STRUCTURE OF SEED. 209 



mine the character of different parts of the seed of 

 Nuphar. 



It must be observed, that as germination has mos" 

 frequently been studied in the French-bean, Wheat, and 

 other plants with fleshy cotyledons, that which is only 

 true as regards this class, has, in general, been too 

 readily extended to all. 



Foliaceous cotyledons are, on account of their nature, 

 always destined to come out of their envelope, and also 

 above ground, at germination ; but it is not the same 

 with fleshy ones ; the first come out of their integu- 

 ments as the French-bean, the second continue in them, 

 and remain underground, such as the Pea, Vetch, Horse- 

 chestnut, &c. As most monocotyledons have the coty- 

 ledon fleshy, it is conformable to analogy that it should 

 be subterranean, which in reality is the case. 



A curious consequence which results from the nature 

 of the two kinds of cotyledons which I have mentioned, 

 is, that the fleshy ones alone are those which man makes 

 use of for food ; he takes for his own use the deposit of 

 nourishment which the mother-plant had prepared for 

 its offspring, in the same manner as in the eggs of birds : 

 it is thus that the seeds of the Leguminosa? with fleshy 

 cotyledons, such as Beans, Peas, Lentils, Cajanus, &c. 

 serve for the food of man, whilst those with foliaceous 

 ones are useless or dangerous. There are no apparent 

 exceptions to this rule but in albuminous seeds : it is 

 then the albumen, which is itself a deposit of nourish- 

 ment, that man makes use of; thus Buckwheat (Poly- 

 gonum) is edible on account of its farinaceous albumen ; 

 the Gramineae have at the same time a fleshy cotyledon 

 and farinaceous albumen, a double circumstance which 

 contributes to place them in the first rank among nutri- 

 tive seeds. 



The forms of foliaceous cotyledons are as variable as 



VOL. II. P 



