Germination of the Seeds of Aquatic Plants. 357 
Limnanthemum nympheoides, however, which frequents 
much the same waters as Nuphar lutewm and Nymphea alba, 
offers an apparent exception to this principle, since its seeds 
germinate after thirty months’ drying. Yet this plant on the 
muddy shores of ponds often lives like a land-plant. How 
little yet, however, do we know of the history of this and 
other dicotyledonous aquatic plants! If we could but pene- 
trate for a moment the black cloud that hides their past, we 
might become witnesses of some strange event in the history 
of plant-descent that would excite the intense interest of the 
student of plant-life. It may be that each dicotyledon 
among the aquatic plants represents a great catastrophe in 
some region of the earth’s surface where only the land-plant 
that was able to adapt itself to aquatic conditions survived ; 
and it may be that in the dicotyledons of the pond and of 
the river Nature has preserved mementos of these disasters. 
At all events, we can only follow with safety the sure road 
. of observation and experiment in approaching this mystery ; 
and however plausible they may seem, guesses in the dark 
can of themselves afford us but little aid. 
In the appended Table, I have selected from my experi- 
ments those most fitted to illustrate the postponement of the 
germinating process in water and wet mud. The capital 
letters in the last column signify as follows :— 
E implies that the experiment was brought to an end 
before all the seeds had germinated, and whilst 
some or all of the rest were still sound. 
P implies that the experiment is still in progress. 
R implies that the experiment was completed, the seeds 
that failed to germinate having decayed. 
S implies that the experiment was brought to a close in 
the spring, before all the seeds had germinated. 
1 Experiments extending over some years have been carried out by me, with 
the object of testing the capacity of Limnanthemum, Myriophyllum, etc., to 
acquire the habits of land-plants, 
