24. SERICOCÁRPUS, Nees. WHITE-TOPPED ASTER. Heads 12--20-flowered, radiate; the rays about 5, fertile (white). Involucre somewhat cylindrical or club-shaped; the scales closely imbricated in several rows, cartilaginous and whitish, appressed, with short and abrupt often spreading green tips. Receptacle alveolate-toothed. Achenes short, inversely pyramidal, very silky; pappus simple, of numerous capillary bristles.--Perennial tufted herbs (1--2° high), with sessile somewhat 3-nerved leaves, and small heads mostly in little clusters, disposed in a flat corymb. Disk-flowers pale yellow. (Name from σηρικός, _silky_, and καρπός, _fruit_.) [*] _Pappus rusty; leaves sparingly serrate, veiny, rather thin._ 1. S. conyzoìdes, Nees. Somewhat pubescent; leaves oblong-lanceolate or the lower spatulate, ciliate; heads rather loosely corymbed, obconical (4--6´´ long).--Dry ground; Maine to Ohio, and southward. July. [*][*] _Pappus white; leaves entire, obscurely veined, firmer and smaller._ 2 S. solidagíneus, Nees. Smooth, slender; leaves linear, rigid, obtuse, with rough margins, tapering to the base; heads narrow (3´´ long), in close clusters, few-flowered.--Thickets, S. New Eng. to Tenn., and southward. July. 3. S. tortifòlius, Nees. Hoary-pubescent; leaves obovate or oblong-spatulate, short (½--1´ long), vertical, both sides alike; heads rather loosely corymbed, obovoid (4--5´´ long).--Pine woods, Va. and southward. Aug. 25. ÁSTER, L. STARWORT. ASTER. Heads many-flowered, radiate; the ray-flowers in a single series, fertile. Scales of the involucre more or less imbricated, usually with herbaceous or leaf-like tips. Receptacle flat, alveolate. Achenes more or less flattened; pappus simple, of capillary bristles (double in §§ 4 and 5).--Perennial herbs (annual only in §§ 7 and 8), with corymbed, panicled, or racemose heads; flowering in autumn. Rays white, purple, or blue; the disk yellow, often changing to purple. (Name ἀστήρ, _a star_, from the radiate heads of flowers.) Conspectus of Groups. Annuals, with copious fine soft pappus 53, 54 Pappus double 46--48 Scales closely imbricated, not green-tipped, often scarious-edged 49--52 Scales closely imbricated, scarcely at all herbaceous; leaves cordate, serrate 2, 3 Scales nearly equal, rigid, more or less foliaceous; pappus-bristles rigid, some thickened at top 1 Scales with herbaceous tips or the outer wholly foliaceous. ASTER proper. Pappus rigid; stem-leaves sessile, none cordate or clasping; heads few, large 4--8 Leaves silvery-silky both sides, sessile, entire 14, 15 Lower leaves more or less cordate, petiolate 17--24