The Jussieuean, or Natural, System of Plants, 239 



north latitude may be considered the equatorial line of Cru- 

 cifer£B, about half being found on one side of it, and half on 

 the other. Their station is very variable; many inhabit 

 open sandy places, some form the vegetation about the limits 

 of the perpetual snows of lofty mountains, and many follow 

 the footsteps of man through all parts of the world. 



The useful qualities of the turnip, the radish, the rape, and 

 the cabbage, and its multiform varieties, are all well known. 

 The greater part of the order consists of plants possessing 

 high antiscorbutic powers. These appear to depend upon a 

 certain acrid volatile oily principle, the chemical nature of 

 which is imperfectly known. It is particularly abundant in 

 the seeds of mustard, the roots of horseradish, and the 

 leaves of iepidium latifolium, which last exercise a violent 

 influence upon the organs of digestion. The same sort of 

 acrimony, but in less degree, is found in the herbage of the 

 scurvygrass and the roots of the radish, which act much 

 more mildly when taken inwardly ; thus, when any cruciferous 

 plants are found to be eatable, either from culture or other 

 circumstances, it is to be understood to depend upon a reduc- 

 tion of this acrid principle. The exciting powers of this prin- 

 ciple are what render the horseradish, the scurvygrass, and 

 others, so remarkably useful as antiscorbutics. Plants of this 

 order are also believed to possess diuretic and diaphoretic pro- 

 perties. It is to be remarked that Cruciferae are always eat- 

 able when their texture is succulent and watery, as in the roots 

 of the radish and turnip, and in the leaves of the ciabbage tribe. 

 A further diminution of the acrid principle is produced by 

 blanching. Cruciferae are said to possess a greater share of 

 azote than any other tribe of plants ; as is apparent in their 

 fetid smell when fermented. The embryos of all the order 

 abound in oil, whence many species are employed with much 

 advantage for expressing, either for the table or for feeding 

 lamps. Some of the species are extremely beautiful and fra- 

 grant, as the stocks, the gillyflowers, the hesperides, the candy- 

 tufts, and many others. The hutchinsias, drabas, cardamines, 

 &c., are among the most interesting of alpine plants. 



Suborder I. PLEURORHrZJE, o = 



Tribe l. -^rabi'de^i:. 



Mathiola R. Br. Barbar^a R. Br. Macropodium R, Br, 



Cheiranthus L, Braya Stern. Cardamine L. 



iVasturtium R. Br. Turritis Dil, Pteroneuron Dec, 



Leptocarpae'a Dec, ^'rabis L. Dentaria L, 

 Notoceras R, Br, Parrya R. Br. 



R 4 



