Fructification of the submersed Algce. 501 
ture, of being nourished by absorption ; their embryos are 
hatched in the same element, and equally surrounded by a te- 
nacious mucous substance, without any exterior coats. If the 
spawn of. frogs be eggs, the grains of these plants must be 
seeds. 
The third objection, very far from being an urgent one, is, 
I am persuaded, a capital reason to believe that the seeming 
lateral internodia of the Confervas, since they are capable of 
cohering two or more together, and produce only one indivi- 
dual, are true seeds, and not gems. The coherence of two 
living embryos, whether gems or seeds, may form monsters, 
but it is equally impossible, in both cases, that perfect indivi- 
duals should regularly be formed by such coalition. Observa- 
tion daily shows, that of two or more neighbouring gems or 
seeds, one may thrive by rendering the other abortive; but, in 
this case, gems never cohere, the abortive one falls. In seeds, 
on the contrary, not only the abortive coheres to the thriv- 
ing one ; but this abortion happens oftener in the several 
species of plants, in proportion as the seeds, by their situation, 
are apt to cohere. In some genera it is even a regular pro- 
ceeding of nature, as in the Dalea, Lagoecia, Hasselquistia, Sa- 
pindus, Ornitrophe, &c. 
These objections having been I hope satisfactorily answered, 
I do not hesitate to consider these grains of the subrnersed 
algae to be, what obviously they seem, their effective seeds. 
The figure, formation, and temporary fall of these bodies, would 
never have left any room for the above doubts, if their fecun- 
dation had been easily accounted for. This point we must now 
proceed to investigate, and examine whether the mucous 
