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3 Leaves lanceolate or broader, 1-5× as long as wide; receptacle paleate; [collectively widespread]. | |
4 Leaves lanceolate to oblanceolate, unlobed or obscurely 3-lobed; leaf blade margins toothed or entire; leaves strictly opposite; [tribe Heliantheae; subtribe Ecliptinae]. | |
6 Leaves lanceolate, sometimes 3-lobed, usually serrate but sometimes nearly entire; heads 4-8 mm in diameter; cypselas flattened and winged; [TX only] | |
7 Disc flowers pink, purple, or white. | |
8 Heads small (involucres 2-8 mm high), solitary, axillary in the axils of leaves or leafy bracts (similar to the leaves but smaller) or interpretable as arrayed in bracteate racemes; heads nodding, the involucre 2-7 mm high; [collectively widespread in coastal portions of our area, of maritime situations]; [tribe Heliantheae; subtribe Ambrosiinae] | |
8 Heads small to larger (involucres 3-15+ mm high), many, terminal on the branches of corymbiform or paniculiform arrays; heads erect, the involucre 4-12 mm high; [of Coastal Plain of FL, s. GA, and TX]. | |
10 Leaf blades triangular or lanceolate, truncate, cordate, or cuneate at the base, acute to acuminate at the apex; leaf margins serrate; leaves opposite throughout. | |
11 Phyllaries broad, 2-3× as long as wide, the inner phyllaries translucent-scarious white to pinkish at their broadly rounded apices, falling as the head goes to fruit | |
11 Phyllaries narrow, 4-7× as long as wide, the inner phyllaries green at their acute to acuminate apices, persistent on the head in age. | |
12 Involucres 2-3 mm in diameter; phyllaries 7-16 in 1-2 series; disc flowers 3-13 per head; [s. FL only (in our region)] | |
12 Involucres 3-7 mm in diameter; phyllaries 25-35 in 2-3 series; disc flowers 10-60 per head; [TX only (in our region)]. | |
17 Rays white, 21-34+; leaves obovate to oblanceolate, averaging ca. 4× as long as wide, dentate; [non-native, known in our region only from NY] | |
18 Heads pseudoradiate, with 11-25 pseudoray flowers and 0 disc flowers; leaves 8-70 mm wide | |
19 Phyllaries in 1-2 series and equal or subequal in length to one another, the phyllaries often coherent/fused (the involucre thus appearing as a cylinder with ribs extending from base to top; calyculus (of bracts subtending the phyllaries and differing from them in texture, color, or orientation) present; [tribe Senecioneae] | |
19 Phyllaries in 3-17 series and unequal in length (imbricated); calyculus absent. | |
20 Rays bright yellow, (0-) 1-9; involucre 1-2.5 (-3) mm in diameter. | |
21 Pappus of 40-60 barbellate bristles; ray blades 4-6 mm long; leaf surfaces minutely pebbled; intricately branched shrubs to 1 m tall, with persistent sterile shoots with evergreen leaves and annual flowering shoots (the entire shoot and leaves deciduous); [Coastal Plain, se. NC south to Panhandle FL and s. MS] | |
24 Leaves 1-pinnately lobed, the many (>21) lobes mostly < 1.5 mm long and wide | |
25 Plants dioecious, either male or female; heads either staminate, with 10-50 flowers, or pistillate, with 20-150 flowers | |
27 Leaves lanceolate to ovate (broadest below the midpoint); leaf margins entire to coarsely toothed. | |
28 Heads in leafy, paniculate arrays; leaf blades coarsely dentate, 0.5-4 cm long; shrubs to 12 dm tall; [c. and e. TX] | |
28 Heads borne in leafless, corymbiform arrays; leaf blades entire to denticulate, 5-16 (-20) cm long; shrubs to 40 dm tall; [FL and s. TX] | |
29 Leaf blades elliptic, acute to acuminate at the apex; leaf blade strongly bicolored above and below, the upper surface dark green and glabrate, the lower surface densely and finely tomentose and strongly whitened, the upper surface dark green and glabrate or glabrous; disc flowers 4-25 per head; [s. TX] |
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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] | |
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 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 | |
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. | |
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] | |
14 Leaf blades unlobed. | |
15 Heads (3-) 5-20+ mm in diameter, solitary or borne in corymbiform or paniculiform arrays; plants 1.5-15 dm tall. | |
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 | |