New and Little Known West-Himalayan Liverworts. 321 
The plant is decidedly more xerophilous than P. appendiculatum 
and is also smaller and thinner. It is repeatedly forked and may 
be up to 2-5 cm. in length and 8 mm. in breadth. The lobes are 
oblong-obovate, dark green above with conspicuous stomata, and 
purple below. Each stoma has three series of cells surrounding it 
with seven or eight cells in each series. The purple scales (Fig. 6, d) 
are overlapping, similar to those of Reboulia hemispherical and 
each has two or three long narrow purple appendages which bend 
over the growing point. The scales do not reach more than half 
way to the margins. The vegetative thallus and the tissue of the 
female receptacle contain numerous brown oil-cells. They are 
specially numerous in the latter where they occur among the 
epidermal cells. The thallus produces ventral adventitious shoots. 
Eig. 8. Plagiocliasma avticulatum: a, b, plants with carpocephala, ax 2, 
b x 1 ; c, lobe with male receptacle, X 2. 
P. arliculatum is monoecious. The antheridial receptacles may 
be formed one after another, or an antheridial receptacle may be 
followed by a female receptacle. The antheridial receptacle is a 
horse-shoe shaped structure surrounded by small scales as in P. 
appendiculatum with two growing points. The female receptacle is 
also similar to that of the last-mentioned species but it has never 
more than four involucres, usually it has only one to three (Fig. 8). 
The dorsal surface of the female receptacle is slightly concave but 
it has the barrel-shaped pores as is the case also with P. appendix 
culatum. The pores on the male receptacle are simple. Plagio- 
chasma, therefore, lags behind Reboulia in this respect among others, 
that the male receptacle has simple pores in Plagiocliasma, but the 
pores are barrel-shaped in Reboulia , 2 The aestivation of the 
involucre has already been described. The spores are closely 
reticulate, lamellate, 60 to 80 /a in diameter. The elaters are 
normally bispiral, 220 to 260/a in length. 
1 Cavers, “ Inter-relationships of the Bryophyta,” Fig. 20, b, c (p. 39 of 
Reprint). 
* Cavers, “On Rebouliahemispherica,” Naturalist, 1904 ; “Inter-relationships 
of the Bryophyta,” 1911, Figs. 22, 23. 
