Chap. IV. OXALIS, HOMOSTTLBD SPECIES. 181 



propagated a sexually. It is probable that this kind 

 of propagation would be much aided by there being 

 no expenditure in the production of seed. 



Oxalis {Biophytmn) sensitiva. — This plant is ranked 

 by many botanists as a distinct genus. Mr. Thwaites 

 sent me a number of flowers preserved in spirits from 

 Ceylon, and they are clearly trimorphic. The style 

 of the long-styled form is clothed with many scattered 

 hairs, both simple and glandular ; such hairs are much 

 fewer on the style of the mid-styled, and quite ab- 

 sent from that, of the short-styled form ; so that this 

 plant resembles in this respect 0. Valdiviana and 

 Begnelli. Calling the length of the two lobes of 

 the stigma of the long-styled form 100, that of 

 the mid-styled is 141, and that of the short-styled 

 164. In all other cases, in which the stigma in this 

 genus differs in size in the three forms, the differ- 

 ence is of a reversed nature, the stigma of the long- 

 styled being the largest, and that of the short-styled 

 the smallest. The diameter of the pollen-grains from 

 the longest stamens being represented by 100, those 

 from the mid-length stamens are 91, and those from 

 the shortest stamens 84 in diameter. This plant is 

 remarkable, as we shall see in the last chapter of 

 this volume, by producing long-styled, mid-styled, 

 and short-styled cleistogamic flowers. 



Homostyled Species of Oxalis. — Although the majority 

 of the species in the large genus Oxalis seem to be 

 trimorphic, some are homostyled, that is, exist under 

 a single form ; for instance, the common 0. aceto- 

 sella, and according to Hildebrand two other widely 

 distributed European species, 0. strieta and cornieulata. 

 Fritz Miiller also informs me that a similarly consti- 

 tuted species is found in St. Catharina, and that it is 



