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Cruciferous plants, the generic differences of which are diffi- 
cult to seize.perhaps beyond all others, was made by the 
gentleman to whom we are obliged for our article; and 
that the soundness of those:characters: has never yet been 
questioned, even by theorists. 
In illustration of these remarks, we cannot do better 
than transcribe the words of M. Decandolle, who (Regn. veg. 
144). observes, that “ A methodical arrangement of cru- 
“ ciferous plants is, on account of the close affinity of 
“the genera, both difficult and ambiguous. The division 
“of the order into Stliquose and Siliculose, which. was 
“ first established by Ray, and afterwards adopted by Lin- 
““ neeus and most other botanists, although it has the ap- 
“ pearance of being convenient, is not only occasionally 
“ uncertain, but has the great defect of not according with 
“ the anatomical structure and natural affinities of the ge- 
“nera. In the first place, the silique and the silicule differ 
“from each other only in length; and every degree of 
“ length is to be found, not only in allied genera, but even 
** among species of one and the same genus; so that Drasa, 
“ for instance, Nasturtium, HEniopHita, Erysimum, ARABis, 
“ Srevents, Eruca, and others, even after the most rigid 
“ examination,necessarily include examples of Siliquosce and 
“ Siliculose mingled together. Secondly, there are certain 
“ cruciferous genera, such as Rapisrrum, Caxite, Cramer, 
* &c. the fruit of which being neither silique nor silicule, is 
“so anomalous as to have received a distinct appellation 
“ from some modern writers, and to have been termed nu- 
_ “camentaceous. In the third place, the length of the 
“¢ style is not always in an inverse ratio to the length of the 
‘pod, but has been observed to be long in many Siliquosc, 
“and very short or nearly obsolete in other Siliculosce. 
* Characters, however, of a more constant and important 
*‘ description, having been remarked by Geertner, were suc- 
“ cessfully introduced as the basis of the generic characters 
“ of the order by Mr. Robert Brown. These characters are 
“ deduced from the internal structure of the seed, and more 
“ especially from the relative position of the radicle and 
* cotyledons; and although it must be confessed, that 
“ prejudices with regard to the association of species, which 
“ have become almost sanctified in our minds by habit, are 
“in some cases attacked, the genera founded upon those’ 
*< principles are not only much better defined, but far more 
