Helminthotheca

Zinn

Cat. Pl. Hort. Gott., 430. 1757.

Common names: Oxtongue
Etymology: Greek helminthos, worm, and Latin theca, case or container allusion unclear, perhaps to shapes of cypselae
Treatment appears in FNA Volume 19. Treatment on page 300. Mentioned on page 216.
Revision as of 20:17, 16 December 2019 by FNA>Volume Importer

Annuals or biennials, 10–100+ cm; taprooted. Stems usually 1, erect, branched distally or throughout, hirsute to hispid or setose (hair tips 2–4-hooked). Leaves basal and cauline; basal ± petiolate, distal sessile; blades elliptic, lanceolate, oblanceolate, oblong, or ovate, margins usually dentate to pinnately lobed (faces hirsute to hispid, hair tips 2–4-hooked). Heads borne singly or in loose, corymbiform arrays. Peduncles (terminal and axillary) not inflated distally, seldom bracteate. Calyculi of (3–)5, cordate or ovate to lance-ovate, foliaceous bracts. Involucres ovoid to urceolate, 9–12+ mm diam. (larger in fruit). Phyllaries (5–)8–13+ in 1 series, lance-linear to linear, subequal, margins little, if at all, scarious, apices acuminate. Receptacles flat, pitted, glabrous, epaleate. Florets 30–60+; corollas yellow (often reddish abaxially). Cypselae (dimorphic): outer whitish, bodies gibbous, ribs 5–10, beaks about equaling bodies, fragile, faces hirtellous to pilosulous adaxially; inner reddish brown, bodies ± compressed-ellipsoid to fusiform, beaks about equaling or longer than bodies, fragile, faces transversely rugulose to muricate, otherwise glabrous; pappi persistent, of 10–15+, whitish, subequal, barbellate or plumose, subulate to setiform (basally connate) scales in 1–2 series. x = 5.

Distribution

Europe, widely introduced.

Discussion

Species 4 (1 in the flora).