220 
Shiv Ram Kashyap. 
end of the season when only a few plants would be alive. Secondly, 
this plant resembles a Riccia with which it was found growing and 
is very small so that it can be easily overlooked or mistaken for the 
Riccia, especially in the sterile state. 
The thallus is dichotomously divided but sometimes the 
branches are so placed that the branching appears to be pinnate. 
The lobes are about 4 mm. long and at most 2 mm. broad, and are 
oblong-ovate with a small depression at the apex (Fig. 3, a to d). 
The plants have a light-green, rather greyish colour. The dorsal 
surface is perfectly smooth, no raised pores or areoles being visible. 
The pores, however, are present, being very minute, very little 
raised, simple and of the type found in the Astroporeae. Each pore 
is surrounded by a single ring of six cells which have slightly 
thickened radial walls (Fig. 4, a). The cell walls of the rest of the 
uppermost layer are quite thin. A thin membrane projects far 
towards the centre of the pore from the margin (Fig. 4, a). The 
pores are pretty numerous and each leads to an air-chamber below. 
The chambers have no assimilating filaments and are in one or two 
layers especially well seen near the margins where the part of the 
wing forming the floor of the lowermost chamber is reduced to a 
single layer of cells. The chambers are quite small. They are 
directed forwards and for this reason a transverse section of the 
thallus shows several layers of these chambers but a longitudinal 
section shows mostly a single layer (Fig. 4, b, c). The ventral 
surface is hyaline or bluish. The thick midrib projects strongly 
below and the thallus is continued into the thin wings abruptly as 
seen at some distance behind the apex; near the apex the midrib 
gradually passes into the thin margins (Fig. 4, a, e). The rhizoids 
are attached to the midrib and are of both smooth and tuberculate 
kinds. The scales are arranged in two rows on the sides of the 
midrib so that the latter is not covered by them. They are small, 
distant, hyaline or bluish and do not project beyond the margins. 
Each scale is triangular or lunate and has an apical filamentous 
appendage of three to five cells. The cells of the young scales 
contain some chloroplasts. The terminal cell of the appendage 
contains mucilage and similar mucilage cells are also found pro¬ 
jecting from the margins, and a few such cells are even found in 
the body of the scale (Fig. 4, d, e). Such mucilage cells in the body 
of the scale have also been observed by the writer in the scales of 
Plagiochasma appendiculatum and P. articulatum. The appendage 
of the scales bends over the growing point and protects it. The cells 
