Var. gigantèa, Gray. Commonly tall, 5–8° high; leaves more or less pubescent or hispidulous beneath. (S. gigantea, Ait.; S. serotina of previous ed.)—Thickets and low grounds, Can. to Tex.
32. S. rupéstris, Raf. Stem smooth, slender, 2–3° high; leaves linear-lanceolate, tapering both ways, entire or nearly so; panicle narrow; heads very small; rays 4–6, very short.—Rocky river-banks, W. Va. to Ky. and Ind.
[=][=] Pubescent (at least the stem) or hispidulous-scabrous.
33. S. Canadénsis, L. Stem rough-hairy, tall and stout (3–6° high); leaves lanceolate, pointed, sharply serrate (sometimes almost entire), more or less pubescent beneath and rough above; heads small; rays very short.—Borders of thickets and fields; very common.—Varies greatly in the roughness and hairiness of the stem and leaves, the latter oblong-lanceolate or elongated linear-lanceolate;—in var. pròcera, whitish-woolly underneath; and in var. scàbra also very rough above, often entire, and rugose-veined.
34. S. nemoràlis, Ait. Clothed with a minute and close grayish-hoary (soft or roughish) pubescence; stem simple or corymbed at the summit (½–2½° high); leaves oblanceolate or spatulate-oblong, the lower somewhat crenate-toothed and tapering into a petiole; racemes numerous, dense, at length recurved, forming a large and crowded compound raceme or panicle which is usually turned to one side; scales of the involucre linear-oblong, appressed; rays 5–9.—Dry sterile fields; very common. Flowers very bright yellow, beginning early in Aug.—Var. incàna, Gray, of Minn., and westward, is a dwarf form, with rigid oval or oblong leaves, rather strongly serrate or entire, and the clusters of heads in a dense oblong or conical thyrse.
35. S. rádula, Nutt. Stem and oblong or obovate-spatulate leaves rigid and very rough, not hoary, the upper sessile; scales oblong, rigid; rays 3–6; otherwise nearly as in n. 34.—Dry hills, W. Ill., Minn. Kan., and southward.
36. S. Drummóndii, Torr. & Gray. Stem (1–3° high) and lower surface of the broadly ovate or oval somewhat triple-ribbed leaves minutely velvety-pubescent, some of the leaves almost entire; racemes panicled, short; scales of the involucre oblong, obtuse; rays 4 or 5.—S. W. Ill., Mo., and southward.
[+][+][+][+] Heads in a compound corymb terminating the simple stem, not at all racemose; leaves mostly with a strong midrib.
[++] Leaves flat, not 3-nerved.
37. S. rígida, L. Rough and somewhat hoary with a minute pubescence; stem stout (2–5° high), very leafy; corymb dense; leaves oval or oblong, copiously feather-veined, thick and rigid; the upper closely sessile by a broad base, slightly serrate, the uppermost entire; heads large, over 30-flowered; the rays 7–10.—Dry soil, N. Eng. to Minn., and southward.