Nellie Carter . 177 
ON THE CYTOLOGY OF TWO SPECIES OF 
CHAR A CIOPSIS. 
[With Three Figures in the Text ] 
By Nellie Carter, M.Sc. 
I N November, 1918, a collection of epiphytes was made from a 
small stagnant rain-water pool in Pool Hollies Wood at 
Sutton Park, Warwickshire. The fallen leaves lying in the water 
were covered with a pale blue-green incrustation, which proved on 
examination to consist almost entirely of two species of Charnciopsis 
Bora, together with developmental stages of spores of Micro- 
thamnion and filamentous bacteria. One of the species of 
Characiopsis was identified as Ch. Nccgelii (A.Br.) Lemm., but the 
other has never previously been recorded, and is therefore 
described here as a new species under the name of Ch. saccata. 
Since the material was available in considerable quantity a 
study of the cytology of the two species has been made, and 
several interesting facts have been revealed. Thus the great 
difference in the internal structure observed in these two species 
belonging to the same genus is rather surprising, and not what one 
would have expected. This difference is obvious, even in the living 
condition, and although in the case of very young individuals the 
size and shape of the cell is often similar in both species, there is 
no possibility of confusing them. 
The larger species, Ch. Ncegelii, varied in size from 16-50/x 
long and 6-28/x broad, and the individuals were usually oval, 
elliptical, or sometimes subspherical in shape, and except in the 
case of very young individuals the apex of the cell was always 
broadly rounded (Fig. 1, A-G). 
The smaller species reached in fairly large specimens a 
length of 82/m. and a breadth of 15-16/x, but in this case there was 
very much more variation in the shape of the individuals 
(Fig. 2). Usually they were somewhat lanceolate, the apex being 
distinctly acuminate (Fig. 2, E, I, L, M and P). It not 
unfrequently happened, however, that distorted forms occurred, 
in which the cells were rather irregular in outline, being very 
often more or less triangular (Fig. 2, A-D, F, G, H and J). 
These abnormal forms were very common amongst the smaller 
individuals, although occasionally some of the larger specimens 
also showed similar distortions. 
In both species there is a very distinct, though short basal 
stalk, with a disc-like holdfast by means of which the organism is 
attached to the substratum. In the case of the triangular forms, 
