114 ME. C. B. CI/AHKE ON INDIAN BEGONIAS. 



J 



On Indian Begonias. By C. B. Clabke, M.A., F.L.S. 



[Read December 4, 1879.] 

 (Plates I.-III.) 



The present paper is supplementary to the account of the Indian 

 Begonias in Sir J. D. Hooker's ' Flora of Britisli India,' ii. 635- 

 656 ; but although principally confined to Indian species, I have 

 also looked over all the species of the Order in the Kew Herba- 

 rium. The Order comprises two genera of one species each, viz. 

 Hillebrandia and Begoniella ; and about 350 other species are re- 

 ferred to the genus Begonia in Bth. & Hook. Gen. PI. i. 841. It 

 is with the general principles on which these species are to be 

 arranged that the present paper deals. 



Alph. DeCandolle, Prodr. xv. pt. i. 267-408, divides them into 

 3 genera, viz. Mezierea, Casparya, and Begonia. Mezierea (3 

 species) is separated only by the ovary being " before flowering 

 unilocular;" but Hk. f. remarks that, in the two Indian species, the 

 placentation nowise differs from that of Begonia. I have found (in 

 numerous examinations of fresh specimens) that the placentae do 

 not quite meet in the young ovary, but the fruit is completely 

 2-celled (PI. III. figs. 33, 34) ; these two Indian Meziereas are 

 therefore Begonias of the section Platycentrum or very near 

 thereto. It is clear that A. DC. possessed insufficient material 

 of these species ; for he discarded Wallich's original specific name 

 of gigantea as absurd (" nam inter Begoniaceas minime gigantea "); 

 it really is the largest among the 64 Indian species. 



A. DCs other genus Casparya comprised 14 South-American 

 and 4 Javan species ; it was separated from Begonia by the cha- 

 racter that the capsule dehisces dorsally, exactly up the angles or 

 wings, and not, as often as in Begonia, by elliptic lines on the 

 faces. To this genus A. DC. doubtfully appended 3 (of which 2 

 were one) Indian species, remarking that their place was doubt- 

 ful because the dehiscence of their capsule was unknown. Their 

 fruit is now found to be baccate indehiscent, as stated by Hk. f. 

 as one of the reasons why he abandons both the genus Casparya 

 and the dehiscence of the fruit as a primary character in dividing 

 Begonia. Hk. f. also states that he has found in one species the 

 capsule dehiscing sometimes along the angles, sometimes along its 

 faces ; this I have never been able to see. In Bth. and Hk. f. 

 Gen. PI., therefore, Klotsch's plan is followed in the main ; the 

 styles with the complication of their stigmas and the stamens 



