Heads discoid, cylindric or nearly so, white or flesh- colored, not yellow; invol a single series of herbaceous or subherbaceous bracts, often with scarious margins, sometimes also with some reduced basal bracteoles; receptacle naked, flat, or sometimes with a conic central projection; fls all perfect, the cor deeply 5-lobed; style- branches flattened, truncate or with a very short appendage, penicillate, the ventromarginal stigmatic lines expanded and confluent on the inner surface; achenes cylindric, several-nerved; pappus of numerous capillary bristles; perennial herbs with alternate, petiolate lvs and medium- sized heads, sometimes with ±milky juice. (Mesadenia, Synosma) 50, N. Amer., 1 Eurasia.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.