274 



THE JOURNAL OF BOTANY 



genera upon the difference in character of the perianth, those species 

 in which the segments of the perianth are free down to the top of the 

 ovary being regarded as Vellozia, while Barbacenia comprises those 

 in which they unite to form a distinct tube. 



The grouping of the Velloziea? has hitherto been based upon the 

 character of the caudex taken in conjunction with that of the leaves, 

 perianth, or ovary-surface. A careful study of many species seems 

 to indicate that the outgrowths present on the external wall of the 

 ovary are sufficiently constant and characteristic to afford a simple 



Fig. 2. — Section showing three stages (A, B, C) in growth of hairs on 

 surface of ovary of V. Eylesii (highly magnified). 



and 



of 



and convenient method of grouping, and in some cases even 

 identification, of the different species. 



All these outgrowths are subepidermal in origin, and are composed 

 of a central mass of cells surrounded by a single layer of epidermal 

 cells, which is continuous with the epidermis of the ovary wall. 

 Each outgrowth arises as a small papilla of hypodermal cells imme- 

 diately below the epidermis. The cells rapidly increase in number 

 and frequently in size, the growth of the epidermis keeping pace with 



