146 BRITISH FLOWERING PLANTS chap. 



and fruit dark purple. The flowers in both species are 

 small and greenish. In R. Frangula the petals, teeth 

 of. the calyx, and stamens are 5 in number ; in R. 

 catharticus the parts are in fours. 



R. catharticus. — The flowers are dioecious, each con- 

 taining the rudiments of the other sex ; the male is 

 larger than the female. They are sweet-scented, but 

 not much visited by insects. Darwin distinguishes 

 four forms — (1) a long-styled male, (2) a short-styled 

 male, (3) a long-styled female, and (4) a short-styled 

 female. 



R. Frangula. — The flowers are complete, and more or 

 less protandrous. Honey is secreted by the inner surface 

 of the calyx. The petals are small, and each covers one 

 of the anthers, forming a sort of small cap. The anthers 

 are at about the same level as the stigma, and as they 

 open inwards insects coming for the honey would touch 

 them with one side of the head, and the stigma with 

 the other, thus probably efi"ecting cross-fertilisation. 



According to Warnstorf, the flowers in the neigh- 

 bourhood of Ruppin are homogamous. Schulz states 

 that in some districts the pistil is longer than in others. 

 They are visited by bees, humble bees, wasps, and flies. 



LEGUMINOS^ 



We now come to the great and interesting order 

 Leguminosge, which falls into three groups, of which one 

 only, the Papilionacese, is represented in Britain. Of 

 this we have eighteen genera. The flowers, says Ben- 

 tham,^ are " in axillary or terminal racemes or spikes, 

 rarely solitary. Sepals combined into a single calyx, 

 more or less divided into 5 or fewer teeth or lobes. 

 Corolla very irregular, consisting of 5 petals. The 

 upper one, called the standard, is outside of all in the 



' Handbook of the British Flora. 



