364 Dr. Hooker's Account of a 



With regard to pubescence, this species appears as liable to 

 variation as the following one is known to be. 



6. -D. hirta. 



A very few specimens of this plant exist in the collection, 

 and these belong to what I have considered as a fourth variety 

 of D. hirta in my account of the plants of Captain Parry's 

 second Voyage : as "1 — 3 pollicaris, foliis integerrimis, scapo 

 gracili aphyllo." 



Some or other of the numerous varieties of this species are 

 found in the alpine countries of the north of Europe and 

 America ; and if the plant be, as I suspect, the R. nivalis of 

 De Candolle, it is also a native of the mountains of Switzer- 

 land, Savoy and Dauphiny. 



7. D. muricella. 



This quite agrees with the species so denominated by Wah- 

 lenberg, in the nature of its pubescence : but two out of five 

 stalks are furnished with a leaf; whereas Wahlenberg defines 

 the D. muricella as having a " scapus semper nudus." I am 

 here more confirmed in an opinion, that I have elsewhere ex- 

 pressed, that this is but a densely pubescent variety of D. hirta. 

 The gerraens and silicules are stellato-pubescent. 



Whether a variety or a species, this plant exists on the alps 

 of Switzerland, as well as those of Lapland, Norway and Si- 

 beria. Dr.Richardsonfounditin Arctic America; Mr. Jame- 

 son on the west coast of Greenland, and Captain Parry in the 

 Strait of the Fury and Hecla. 



De Candolle has placed the D. muricella in his division of 

 the genus Chrysodraba ; whereas the inflorescence is con- 

 stantly white. Perhaps the D. tomentosa of that author might 

 safely be referred hither. 



8. D. in- 



