70 THE NATURE-STUDY OF PLANTS 
floating for months. They ripen in the early autumn, 
but they do not, as a rule, germinate until the late 
spring, and sometimes not for eighteen months or two 
years, during the whole of which time they may remain 
afloat, so they stand a good chance of being carried 
many miles on the bosom of even a very slow stream. 
A heavy fall of rain will wash many seeds down a 
slope, even a gentle one, and the cascades which are 
such an attractive feature of some of our hilly or 
mountainous districts after a downpour, are, within 
their own limits, as effective as the rivers, and very 
much more rapid. 
I drew attention in the last section to the fruits 
which open in dry weather and close up again when it 

Fia. 22.—The Brooklime. 
A, the fruit after dehiscence, x 3; B, a fragment of a a leaf 
with three of the seeds adhering to it; S, seed. x 
is wet: there are, on the other hand, a few that 
remain closed, or do not open sufficiently widely when 
dry to give the seeds any chance of escaping. The 
Self-heal and the Brooklime respectively afford a 
common instance, and, although they differ very 
widely in detail, neither of them parts with its seeds 
