New and Little Known West-Himalayan Liverworts. 211 
from the rest is met with at or near the apex. All cells of the 
scales contain chloroplasts, as is the case with the scales of 
Monoselenium 1 and the young scales of Aitchisoniella. 
Both the thick-walled narrow and thin-walled wide rhizoids 
are present, but the former do not possess the pegs and are much more 
numerous than the latter. There is no distinct midrib in the thallus. 
The ventral pores, apart from their absence in other 
Marchantiales, are interesting in another respect also. Filaments 
of Oscillatoria and small colonies of Nostoc which grow near the 
plants often find their way into the thallus-chambers through them. 
In one case even small eggs of some animal were found inside the 
chambers. This connection between Cyathodium and the blue- 
green algae mentioned above seems to be quite accidental, but it 
suggests the method by which a permanent connection may have 
been established between Authoceros and Nostoc . 2 
The ventral pores seem to have been produced in order not to 
reduce the area of the upper surface available for the absorption of 
the small amount of available light and at the same time to provide 
for adequate gaseous exchange. 
The apical parts of the sterile plants and the sterile branches 
of male plants become transformed into tubers about the end of the 
rainy season, i.e., about the end of August. Short pointed thick- 
walled hairs begin to appear on the margins and the ventral and 
dorsal surface of the thallus, a short distance behind the apex. 
The thallus itself becomes very much denser than it was before 
near the apex. On the anterior margin there is one growing point 
which in many cases forks into two before tuber formation. The 
air chambers are small and numerous and divided by horizontal 
septa so that there is more than one layer of them (Fig. 1, e). 
There are no pores. The mature tuber (Fig. 1, /) is about I mm. 
long and a little broader, firmly fixed to the substratum and covered 
dorsally and laterally by numerous forwardly directed spike-like 
hairs, and ventrally by similar hairs and rhizoids. These hairs are 
obviously modified rhizoids. On the ventral surface there are a 
few scales. The cells of the tuber contain numerous chloroplasts 
and some starch. There are one or two growing points on the 
anterior margin. The margins of the tuber are directed obliquely 
upwards, so that there is a groove in the mid-dorsal line. 
' Goebel, loc. cit. 
2 Cavers (Ann. Bot., vol. 18, 1904, p. 91) describes the occurrence of 
Nostoc chains in the ventral tissue of Fegatella and several other Marchantiales. 
It would be interesting to know whether these forms also possess ventral pores. 
