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1 Pappus present, of 5-60 barbellate bristles; receptacle naked (without paleae or well-developed bristles); [tribe Heliantheae; subtribe Eupatoriae]. |
..2 Plant a twining herb, phyllaries and disk florets 4 per head |
..2 Plant stiffly erect to sprawling but never twining, phyllaries and disk florets usually > 4 per head. |
....3 Leaves in whorls of 3-7, > 2 cm wide |
....3 Leaves opposite, rarely alternate or whorled, if whorled, < 2 cm wide. |
......4 Cypselae rostrate (with long beaks); the achene portion not bearing ribs |
......4 Cypselae not beaked, the achene variously ribbed. |
........5 Achenes (and ovaries) 8-10-ribbed; outer phyllaries longitudinally striate |
........5 Achenes (and ovaries) (3-) 4-5-ribbed; outer phyllaries not noticeably longitudinally striate. |
..........6 Heads pink to blue. |
............ 7 Phyllaries in 4-6+ series, deciduous |
............ 7 Phyllaries in 2-4 series, persistent (or deciduous in Praxelis). |
............ ..8 Heads pink (rarely bluish); receptacles flat; florets 18-25 per head; leaves sometimes gland-dotted |
............ ..8 Heads blue; receptacles conic; florets 25-70 per head; leaves gland-dotted. |
............ ....9 Bristles ca. 30; florets 35-70+; phyllaries ca. 25, subequal, persistent |
............ ....9 Bristles ca. 40; florets 25-30; phyllaries 15-25, unequal, deciduous (absence apparent in fruit) |
..........6 Heads white to cream or, rarely, pale lilac. |
............ ......10 Florets 3-7 per head |
............ ......10 Florets at least 9 per head. |
............ ........11 Phyllaries not strongly imbricate, with the principal ones subequal and sub-biseriate; petioles 0.5-10 cm |
............ ........11 Phyllaries clearly imbricate, in 3+ series, the margins usually glandular; some species epetiolate |
1 Pappus either absent, or of scales, setae, or awns; receptacle naked, paleate, or bearing bristles. |
............ ..........12 Leaves whorled, linear, < 2 mm wide; head solitary; [aquatic herb growing in shallow stagnant water] |
............ ..........12 Leaves opposite (or alternate in part), broader in shape and > 5 mm wide; heads typically not solitary; [terrestrial or wetland plants]. |
............ ............ 13 Receptacle naked (epaleate). |
............ ............ ..14 Pappus of 2-12 scales; heads white, pink, or blue (yellow in Schkuhria). |
............ ............ ....15 Heads with 20-125 florets; leaves serrate or ± dentate (at least distally); [rarely naturalized exotics or s. TX/FL natives]; [tribe Eupatorieae]. |
............ ............ ......16 Leaves petiolate; corolla tube glabrous, typically blue or lavender colored (sometimes white tinged); heads with 20-125 florets; [naturalized exotics or s. FL native] |
............ ............ ......16 Leaves sessile; corolla tube glandular-pubescent, typically white colored (sometimes pink-purple tinged); heads with 75-125 florets; [s. TX native] |
............ ............ ....15 Heads with 10-30 florets (or fewer in Schkuhria); leaves entire; [natives, of FL, s. GA, MS, and TX in our area]; [tribe Heliantheae; subtribe Chaenactidinae]. |
............ ............ ........17 Leaves 3-5 lobed (or foliolate); cypselae with curled hairs ( Florestina tripteris) or villous on angles ( Schkuhria pinnata); [s. TX in our area or ne. waif]. |
............ ............ ..........18 Heads discoid, corolla white; cypselae with curled hairs; [s. TX in our area] |
............ ............ ..........18 Heads discoid, sometimes with 1 (-2) diminuitive rays, corolla (of discs) yellow; cypselae villous, at least at bases or on angles; [waif of ne US, native in sw. US] |
............ ............ ........17 Leaves simple or unlobed; cypselae with straight hairs; [variously distributed in s. GA and FL w. to MO and s. TX] |
............ ............ ..14 Pappus none, or of a few bristles or irregular coroniform lobes; heads green to yellow. |
............ ............ ............ 19 Heads bright yellow, closely aggregated into corymbiform arrays of flat-topped to dome-shaped glomerules |
............ ............ ............ 19 Heads greenish or greenish yellow, borne in spiciform, racemiform, or paniculiform arrays. |
............ ............ ............ ..20 Heads in paniculiform arrays, all or most of the heads not subtended by bracts |
............ ............ ............ ..20 Heads in spiciform or racemiform arrays, each 1 (-2) heads subtended by a bract |
............ ............ 13 Receptacle with paleae or well-developed bristles. |
............ ............ ............ ....21 Heads small, less than 1 cm in diameter at anthesis (the female heads enlarging in Xanthium); disc florets dull white or suffused with green or purple; florets mainly unisexual (either in the same heads and then males central and females peripheral, or in separate female and male heads); female florets 0-8 per head; [tribe Heliantheae; subtribe Ambrosiinae] |
............ ............ ............ ......22 Heads unisexual; cypselas shed within an indurated bur or “nut” with hooked or straight spines developed from the phyllaries and/or paleae. |
............ ............ ............ ........23 Involucre of the female heads with tubercles or straight spines developing from the phyllaries; burs 1-8 mm long |
............ ............ ............ ........23 Involucre of the female heads with hooked spines developing from the phyllaries/paleae; burs 10-35 mm long |
............ ............ ............ ......22 Heads bisexual, with functionally male and female flowers in the same head; cypselas shed individually, not enclosed. |
............ ............ ............ ..........24 Heads in paniculiform arrays, all or most of the heads not subtended by bracts |
............ ............ ............ ..........24 Heads in spiciform or racemiform arrays, each 1 (-2) heads subtended by a bract |
............ ............ ............ ....21 Heads larger, mostly > 1 cm in diameter at anthesis; disc florets conspicuously white, yellow, pale yellow, or purple; florets mainly bisexual; female florets > 12 per head (except 2-8 in Polymnia and 8-15 in Verbesina occidentalis). |
............ ............ ............ ............ 25 Leaves strongly basally disposed, the basal-most leaves sitting almost flat on the ground and overlapping; disc flowers maroon-purple |
............ ............ ............ ............ 25 Leaves mainly or strictly cauline (not basally disposed); disc flowers white, yellow, or reddish-brown. |
............ ............ ............ ............ ..26 Disc flowers bright yellow or reddish-brown. |
............ ............ ............ ............ ....27 Involucre of phyllaries subtended by a calyculus of bracts obviously different in color, texture, and shape than the phyllaries. |
............ ............ ............ ............ ......28 Phyllaries usually distinct, rarely connate proximally; disk florets bright yellow |
............ ............ ............ ............ ......28 Phyllaries connate (both proximally-distally connate); disk florets yellow to reddish-brown |
............ ............ ............ ............ ....27 Involucre of phyllaries not subtended by a calyculus (phyllaries sometimes in 2+ series, but without obvious calyculi below). |
............ ............ ............ ............ ........29 Plants erect; heads without ray florets; [wet pine savannas and bogs; FL panhandle] |
............ ............ ............ ............ ........29 Plants primarily prostrate or trailing, sometimes erect; heads with or without ray florets; [habitats various, widespread natives and non-natives] |
............ ............ ............ ............ ..26 Disc flowers bright white or pale yellow. |
............ ............ ............ ............ ..........30 Stems not winged; plants erect or spreading. |
............ ............ ............ ............ ............ 31 Cypselae 3-4 angled; pappus falling (of 2-12 awns or bristles); leaf margins irregularly crenate to serrate, the surfaces sometimes roughened but lacking glands; [e. of TX] |
............ ............ ............ ............ ............ 31 Cypselae 5-ribbed; pappus absent; leaf margins entire or serrulate, the surfaces gland-dotted; [s. TX] |
............ ............ ............ ............ ..........30 Stems winged; plants erect. |
............ ............ ............ ............ ............ ..32 Disc flowers bright white; leaves unlobed or with 2 basal lobes |
............ ............ ............ ............ ............ ..32 Disc flowers creamy or pale yellow; leaves prominently pinnately lobed, with 5-many lobes |
1 Receptacle paleate (bearing receptacular bracts which individually subtend at least some of the flowers of the head). |
..2 Involucres absent or vestigial, usually with 0 phyllaries; heads very small, < 6 mm high, < 4 mm wide; annuals, < 4 dm tall; disc corollas hidden or dingy in color; [tribe Gnaphalieae] |
....3 Bisexual flowers (1-) 2-10 (-11), pappus of (11-) 13-28+ bristles visible in heads; functionally staminate flowers 0. |
......4 Receptacles cylindric to clavate (5-15× as tall as the diameter); most pistillate paleae open to ± folded (at most each enfolding, not enclosing a floret; apices acuminate to aristate); innermost paleae erect to ascending in fruit; cypselae mono- morphic (the outer ± equaling the inner) |
......4 Receptacles fungiform to obovoid (0.4-1.6× as tall as the diameter); most pistillate paleae ± saccate, each ± enclosing a floret, apices blunt; innermost paleae spreading in fruit; cypselae dimorphic (the outer longer than the inner) |
....3 Bisexual flowers 0 or 2-7, pappi 0; functionally staminate flowers 0 or 2-5, pappi 0 or of 1-10 (-13) bristles hidden in heads |
........5 Paleae of the bisexual or staminate flowers flat to concave, not enclosing florets, apices entire; cypselae glabrous; [mainly west of the Mississippi River, rarely east (as in MS, AL, GA, and SC] |
........5 Paleae of the bisexual flowers saccate, each enclosing a floret, apices 2-fid or 3-fid; cypselae (at least the outer) strigose; [se. Texas] |
..2 Involucres present, conspicuous, of many phyllaries; heads larger, 2-20+ mm wide; perennials or coarse annuals, 2-25 dm tall; disc corollas apparent, yellow, white, or pink to purplish. |
..........6 Disc flowers yellow or greenish yellow; [either native of s. TX southwards, or a waif] |
............ 7 Phyllary margins and tips scarious; fresh foliage aromatic |
............ 7 Phyllary margins and tips herbaceous; fresh foliage not aromatic |
..........6 Disc flowers white or whitish to pink or purple; [collectively widespread]. |
............ ..8 Heads in corymbiform arrays; heads bisexual; involucres not burlike or nutlike, lacking tubercles or hooked or straight prickles or spines; leaves lanceolate, unlobed, cuneate at base |
............ ....9 Heads lacking ray flowers; disc flowers pink (rarely nearly white); [Coastal Plain; FL and GA] |
............ ....9 Heads with 5 white (fading to cream), scoop-shaped, inconspicuous ray flowers (keyed here as a 'failsafe'); disc flowers white; [widespread in our region] |
............ ..8 Heads in spiciform or racemiform arrays; heads unisexual (each head either with only female or only male flowers); involucres burlike, with tubercles or straight or hooked spines or prickles; leaves ovate or broader (in outline), often pinnatifid or bipinnatifid, truncate, cordate, or cuneate at base; [collectively widespread in our region]. |
............ ......10 Involucres of pistillate heads (burs) 1-4 mm long, with (1-) 5-12+ straight spines; larger leaves bipinnatifid |
............ ......10 Involucres of pistillate heads (burs) 10-40 mm long, with 30-75+ hooked prickles; phyllaries larger leaves pinnatifid or unlobed |
1 Receptacle epaleate (lacking receptacular bracts individually subtending flowers, but the receptacle sometimes bearing bristles, setae, hairs, or pits with laciniate margins. |
............ ........11 Flowers white, pink, purple, or bluish. |
............ ..........12 Annuals, (1-) 2-10 (-30+) cm tall; corollas whitish, inconspicuous, absent on most of the (pistillate) flowers; leaves 2-3× pinnati-palmately lobed into linear segments; cypselae with an apical spine |
............ ..........12 Perennials, 10-150 cm tall; corollas at least light pink and often darker pink, purple, or blue, conspicuous, present on all flowers; leaves pinnately lobed or entire, the segments not linear; cypselae not spined. |
............ ............ 13 Heads ovoid, 10-21 mm long; flowers 15-40 mm long, with long, narrow lobes; phyllaries >30, in 6+ series, and the apices often with a fringe of appendages and/or a spine tip; basal and lower stem leaves usually pinnately lobed (to entire and unlobed); [widespread in our region, especially northwards] |
............ ............ 13 Heads cylindrical, 2-6 mm long; flowers ca. 3 mm long, with deltate lobes; phyllaries 12-15 in 2-3 series, herbaceous and unadorned; basal and lower stem leaves entire and unlobed; [Coastal Plain of FL and GA] |
............ ........11 Flowers yellow, cream, or rarely red-tinged. |
............ ............ ..14 Leaf blades unlobed. |
............ ............ ....15 Heads 3-4 (-6) mm in diameter, solitary; plants 0.3-3 dm tall; [ballast waif, especially in wet, saline places] |
............ ............ ....15 Heads (3-) 5-20+ mm in diameter, solitary or borne in corymbiform or paniculiform arrays; plants 1.5-15 dm tall. |
............ ............ ......16 Involucres 8-20+ mm in diameter; cypselae 1.5-4.5 mm long |
............ ............ ......16 Involucres (3-) 5-8 (-10) mm in diameter; cypselae 1.5-2 mm long |
............ ............ ..14 Leaf blades 1-3× pinnately or palmately lobed into linear or spatulate segments. |
............ ............ ........17 Annual 0.1-5 dm tall. |
............ ............ ..........18 Disc corollas cream to pale yellow, 0.5-0.8 mm long; fresh plants malodorous; [waif] |
............ ............ ..........18 Disc corollas greenish yellow, 1.1-1.3 mm long; fresh plants pineapple-scented; [common weed, especially northwards in our region] |
............ ............ ........17 Perennial, biennial or annual 4-15 dm tall. |
............ ............ ............ 19 Heads borne in paniculiform, racemiform, or spiciform arrays, never flat-topped; flowers < 50 per head |
............ ............ ............ 19 Heads borne in corymbiform arrays; flowers 60-300+ per head |