34. Raphanus L. (radish)
Plants annual or biennial, terrestrial, usually sparsely pubescent with
unbranched hairs. Stems erect or ascending, usually branched. Leaves alternate
and basal, nearly all petiolate, the upper leaves progressively reduced, the
bases not clasping the stem, pinnately lobed or divided, the 5–15 lobes
progressively larger toward the leaf tip, the margins otherwise toothed or
lobed. Inflorescences panicles, the lower branches subtended by reduced leaves,
the flowers bractless. Sepals erect or ascending, narrowly oblong to
oblanceolate or nearly linear. Petals unlobed, purple, pink, white, or light
yellow, with dark purple veins. Stigma not lobed. Fruits more than 5 times as
long as wide or rarely less, ascending, straight or nearly so, circular in
cross-section, often corky in texture, segmented into apical and basal
portions, the basal portion relatively short, seedless, and stalklike, the
apical portion 4 or more times as long as the basal portion, tapering in the
apical 1/4–1/2 to a distinct, conical, seedless beak in addition to the style,
indehiscent or eventually breaking between the seeds into 1-seeded segments.
Seeds in 1 row in each locule, 2.0–3.5 mm long, oblong to nearly circular in
outline, the surface with a netlike or honeycomb-like pattern of ridges and
pits, reddish brown. Three species, Europe, Asia, Africa, introduced nearly
worldwide.
The fruits of Raphanus are unusual in that the seeds are effectively in
a single vertical rank and are immersed in corky tissue. Thus, there are no
locules in the mature fruit. The reduced basal segment usually contains
vestiges of the replum.