Nature of aerial Tubers in Dioscorea saliva , Linn . 493 
Hooker 1 says the underground tubers are ‘ large, and 
variable in form,’ the stem ‘ bulbiferous.’ 
Bentham 2 says, f stems from a tuberous rhizome, elongated 
and twining, often bearing green globular bulbs in the axils of 
the leaves/ 
Again he says 3 , ‘ Stems glabrous, often bearing green 
globular bulbs in the axils of the leaves.’ 
Trimen and Hooker 4 note that the Hoot-tubers are very 
large, globose or elongate, stem . . . tuberiferous in the leaf-axils.’ 
The writer of the article in the Dictionary of the Economic 
Products of India does not mention the tubers of D. sativa , 
but he notes that in Malabar and Travancore there are two 
species which bear, on the stems, tubers which are ovate 
in shape, and which vary in size from about that of a pea, 
to three inches in diameter. These axillary tubers are eaten, 
but are chiefly used for ‘ seed.’ These species, however, he 
identifies with D. alata. 
In the Stove at the Cambridge Botanic Garden there is 
a plant of D. sativa which produces in the axils of the leaves 
of its annual shoots, large rounded tubers, six or more inches 
in diameter and weighing as much as a pound or a pound and 
a half each. When mature these tubers are greyish or brown 
in colour, and present depressions in the surface which bear 
resemblances to those containing the ‘ eyes ’ in a potato. 
In addition to the tuber, the leaf-axil bears several (in some 
cases as many as eight) long, and very slender, pendulous 
spikes of flowers. It may be noted that these flowers are 
structurally hermaphrodite, although those in the wild forms 
of the plant are unisexual. Wight 5 also notes that when 
cultivated, the flowers tend to become bisexual. 
In order to observe the mode of origin and structure of the 
axillary tubers, successive series of sections were cut with 
a microtome. The plane of the sections is that which is 
1 Hooker, Flora of British India, vol. vi, p. 295 (*94). 
2 Bentham, Flora Australiensis, vol. vi, p. 461 (’73). 
3 Bentham, Flora Hongkong., p. 368 (’61). 
4 Trimen and Hooker, Flora of Ceylon, vol. iv, p. 278 (’98). 
5 Wight, Ioones, vol. iii ; Description of Plate 878. 
