New and Little Known West-Himalayan Liverworts. 2 13 
The growing-point was studied in these tubers and it was 
found to be occupied by a single initial cell. This cell has a 
triangular outline in vertical longitudinal sections, and it is oblong 
in horizontal sections. It cuts off segments dorsally, ventrally and 
laterally. Goebel 1 concludes from the figures of Leitgeb that a 
similar apical cell is present in the species investigated by the 
latter. C. cavernarum differs from the present species in having an 
apical cell cutting three segments (Lang). Vertical transverse 
sections showed that the tuber was two to four cells thick immediately 
behind the apical cell, without any spaces between the cells. A 
little further back spaces appear owing to the more numerous 
vertical walls in the upper and lower layers and horizontal walls in 
the middle layers. 
C. tuberosum seems to have lost all distinction between its 
upper and lower surfaces as shown by the position of the pores 
and the rhizoids. The biological significance of the pores has 
already been alluded to. The hairs on the upper surface of the 
tuber protect this region from drought. The part behind the tuber 
dies in a short time, and often the tuber is separated from the 
thallus by a constriction before maturity. 
The position of the male receptacle is variable, and is similar 
to the position of the female receptacles of Exormotheca and 
A itchisoniella. It may be terminal, lateral or in the angle between two 
sterile branches (Fig. 1, g to m), In the case where it is lateral 
the main shoot has divided into two branches, one of which grows 
on as an ordinary branch while the other forms the receptacle. In 
the case where the receptacle is in the fork the main shoot has 
divided into two, one of which again forks producing a sterile branch 
and a receptacle (Fig. 1, k). In both cases the receptacle has the 
form of a cushion separated from the thallus and a little raised by 
a stalk-like constriction. It is either circular in outline or elongated 
laterally and has a few scales on the ventral (anterior) side. Where 
the receptacle is terminal it is much more highly developed. It is 
raised upon a short stalk-like constriction which has a distinct 
groove on the anterior surface and is a branch-system. This last 
form of the receptacle is met with in plants which occur along with 
large female plants and are often concealed below the latter. In 
the case of the receptacle being lateral or in the fork branching has 
occurred, some branches being reproductive, others vegetative. In 
other plants atl branches are reproductive and we have a composite 
1 “ Organography of Plants.” Eng. Trans., vol. 2, 1905, p. 21. 
