North American Plants. 91 



With the latter botanist originated the terms accumbent and 

 incumbent now so generally employed, although neither he nor 

 Schkuhr used these characters in classifying the Cruciferae. The 

 form and direction of the Cotyledons were first introduced into 

 the generic characters by R. Brown, in the second edition of 

 the Hortus Kewensis, (vol. iv. 1812) but not extensively, as 

 this was not a suitable work in which to develope his views. 

 De Candolle, in his Systema (1S21), and in his Memoire sur 

 les Cruciferes (1821), as well as in his Prodromus, (vol. i. 

 1S24), adopted Brown's idea of the importance of the embryo 

 in this family, and made it the basis of his classification, but 

 carried it further, perhaps, than the great English botanist in- 

 tended. It must be confessed that there are a few instances in 

 which the modifications of the embryo are not even of generic 

 importance, as in Hutchinsia alpina and petrcea, noticed by 

 Brown, the cotyledons being accumbent in one species and in- 

 cumbent in the other. In Lepklium Yirginicum, as shown in 

 Schkuhr's figure, {Handb.* 2, t. 180,) and in Hooker's Flora 

 Boreali-Americana, the cotyledons are accumbent, while in the 

 rest of the genus they are incumbent. Capsella Bursa pastoris, 

 which has incumbent cotyledons, is now generally admitted to 

 be distinct from Thlaspi. In Cakile, as the genus is limited by 

 De Candolle, there are species in which the cotyledons are 

 not accumbent. In the figure of C. cequalis, as given by De- 

 lessert in his Icones Selectee, f (the drawings of which were exe- 

 cuted by Turpin,) the cotyledons are represented as mcumh ///, 

 a circumstance which appears to have escaped the notice of 

 De Candolle, although he quotes the figure in his Prodro- 

 mus.^: In C. maritime/,, C. A. Meyer§ states that lie found the 

 seed in the lower cell of the silique, having the nidicle oblique 

 or tangent to the limb of the cotyledon, while in the upper cell 



* There called L. Iberis, but not the plant of Linnaeus thus named. 



f 2, t. 57. 



X 1, p. 186. 



§ Erntm. pi Cauc. p. 186. (1831.) 



