Dr. Smith's Inquiry into the Structure of Seeds. 207 



have " a single-lobed corculum" have been shown by Mr. Salis- 

 bury, in the 8th volume of our Transactions, the only person I 

 believe who has well examined their germination, to have in fact 

 an Albumen, but no Cotyledon at all. Nor does such ambi- 

 guity or uncertainty belong to this family alone. Many plants 

 are presumed to be monocotyledonous, chiefly because they 

 grow in the water ; and it is much to be regretted that this fun- 

 damental principle of all natural systems should in many cases 

 be so ill-established, and very often so extremely difficult to de- 

 tect or to determine ; which happens in general where its help is 

 most wanted, as I shall presently endeavour to show; but I 

 must first speak of the more immediate object of the present 

 essay. 



Gaertner asserts the Vitellus of seeds to be " distinct from the 

 " Cotydelons as well as from the Albumen, and, for the most 

 " part, situated between the latter and the Embryo." He con- 

 siders as its principal diagnostics the 3 following characters : 

 " 1st, that it is most closely connected with the Embryo, so as 

 " not to be separable from it without injury to its own substance: 

 " 2dly, that notwithstanding this intimate connection, it never 

 " rises out of the integuments of the seed, as the Cotyledons 

 " usually do, in germination, so as to become a seminal leaf, 

 " but, rather like the Albumen, its whole substance is destroyed' 

 " by the seedling plant, and converted into its own nourishment: 

 " and 3dly, that if the Albumen be likewise present, the Vitcl- 

 " ins is always situated betwixt that and the Embryo, in such a 

 " manner, however, that it may be separated from the Albumen 

 " with great ease and without injury." For which reasons this 

 able writer considers the organ in question as " allied on the one 

 " hand to the Albumen, on the other to the Cotyledons," but 

 truly distinct in nature from both. He proceeds to observe that 



"it 



