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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 |