3 20 Shiv Ram Kashyap. 
diagrams (Pig. 7). In Reboulia hetnispherica the margins are similarly 
bent inwards at first but later they become perfectly free and are 
pushed outwards. It would be interesting to know if this is a 
constant feature of the genus Plagiochasma. The writer has examined 
only the above-mentioned three species and every involucre examined 
has shown this arrangement of the involucre margins. When the 
number of involucres is large, as in P. appendiculatum , the free 
margin usually belongs to the same side of the several involucres. 
In one case, when the receptacle had nine involucres, all with ripe 
sporogonia, eight of them had the free margin on the same side ; 
the ninth had the free margin on the other side, so that here the 
two free margins belonging to the adjacent involucres were close to 
each other, while in the rest the free and folded margins alternated 
with each other. 
the involucre in Plagiochasma ; for description see Text. 
The lid (operculum) of the capsule is three cells in thickness 
and these cells are equally thickened on all sides (Fig. 6, c). Some¬ 
times, when the plants occur in dry exposed places, the capsule 
becomes dry very early and the elaters remain without any spiral 
bands though they have thick brown walls. This condition of the 
elaters is met with much more often in P. articulatum. The size 
of the spores and elaters as given by Stephani is 51/a and 250/a 
respectively. The writer found that the spores and elaters in one 
capsule were often 60/a and 220/a respectively. This relation between 
the size of the spores and elaters is found in other species also, 
e.g., Targionia hypophylla , an increase in the size of the spores 
being accompanied by a decrease in the size of the elaters. 
Plagiochasma articulatum Kashyap. 
This species was often found growing along with P. appendi- 
culatum, and forms along with the latter one of the commonest 
thallose liverworts in Mussoorie. It also occurs, however, in exposed 
and dry places where the latter cannot live. A few plants of both 
species are found in winter, about December and January, on the 
river bank in Lahore also, but they never produce any fruit here. 
They probably arise from the spores brought down by the water 
from the hills. 
