Germination of the Seeds of Aquatic Plants. 355 
There are, in fact, a large number of land-plants, not merely 
those which frequent the river or pond side, but plants so 
diverse in their stations as Arenaria peploides, Symphytum 
officinale, and Rhinanthus erista-galli, and many of the British 
Labiate of the roadside and waste-ground, that in their 
ability to germinate in water and in the early growth of the 
seedling behave practically like aquatic plants. I found water 
the best medium for procuring the germination of plants of all 
kinds of stations, and certainly the best for the observation of 
the germinative process and of the growth of the seedling.’ 
The results of the experiments on the effect of light on 
germination in water may be thus summed up. With 
Ranunculus hederaceus, R. sceleratus, Nasturtium officinale, 
Hottonia palustris, Callitriche aquatica, Juncus communis, 
and J. glaucus, darkness was decidedly repressive in its 
influence. Whilst a large number and often all the fruits or 
seeds germinated in diffused light, very few and often none 
germinated in the darkness. But when the darkened vessel 
was uncovered, germination commenced briskly in a few 
days, and in a short time most if not all the seeds or fruits 
were germinating. It has been shown that diffused light 
also favours the germination of the seeds of Nuphar luteum, 
although darkness does not repress it. On the other hand, 
darkness favours the germination of the fruits of Potamogeton 
natans more than light. The fruits of Myriophyllum alterni- 
florum, M. spicatum, Stellaria aquatica, and S. media germi- 
nate equally well both in light and darkness. By placing 
the vessels side by side, the same thermal conditions, as 
indicated by the thermometer, were obtained. 
In conclusion, one or two general remarks may be made 
on the capacity of the seeds or fruits of aquatic plants to 
withstand drying. It will have been already observed that 
almost all of them can retain their powers of germination 
after a winter's drying. But the experiments were not often 
sufficiently extended to test this capacity beyond four or five 
months. It has been shown, however, that in the case of 
1Some of the facts dealt with in this paper were given in a paper read 
before the Royal Society of Edinburgh about two years ago, but not yet 
published. 
VOL. XIII. 2B 
