts.
In identifying a composite, determine first whether the heads are
composed of tubular flowers, of strap-shape flowers, or of both sorts
together; and, secondly, observe the nature of the pappus, using
preferably the ripe heads, or at least the oldest flower-heads
available. No further difficulties will be encountered.
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.=