CRUCIFER^ 



89 



embryo occupies the whole of the seed, there being no 

 endosperm. In L. sativum (Fig. 50) the seed is of the 

 same form, but nearly twice as thick; if, therefore, 

 the cotyledons were to occupy the whole additional 



Fig, 49. — Section of seed of Lepidium 

 graminifoUum. x 15. 



Fig. 48. — Seedling of Cress 

 sativum), x 3. 



lujn Fig. 50. — Section of seed of Lejndium 



sativum. X 15. 



space, they would become extremely thick. In endo- 

 spermic seeds this would be simply filled by endosperm. 

 In Lepidium, however, this device cannot be resorted 

 to ; but the two lobes just fill up the vacancy. 



Cakile 



0. maritima. — -A sea-shore plant. The anthers of the 

 long stamens project above the flower, so that the pollen 

 would fall just on to the stigma. At the same time 

 cross-fertilisation is also provided for. The flower has a 

 sweet scent, and four nectaries, two at the base of the 

 short stamens, two at the base of the longer ones. 

 Some fifty insects are on record as visitors. As in 

 so many other seaside plants, the leaves are fleshy. 

 M. Lesage has found that the leaves of several inland 

 plants tend to become fleshy if they are treated with 

 water containing salt.^ 



^ Constantin, La Nature tropimle. 



