some Indian Selaginellas. 689 
Vegetative branches of X. chrysorrhizos show this type of bulbil 
formation. Some of the lower branch-systems of the plants become 
elongated and filamentous, their leaves being much reduced, scale-like, and 
scattered (Plate XLIX, Fig. 2, and Text-fig. 4). In some cases the ends of 
these branches penetrate underground and become enlarged, developing 
numerous closely crowded, colourless scale leaves (PI. XLIX, Fig. 2, and 
Text-fig. 4 ; also Text-fig. 6). Professor Kashyap refers to the structures so 
formed as ‘ underground tubers in contradistinction to the ‘ surface tubers ’ 
of X. chrysocaulos. 
Sections (10 //, thick) were cut of tubers prepared with lactic acid, as in 
the case of X. chrysocaulos. These showed a large increase in the paren- 
chymatous tissue at the ends of the branches, the cells usually being densely 
Text-fig. 4. Selaginella chrysorrhizos. An ‘underground tuber’ showing the crowded scale 
leaves. Branches are indicated at B, and root-hairs developed from rudimentary rhizophores at A. 
The position of the tuber with regard to the elongated, filamentous vegetative branches springing 
from the base of the plant is also shown, x 4. 
filled with reserve food materials. The vascular tissue is comparatively 
small in amount, and in many cases lignification is not very strong, the two 
lateral protoxylems only being well differentiated. Text-figs. 5 and 6 
indicate the relatively small amount of vascular tissue present. The 
characteristic trabecular endodermis of the stem-stele may be recognized 
in the tubers (Text-figs. 5 and 6), as well as in the filamentous vegetative 
branches. The scale leaves of the stem-apex overlap closely (Text-figs. 4 
and 6), their bases often being rather enlarged and containing reserve 
materials. 
The tubers are dorsiventral in organization, and branching takes place 
repeatedly as in the surface tubers. A dichopodium is formed, the branches 
on alternate sides being more strongly developed ; 1 the ‘ lateral branches ’ 
thus formed are very short (Text-fig. 5, A and B, from a series of transverse 
sections of the same tuber ; also Text-fig. 6 , A and B, from another tuber). 
1 Cf. Hofmeister, 1. c., p. 382. 
