CI. 13.] crucifer^:. 139 



axillary, mostly terminal, racemose, or corymbose, 

 sometimes panicled." 



This Order, constituting Linnaeus's 15th Class, is 

 so natural in itself, that we can scarely say whether 

 any real affinity exists between it and any other. 

 Hi/pecoum, in the last, betrays a slight resemblance, 

 rather than a relationship, to this; as Cleome does in 

 the following- • but this last genus is incorrectly 

 referred by Linnaeus to his Tctr adynamia, according 

 to any rule that I can discover. 



The Genera of Cruciferaz, in which Jussieu follows 

 Linnasus, are among the least satisfactory in either 

 of their systems. Mr. Brown, in Ait. Hort. Kew., 

 ed. 2. v. 4, has greatly improved them, taking into 

 account the position and direction of their Cotyledons, 

 whether spiral, doubled, or flat ; incumbent, folded 

 together upon the Embryo, or accumbent, folded con- 

 trariwise, their edges meeting the Embryo. The num- 

 ber of Seeds also lends occasional assistance, in the 

 Siliculosa at least. His principles are adopted by 

 DeCandolle, and in Engl. Fl. v. 3. 



In some few instances, 2, or even 4, of the Sta- 

 mens are wanting. 



Crambe, Coronopus*, Peltaria, whose Pouch does 

 not burst, Isatis, Vet/a, Teesdalia Br., fig. 25-27, 

 Iberh, Thlaspi, fig. 23, 24, Lepidium, Farsetia, and 

 Lunaria, are among the best genera in Tctradynamia 

 Siliculosa; as are 



Arabis, Brassica, Sinapk, and Raphanm, in T. Si- 



I* Sfndnu-a. DeCafld. Syst.*V..-2. 521. E'nfel. FI. v. 3; 178. 



