Youngia

Annuals, biennials [perennials], (10-)20-90+ cm; taprooted. Stems 1-5+, erect (often scapiform), usually branched distally, sometimes throughout, proximally glabrous, puberulent, or tomentose. Leaves all or mostly basal; petiolate (petiole bases often dilated, ± clasping); blades oblong or ovate to oblanceolate, margins usually pinnately lobed (± lyrate), ultimate margins denticulate. Heads (4-150) in corymbiform to paniculiform arrays. Peduncles (filiform) not distally inflated, seldom bracteate. Calyculi of 3-5+, deltate to ovate (membranous) bractlets. Involucres cylindric to campanulate, 2-3+ mm diam. Phyllaries usually 8 in 1-2 series, lanceolate to linear, ± equal (reflexed in fruit), margins ± scarious, apices obtuse to acute. Receptacles flat to convex, ± pitted, glabrous, epaleate. Florets 8-25+; corollas yellow, sometimes abaxially purplish (anther bases with linear, acute auricles). Cypselae ± reddish brown, ± fusiform and compressed [± terete], weakly or not beaked, ribs 11-13, ± spiculate to scabrellous on ribs; pappi (borne on discs at tips of cypselae) persistent (fragile) [falling], of 40-60+, basally coherent [distinct], white [yellowish or grayish], subequal, smooth to barbellulate bristles in ± 1 series. . = 5 or 8.

Youngia americana Babcock (based on a specimen from Alaska) has not been used as an accepted name for plants in the flora area; it was treated as a synonym of Crepis nana var. lyratifolia (Turczaninow) Hultén by E. Hultén (1968).

Fls all ligulate and perfect, yellow; invol calyculate at base; achenes slightly compressed, fusiform, tapering above but scarcely beaked, slightly expanded to the pappiferous disk at the summit, strongly and somewhat unequally 11-13-ribbed; pappus of numerous fine white capillary bristles; herbs with milky juice and alternate, often mainly basal lvs. 35, Asia.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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