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1 Stem leaves sessile; pappus of the pistillate ( ray) flowers consisting only of a few short, slender scales, < 1 mm long (visible at 20× magnification); annual or perennial (rarely biennial); [section Phalacroloma]. |
2 Stem leaves many, mostly toothed, the larger > 1 cm wide; pubescence of the mid-stem long and spreading, of dense, flattened hairs; plants to 15 dm tall. |
2 Stem leaves few, mostly entire, the larger usually < 1 cm wide; pubescence of the mid-stem usually short and appressed, of flattened hairs, mainly restricted to the lower stem (or entirely absent); plants to 8 dm tall. |
3 Plants perennial, rhizomatous; [plants of shallow soil over calcareous rock]. |
4 Basal leaves oblanceolate to narrowly obovate or spatulate, (3.2-) 3.8-15 (-21) mm wide; cauline leaves glabrous, except along the midvein and the ciliate margins; [of limestone glades and barrens of c. TN, nw. GA, and n. AL] |
4 Basal leaves linear- oblanceolate, 1-3.5 (-6) mm wide; cauline leaves sparsely to moderately strigillose; [of dolostone glades of c. AL (Bibb Co.)] |
3 Plants annual (rarely biennial), lacking rhizomes; [of various, often weedy, habitats] |
5 Plants lacking flattened trichomes throughout (absent on the stems and the phyllaries]; plants sexual, diploid, with well-formed pollen grains < 15 µm in diameter; [of w. LA and e. TX] |
5 Plants often with flattened trichomes on the stems; plants asexual, apomictic, with very variable, poorly formed pollen grains, some > 17 µm in diameter; [widespread] |
6 Phyllary hairs flattened, 0.5-1.2 mm long; stem hairs appressed to spreading, 0.5-1.0 mm long |
6 Phyllary hairs terete, mostly 0.1-0.5 mm long; stem hairs appressed to spreading, 0.1-0.4 (-0.8) mm long |
1 Stem leaves relatively large and clasping, or small and sessile (in E. vernus); pappus of the pistillate ( ray) flowers of elongate capillary bristles (sometimes also with scales); plants biennial or perennial. |
7 Plants trailing or ascending, rooting at the nodes, and with stolons; [section Cincinnactis] |
7 Plants erect (sometimes the shoots curved at the base but ultimately vertical). |
8 Stem leaves not clasping; basal leaves fleshy; rays 25-40, white, 0.5-1.3 mm wide; [of moist to wet habitats of the Coastal Plain]; [section Erigeridium] |
8 Stem leaves clasping; basal leaves herbaceous; rays 50-400, pink, blue, purplish, or white, either 0.3-0.5 mm wide (in E. philadelphicus var. philadelphicus, E. quercifolius, and E. tenuis) or 0.8-1.2 mm wide (in E. pulchellus var. pulchellus); [of more general distribution and habitat]. |
9 Disk corollas 4-6 mm long; rays 50-100, 0.8-1.2 mm wide; plants clonal by rhizomes and stolons; [section Pauciflori]. |
10 Stems and leaves glabrous |
10 Stems and leaves densely pubescent with long hairs |
9 Disk corollas 2.0-3.2 mm long; rays 60-400, 0.3-0.5 mm wide; plants solitary from a caudex. |
11 Involucre 4-6 mm high; rays 150-400, white to deep pink, 5-10 mm long; [section Quercifolium] |
11 Involucre 2.5-4 mm high; rays 60-250, blue-lavender (rarely white to pink), 2.5-5 (-6) mm long. |
12 Pappus simple; stem spreading pubescent throughout (or appressed pubescent in the upper third only); rays 100-250; [section Quercifolium] |
12 Pappus double, with short outer setae in addition to the long slender bristles; stem appressed pubescent in at least the upper half; rays 60-120; [section Phalacroloma] |