90 BRITISH FLOWERING PLANTS 



Crambe 



0. maritima. — This species is peculiar in having 

 the pod apparently stalked, owing to the lower joint 

 being seedless and consequently slender. The flowers 

 have a diameter of 12 mm. and form a large head. 

 The sepals support and enclose the petals, thus forming 

 them into a tube. The claws of the petals, the stamens, 

 and pistil are at first yellowish green, then clear violet 

 red. The anthers, however, are and remain yellow. 

 There are two large green round nectaries at the base of 

 the longer stamens, and two smaller at the base of the 

 shorter ones. The longer stamens terminate in two 

 projections between which the anther is seated. Knuth 

 supposes that they serve to guide the proboscis of visit- 

 ing insects. The flower is slightly protogynous, and 

 the stigma is ripe when the flower opens. The longer 

 stamens reach rather higher than the stigma. The 

 larvae of a small beetle (Meligethes) are often found in 

 the flower, feeding on the honey. Knuth thinks, how- 

 ever, that the injury thus done is more than compensated 

 by the part they play in fertilisation. 



The plant grows on sandy shores and stony places in 

 Western Europe. 



Eaphanus 



R. Raphanistrum. — A cornfield plant. The petals 

 are sometimes white Avith violet veins, sometimes light 

 yellow with dark yellow veins. The stigma is about at 

 the same level as the anthers of the shorter stamens, 

 which open inwards, so that self-fertilisation is ensured 

 in the absence of insects. There are four nectaries. 

 The pods when ripe have no longitudinal septum, 

 but the seeds are separated by a pithy substance. 

 The cotyledons resemble those of Brassica. The seed 

 (Fig. 53, A) is oblong, thick, and slightly narrower 

 at one end than the other. There is no endosperm, 

 so that the embryo occupies the whole seed, and as 

 this is somewhat deep, the cotyledons, in order to 



