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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 |