ON THE PR0TEACE.E OF JUSSIEU. 23 



chalaza, which, whatever may be the point of insertion 

 of the seed, is always situated at its upper extremity ; and 

 I have not been able to observe any fasciculus of vessels 

 connecting it with the umbilicus in cases where this latter 

 is placed in a different part of the seed. 



I am not aware of any function being ascribed to the 

 chalaza of seeds, except the nutrition of their proper 

 membrane : but it appears to me too remarkable a part to 

 be destined for this purpose only ; and some observations 

 I have made induce me to suppose that it is the organ [36 

 secreting the liquor amnios. This opinion I was first led 

 to form by observing in some species of Persoonia, in which 

 the inspissated remains of this fluid are visible in the ripe 

 fruit, that it evidently originated in the chalaza and con- 

 tinued to adhere to it : nothing has hitherto occurred to 

 invalidate this opinion, which is here however hazarded 

 merely as a conjecture, requiring for its confirmation more 

 numerous and decisive facts than I can at present adduce. 



That the albumen of seeds is merely that condensed 

 portion of the liquor amnios which remains unabsorbed by 

 the embryo, seems to me very satisfactorily established ; 

 and as this fluid is in the early stage never wanting, all 

 seeds may in one sense be said to have albumen : but 

 while in some tribes this unabsorbed part in the ripe seed 

 many times exceeds the size of the embryo, so there are 

 others in which not a vestige of it remains ; and such has 

 hitherto been supposed to be the case with Proteacege : 

 nor are the few exceptions with which I am at present 

 acquainted of so decisive a nature as to invalidate this cha- 

 racter of the order ; for they occur only in some species of 

 Persoonia, where the semi-fluid remains of this substance 

 are observable between the cotyledons ; and in Bellendena, 

 in which it continues to form a thin fleshy coat on the 

 inner surface of the proper membrane of the seed. From 

 such instances, however, we may expect to find plants with 

 a more copious albumen, which nevertheless it may be 

 necessary from the whole of their organisation to refer to 

 this family. 



The radicula pointing towards the base of the fruit in 



