Acanthocephalus

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Distribution

Asia-Temperate: Afghanistan (Afghanistan ‒ native); Iran (Iran ‒ native); Kazakhstan (Kazakhstan ‒ native); Kirgizistan (Kirgizistan ‒ native); Tadzhikistan (Tadzhikistan ‒ native); Turkmenistan (Turkmenistan ‒ native) Asia-Tropical: Pakistan (Pakistan ‒ native)

Description

Capitula small, with fruits globose-pyriform. Outer involucral bracts herbaceous, lanceolately linear, inner firmly connate into hard (with fruits) convex shell, open at the top, covered with short, light colored or long acicular spine (spines sometimes absent); apices of inner involucral bracts free, herbaceous, linearly lanceolate, covered with occasional small spines or smooth. Florets yellow, exserted from open top of connate involucral bracts of capitulum. Achenes laterally compressed, more or less curved, with short beak at the apex carrying inconspicuous pappus in form of five-toothed crown or small expansion.

from: Bobrov, E. G. & Tzvelev, N. N. (ed.) 2000: Flora of the USSR XXIX, Compositae, Tribe Cichorieae. – Enfield.

Chromosome numbers

The single chromosome count of 2n = 18 (Podlech 1974) for Acanthocephalus benthaminanus is puzzling. A basic number of x = 9 is unknown in Crepidinae, therefore Lack (2006) suggested a hexaploid cytotype with a basic number of x = 3.A,B

Bibliography

A. Lack H. W. - Cichorieae in Kadereit J. W. & Jeffrey C., The families and genera of vascular plants 8. 2006
B. Podlech D. & Bader O. in Mitt. Bot. Staatssamml. München 11: 457-488. 1974