Part 17

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.