399. Trichocoronis A. Gray, Mem. Amer. Acad. Arts., n. s. 4: 65. 1849.
[Greek trichos, hair, and koronos, crown, apparently alluding to setiform pappus elements]
Guy L. Nesom
Annuals or perennials, 10–30 cm (aquatic or subaquatic). Stems decumbent to erect, branched from bases or ± throughout (sometimes rooting at proximal nodes). Leaves cauline; mostly opposite (distal sometimes alternate); sessile; blades usually 1–3-nerved from near bases, oblong to elliptic or lanceolate, margins usually ± dentate (at least distally), faces glabrous or sparsely pilose to pilosulous and glabrescent, sometimes minutely gland-dotted. Heads discoid, borne singly or in loose or open, corymbiform arrays. Involucres mostly hemispheric or broader, 3–4(–5) mm diam. Phyllaries persistent, 18–30 in 2–3 series, obscurely 3–4-nerved, lanceolate, ± equal (herbaceous). Receptacles convex to conic, epaleate (warty). Florets 75–125; corollas whitish or pinkish to purplish, throats tubular-funnelform (lengths ca. 2 times diams.); styles: bases not enlarged, glabrous, branches linear-filiform (distally densely papillose). Cypselae weakly fusiform, 4–5-ribbed, scabrellous on ribs; pappi persistent, of 2–6+ laciniate or fimbriate to setiform scales or coarsely barbellate bristles. x = 15.
Species 2 (1 in the flora): Texas, Mexico; introduced in California.
King, R. M. and H. Robinson. 1970b. A monograph of the genus Trichocoronis. Phytologia 19: 497–500.