190 VEGETABLE ORGANOGRAPHY. 



The general form of the albumen is moulded upon 

 the inner cavity of the endopleura, and is modified by 

 that of the embryo. In general, it is all in one mass ; 

 but there are some genera of the Rubiaceae, such as 

 Rutidea and Grumilea, where it is presented under the 

 appearance of little portions detached from one another. 

 It presents in some plants, and especially in all the 

 Anonaceae, a character which is very remarkable, viz. — 

 the endopleura is wrinkled or prolonged into projecting 

 laminae, so that when the albumen is cut lengthways, it 

 seems furnished upon its margins with little transverse 

 lamellae, a very remarkable character which Mr. Robert 

 Brown has met with in the anomalous genus Eupomatia, 

 which he discovered in New Holland. 



The position of the albumen is always in the empty 

 space left by the embryo, which is in general more or 

 less central, and then the albumen surrounds every part 

 of it ; the embryo is sometimes lateral, or situated at the 

 base near the chalaza, and then the albumen occupies 

 the rest of the cavity, as in Portulaca, the Marvel of 

 Peru, &c. : lastly, when the embryo is peripherical, then 

 the albumen is found in the centre, as, for example, in 

 several Polygoneae and Chenopodeaa. There are seeds 

 among the Malvaceae and Bombaceae, in which the albu- 

 men is reduced to a small farinaceous deposit, lying 

 between the cotyledons. 



The use of the albumen has not yet been perfectly 

 studied ; it is evident that the amnios, especially when it 

 is absorbed, must serve to nourish the embryo, and that 

 the albumen must serve to nourish the young plant at 

 the period of germination. We see, in fact, that most, 

 if not all albumens are transformed at this period, by the 

 addition of the water which they absorb, into an emulsion- 

 like matter, which is absorbed by the embryo, and serves 

 to develop it ; but the details of this phenomenon have 



