Rapistrum


Rapistrum, the bastardcabbages, is a genus of the family Brassicaceae with a distinctive cross like arrangement of its petals. Species of Rapistrum are annual to perennials. The yellow petals are accompanied by sepals that stand vertically at near right angles. Leaf shape and arrangement varies from rough toothed to a configuration of opposingly lobed pairs along the plant stalk, pinnately lobed.

Fruit

The genus Rapistrum has a characteristic fruit comprising two segments:
a) The distal
The part of the fruit farthest away from the point of attachment. The distal is endowed with a ribbed spheroid base that tapers to form a narrowed projection. It holds a single seed.
b) The proximal
The part of the fruit nearest to the point of attachment. Possesses a more uniform narrower shape compared to the distal above, giving the fruit a waist. It holds a maximum of three seeds, more commonly none or one.
The fruit varies from species to species. The distal of R. rugosum is strongly ribbed and narrows to form a beak whereas R. perenne is comparatively less wrinkled and ends with a style that stubbornly resists detachment, 'a persistent style'.
When ripe the distal breaks away in an across-wise fashion, breaking transversely.