RICCIA CROZALSII IN BRITAIN 105 
numerous papille within. Epidermal cells not incrassate or 
mamillate. 
In his additional notes Dr. Levier says that at first sight the 
plant recalls R. ciliata Hoffm., which is also a monoicous species 
and belongs to the ciliate group. It grows in similar habitats, 
and resembles a small form of the latter ee shorter hairs. en 
single fronds, however, are examined, even with a lens, the 
resemblance disappears. In R. Crozalsi the postical sides are of 
a purple colour and not green, and the margins muc 
thickened. A transverse section tas the see and sige 
to be almost equal, sy peraee the proportion in R&, ciliata is as 
three is to one. The frond also in the latter spasies bias the & me 
thickness from apex es task: so that the upper and lower sided are 
parallel. Further, the spores in R. ciliata measure from 75-90 p, 
and the border is transparent and wider, furnished with more 
numerous, ee and generally truncate papille. 
fi. at var. ciliaris, which has been found-to. be identical 
with FR. twm a and Rf. palmata, differs in the dioicous inflorescence. 
It is twice as large, and the margins are more tumid, a goer 
the same thickness all along the sides of the frond. In our plant 
the borders become thinner or the base. The spores of the 
former are about 100 p» in diamete 
R. Lescuriana Aust. (£. glaucescens Carr.) may be known from 
R. Crozalsit by its larger size, thicker and more swollen edges, 
and single row of cilia. It is often, Serer almost glabrous ; in 
fact, this is the usual form met with in Britain. In section it is 
F 
epidermal cells of R. Crozalsii as sometimes mamillate. Levier 
iffn = ae not seen this character, nor do our forms 
appear to s 
Gonsiderspte difficulty, is often ae, in finding the 
antheridia in several species of Riccia. This is due to the fact 
that the ostioles only appear for a short Lee They may be 
easily seen, however, in transverse sections at the apex of the 
frond - nie shetae e gathered during the honk of November 
and Dec 
cca of the occurrence of R. Crozalsit in Italy 
0 
coloured sides. This grew in more shady situations. Another 
large plant growing in similar habitats and sent by M. Crozals 
from the South of France deviated somewhat from both of the 
