260 



PHYTONOMY. 



these bodies into the stem. But, without entirely denying 

 this connection, which, however, cannot be shewn in all cases, 

 there is a complete objection to this account in the structure 

 of the vitellus, and in the composition of its juices. In the 

 vitellus those small granular bodies are wanting, which are 

 deposited by the mucilage and albumen, and which we ob- 

 serve in the cotyledons ; while, on the other hand, it contains 

 in the Scitamineae peculiar ingredients, namely, volatile oil 

 and aromatic matter. Other authors, as Claud Richard 

 (Analys. du Fruit, p. 27. ; Ann. de Mus.) consider the 

 sheath of the first leaves (called hlastus) as the cotyledon, 

 though with still less propriety, because these are no way dis- 

 tinguished from the leaves that come after them. In fact, 

 the Grasses and Cyperoidae have no proper cotyledon. As 

 little have the Aroidae, in which the embryon for the most part 

 lies, with the end of its root thickened, in the middle of the 

 albuminous substance : the Naiadae also are destitute of this 

 structure. In the Junceae and Palmae, a tubercle proceeds 

 during germination out of the first horizontal shoot, and 

 from this tubercle the plant and radicle are first evolved, 

 (385.) Intermediate forms, as Zamia and Cycas, have a 

 distinctly divided cotyledonous body, which also shews itself 

 in the Pipereae. The same organ is found in the trees of the 

 Pine tribe, which have been falsely ranked among the po- 

 lycotyledonous plants ; because their first leaves are difierent 

 from those that follow in number and form. But, notwith- 

 standing this, they are still leaves, and not cotyledons. In 

 the Sarmentaceae and Coronariae, the embryon is unevolved, 

 and stands either in the centre of the albuminous substance 

 or surrounds it. It has sometimes a thickened cotyledo- 

 nous end {Hemerocallis^ Hamaiithus) ; in the Gloriosa it is 

 even divided into cotyledons. In the Hydrocharidae the 

 thickened end of the embryon seems to hold the place of the 

 albuminous substance ; and in the Orchideae, where, from the 

 fineness of the seed no parts can be distinguished, the young 

 plants unfold themselves in the same manner as Ferns, that 

 is to say, first a soft, cellular, lobed body, and after it a tu- 

 bercle arises, out of which the young plant springs. 



