Description dandelion

Description

These are individual pollen grains of the dandelion – Taraxacum officinale.

Segment of pappus fiber showing barbs
The species of Taraxacum are tap-rooted, perennial, herbaceous plants, native to temperate areas of the Northern Hemisphere. The genus contains many species, which usually (or in the case of triploids, obligately) reproduce by apomixis, resulting in many local populations and endemism. In the British Isles alone, 234 microspecies are recognised in nine loosely defined sections, of which 40 are “probably endemic”.[8]

In general, the leaves are 50–250 millimetres (2–10 in) long or longer, simple, lobed, and form a basal rosette above the central taproot. The flower heads are yellow to orange coloured, and are open in the daytime, but closed at night. The heads are borne singly on a hollow stem (scape) that is usually leafless and rises 10–100 millimetres (3⁄8–3+7⁄8 in) or more[4] above the leaves. Stems and leaves exude a white, milky latex when broken. A rosette may produce several flowering stems at a time. The flower heads are 20–50 millimetres (3⁄4–2 in) in diameter and consist entirely of ray florets. The flower heads mature into spherical seed heads sometimes called blowballs[9] or clocks (in both British and American English)[10][11][12][13] containing many single-seeded fruits called achenes. Each achene is attached to a pappus of fine hair-like material which enables wind-aided dispersal over long distances.[citation needed]