36 Mr. Brown, on the ProteacecB of Jussieu. 



me to suppose that it is the organ 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 chU' 

 laza and continued to adhere to it: nothing has hitherto oc- 

 curred to invaHdate this opinion, which is here however hazarded 

 merely as a conjecture, requiring for its confirmation more nu- 

 merous 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 Proteaceae : nor are 

 the few exceptions with which I am at present acquainted of so 

 decisive a nature as to invalidate this character of the order ; for 

 they occur onl}' in some species of Persoonia, where the semi- 

 fluid remains of this substance are observable between the coty- 

 ledons ; 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 maybe neces- 

 sary from the whole of their organization to refer to this family. 



The RADicuLA pointing towards the base of the fruit in all 

 Proteaceae is a circumstance of the greatest importance in di- 

 stinguishing the order from the most nearly related tribes ; and 

 its constancy is more remarkable, as it is not accompanied by 

 the usual position or even uniformity in the situation of the 

 e]|^ernal umbilicus, 



If 



