Ne 
; 
i 
i 
‘ 
rti 
bear coloured flowers and exalbuminous seeds: but on co 
THE DISPERSION OF BRITISH PLANTS. 253 
circumstances might be suggested as possibly exerting a counteracting 
influence ; he 
ra mparing 
Composit by themselves, in which all the conditions referred to are 
simi] ar, we find 
pecies. Average. 
81 Furnished with feathery pappus  . . 5°98 
2 With grappling organs. , ‘ ; 9.50 
14 Without pappus_ . : , ve? 8186 
Dispersion according to Character of the Seed. 
sta.—Differences in the seed deserve our special attention, for it 
carried fr 
better to withstan the various vicissitudes to which it must ye eX- 
ing transit, or to establish itself and maintain a footing in 
sed during 
the struggle for existence when it has reached a new country, the 
effect may be traceable in the specific area. We have already seen 
fluence. It might 
be anticipated that a thick, hard, leathery, or crustaceous testa would 
: 76 
7 AP : ihe j 
on the Action of sea-water, seeds endued with a thick testa, e. +, of 
Leguminose and Hibiscus, were amongst the earliest to lose their 
nd, or @ soft cellulose or mucilaginous testa on the other. Omitting 
*Pecies in which the nature of the testa is doubtful, we have :— 
665 With testa thin or membranous 
47 With testa soft cellulose, &e . : : : 
192 With testa thick, leathery, or crustaceous 6°05 
Pe Albumen.—If the function of albumen be to supply nourishment 
the embryo during germination, its possession may enable a seed to 
retain its Vitality longer, and maintain its existence more sturdily 
os it reaches a new country, than a seed in which no such store 
urishment is provided, and thus favour the dispersion of the 
* A > 2 
an oping, Hooker, in bis paper on the flora of the Galapagos Islands, expresses 
4 ih resistin i a the “indurated sved-coats of some’ (plants) probably ai ae 
Some time the effects of salt-water.” 
