208 VEGETABLE ORGANOGRAPHY. 



green colour; they then take the exclusive name of 

 Seminal Leaves. 



All those which have no stomata, remain in a fleshy 

 or farinaceous state, and do not become green; these are 

 usually only called fleshy cotyledons. 



Foliaceous ones are very frequent among Dicotyle- 

 dons, and are hardly ever found in Monocotyledons, but 

 they exist in Ferns. Fleshy ones are common in Mono- 

 cotyledons ; they are also met with among the Dicoty- 

 ledons in the tribes Phaseoleae, Viciae, &c. of the Legu- 

 minosae, in Hippocastaneas, Trapa, the Chestnut, &c. ; 

 foliaceous cotyledons are, in general, more frequent in 

 albuminous Dicotyledons ; and fleshy ones in those which 

 are exalbuminous ; the reverse would seem to occur in 

 Monocotyledons. 



Foliaceous cotyledons being furnished with stomata, 

 can, from the moment they are exposed to the air, 

 elaborate the sap which is transmitted to them by the 

 radicle, and, consequently, it is not necessary that they 

 should be provided with a store of nutriment prepared 

 beforehand for the young plant ; fleshy ones, having no 

 stomata, cannot elaborate the sap, and there would be 

 no action if they were not filled with a quantity of fecula 

 or mucilage, which, diluted by the water absorbed by the 

 radicle, is thus transformed into nourishment. We may 

 say, then, that the cotyledons nourish the young plant, 

 when they are foliaceous by elaborating the sap in the 

 same manner as leaves, and when they are fleshy by fur- 

 nishing nutriment prepared beforehand, as in the albu- 

 men or tubercules ; whence it results that every organ 

 which has no stomata, and is not fleshy or filled with 

 fecula, is not a cotyledon, an important character which, 

 in certain doubtful cases, elucidates the nature of 

 organs ; for example, it has enabled me to deter- 



