It LEGUMmoS^ 163 



less the appearance of a strawberry. This may some- 

 times lead to the fruit being gathered and carried to 

 a certain distance. The swollen calyx would also 

 serve the same purpose in aiding distribution by the 

 wind. 



T. pratense (Purple Clover). — In this species the 

 nine under stamens have coalesced with the claws of 

 the keel and the base of the wings and standard, thus 

 forming a tube 9-10 mm. in length, at the end of which 

 is the honey, inaccessible therefore, excepting to humble 

 bees, hive bees, and Lepidoptera. According to Darwin, 

 it is self-sterile, which, however, Kerner denies. It is 

 said, however, to have produced no seed in New 

 Zealand until the colonists introduced humble bees. 

 Our commonest humble bee, Bombus terrestris, has a 

 proboscis just too short to reach the honey, but often 

 obtains access to it by biting a hole through the base 

 of the tube. The breach thus made is utilised by many 

 other insects. Knuth gives a list of those recorded by 

 -^-arious observers, amounting to over fifty. In America, 

 according to Eobertson,^ it is much visited by Lepidop- 

 tera. In Germany the numbers observed are 8 

 butterflies out of a total of 25 species ; in the United 

 States no less than 13 out of 20. It must, however, be 

 remembered that the United States are very rich in 

 Lepidoptera. The leaves are not wetted by rain, but 

 the moisture collects between the stipules, and is there, 

 probably, in part absorbed. 



T. incarnatum and T. medium agree in the above 

 points with T. pratense, but in the former the tube is a 

 little shorter. 



T. arvense (Hare's-foot Clover). — This happily named 

 species begins with a globular flower-head like its allies, 

 which, however, gradually elongates, forming a cylin- 

 drical column, like a soft brush, owing to the long fine 

 hairy teeth of the calyx. 



T. agrarium. — In this and some allied species the 

 corolla, which is at first yellow, turns brown, shrivels 



' Botanical Gazette, xvii. (1892), p. 177. 



