52. Brickellia Elliott
Plants
perennial, often with thickened roots. Stems solitary to several, erect or
ascending, usually sparsely to densely pubescent with short, curly or curved
hairs. Leaves alternate or opposite (the nodes usually well separated), sessile
to long-petiolate, the basal leaves usually absent at flowering, when present
then about as large as or smaller than the lower and median stem leaves. Leaf
blades linear to ovate-triangular or nearly heart-shaped, tapered, angled,
truncate, or cordate at the base, usually tapered to a sharply pointed tip, the
surfaces variously short-hairy to glabrous or nearly so, at least the
undersurface also glandular, with (1)3(5) main veins. Inflorescences panicles,
sometimes reduced to stalked clusters at the branch tips, flat-topped to
dome-shaped, or less commonly appearing as a leafy panicle with racemose
branches. Heads with 6–40 disc florets. Involucre narrowly cup-shaped to
narrowly bell-shaped, the bracts 22–35 (the head often also subtended by 1 or
more other shorter bracts) in usually several unequal, overlapping series, the
bracts linear to narrowly oblong-elliptic or narrowly oblanceolate, those of
the outer series sometimes ovate, tapered or narrowed to a bluntly or sharply
pointed tip, glabrous or sparsely to moderately and finely short-hairy, also
glandular. Receptacle flat or nearly so. Corollas cream-colored to greenish
yellow. Pappus of 20–25 bristles, these minutely barbed or plumose. Fruits 1.7–5.0
mm long, (8–)10-nerved or ribbed, slightly wedge-shaped in profile (usually
slightly and unevenly tapered at the base) to nearly linear, usually minutely
hairy, brown to dark brown. About 100 species, North America, Central America,
South America, most diverse in the U.S. and Mexico.