This is strictly an Old World family. All of our species are European natives, escaped from cultivation or otherwise naturalized. The flowers are in a dense involucrate head, but can be distinguished readily from those of the Asteraceae by the 4 corolla lobes and 4 conspicuous, separate stamens. The achenes in our species are hairy (glabrate in Succisella inflexa).

1. Involucral bracts with a prolonged spine at the tip, more than 4 times as long as wide; stem with broad-based prickles; flowers uniform; receptacle with a spine-tipped bract subtending and exceeding each flower.

Dipsacus

1. Involucral bracts without spine at the tip, the outer ones less than 3 times as long as wide (excluding marginal bristles); stem glabrous or hairy but not prickly; flowers various; receptacle merely hairy or with short spineless bracts.

2. Leaves (at least middle ones) pinnately lobed; stems pubescent; flowers toward outside of head distinctly larger (and showier) than central flowers; calyx bearing 8 (or more) prominent but deciduous awns; receptacle hairy but without bracts; achenes hairy, obscurely 4-ribbed.

Knautia

2. Leaves unlobed (± lanceolate and nearly or quite entire); stems (not peduncles) glabrous (or finely pubescent at the nodes); flowers nearly uniform in head; calyx very short, awnless; receptacle with bracts shorter than achenes; achenes glabrate, strongly 8-ribbed.

Succisella