Dipsacus L.
Biennial herbs; stems prickly and often grooved, ± erect and branched above. Lvs opposite, crenate-serrate to entire, often prickly. Infl. a globose to cylindric capitulum; involucral bracts linear to lanceolate, each with a prominent apical spine; receptacular scales subtending each fl., spine-tipped. Involucel ± 4-angled, ending in a short ± 4-lobed cup. Calyx ciliate, persistent at fruiting. Corolla usually 4-merous, long-tubular, zygomorphic. Stamens 4. Fr. 4-angled, with appressed hairs.
Key
1
Involucral bracts linear, curved upwards, the longest often > capitulum; receptacular scale with straight or slightly recurved, flexible terminal spine > floret
Involucral bracts lanceolate-subulate, ± patent, much < capitulum; receptacular scale with recurved, rigid terminal spine = floret
c. 15 spp., Eurasia, tropical Africa, mostly Mediterranean. Naturalised spp. 2.
