160 CRUCIFER.&. 



Etymology. Name from hpajin, acrid; in allusion to the pungent taste. 



Geographical Distribution and Division. A genus of 70 or 80 de- 

 scribed species, the greater part natives of the colder, and especially of the 

 arctic and alpine, regions of the northern hemisphere. There are 22 South 

 American species, of which three belong to Patagonia and the Falkland Isl- 

 ands, and the rest to the Andes. The species (of which there are very few 

 in the United States) are grouped under several sections, and divided by De 

 Candolle into two genera, namely, — 



§ 1. Draba, DC. — Petals entire or merely emarginate. Silicle ellipti- 

 cal, oblong, or linear. 



§2. Erophiljj, .D C. — Petals 2-cleft. Silicle oval or elliptical. 



PLATE 68. Draba arabisans, Michx. ; — specimen in fruit, of the nat- 

 ural size, from St. Lawrence county, New York. 



1. A flower, enlarged. 



2. A sepal ; and 3, a petal, more enlarged. 



4. Stamens and pistil, enlarged. 



5. A silicle, enlarged. 



6. Portion of the replum, with the seeds, more enlarged. 



7. Magnified seed, divided, to show the accumbent cotyledons. 

 PLATE 69. Draba (Erophila) vern t a, Linn.; — of the natural size. 



1. A magnified flower. 



2. A sepal ; and 3, a petal, more magnified. 



4. A stamen, equally magnified. 



5. A magnified silicle, transversely divided. 



6. The replum with the seeds, more magnified. 



7. Tissue from the partition, highly magnified. 



8. A magnified seed, divided, showing the accumbent cotyledons. 



