190 M. C. Stopes. 
river banks, right down to the old waters-edge and yet there 
appeared to be only one plant in the bed of the stream, and this did 
not dower. 
The list of Bryophytes is exceedingly short, as was the life of most 
of them; it only comprises Marchantia, a small moss that never reached 
maturity, and Funaria hygrometrica. The Algae were represented by 
Vnucheria and Botrydium granulatum on the mud, and Cladophora 
in a little pool near the spring. 
I think this is rather remarkable, as there were seemingly such 
splendid opportunities for mosses and algae on the sides of the deep 
cracks, which were quite moist, and protected from sun and wind. 
At first there appeared to be but little struggle between the land 
plants and the water plants, there was plenty of room for each, for 
most individuals were solitary with considerable tracts of bare mud 
round them; for the water plants the struggle was against the 
adverse condition of being without water and exposed to sun and 
wind, and for the land plants it was primarily a test of dispersal 
and of suitability to the conditions. The distribution of the 
Polygonum is perhaps worth noting, as it was so diagrammatic at 
first. It always chose the exposed bank of the stream, as is 
seen from the diagram, where the dotted patches represent the 
growths of Polygonum, and the crosses, bushes or tall reeds 
Where a bush was on the exposed side, and so would afford shelter, 
it caused a gap in the growth at that place. 
Fig. 1. Diagram illustrating distribution of Polygonum 
lapathifolium along sides of river-bed. 
