316 DR. HOOKER ON THE DISTRIBUTION OF ARCTIC PLANTS. 



Of these, Mr. Ball is disposed to unite 1 and 2, and also 4, 5, and 6, making but three 

 sjiecies in the above group, but distinguishing six sufficiently weU-marked forms. 



D. muricella is in Europe confined to Scandinavia ; neither D. hirta nor rupestris are 

 found in the Alps. 



Deaba alpina, L. Regarding the numerous plants here brought together I have the 

 following notes : — 



B. algida, Ad., according to specimens from Ledebour and Bunge, differs in no respect 

 from D. alpina. 



B. pilosa, DC, is reduced to a synonym of D. aUjkla by Ledebour. I have no authentic 

 specimens of it. 



B. aspera, Adams, is placed by Ledebour in the section Aizoopjsis, the species of which 

 are eminently southern and oriental ; that author, however, had not seen the plant, and 

 overlooks the fact of the distinguishing characters given by Adams being those of B. 

 alpina. 



B. Adamsii, Led. {lasiocarpa, Adams), is described as differing fromZ). alpina in the 

 pu.bescent pods, stellate hairs of leaves and scape, and smaU flowers ; but the pods of 

 alp)ina are glabrous or pilose, and the other characters equally inconstant. 



B. glacialis, Adams. Of this there are five varieties described in ' Elora Boreali- Ameri- 

 cana.' It should be distinguished by the costa prominent in the under surface of the 

 leaf; but amongst a vast suite of specimens thus named I find the prominence of the 

 costa to depend on the development of the leaf, and no characters that would serve to 

 include those so distinguished, even as a permanent variety of alpina, L. Durand (Kane's 

 Voy.) keeps glacialis j3 distinct. 



B. pauciflora, Br. This was proposed by Brown as a doubtful species from Melville 

 Island ; and I find, amongst starved specimens of B. alpina from that island, some that 

 may be the plant that Brown alkided to. 



B. microjjetala, Hook. This appears to me, without doubt, to be a starved form of 

 alpina. It occurs only in very high northern latitudes, amongst the polar islands. 

 Durand (Kane's Voy.) makes of it B. alpina, var. micropetala. 



B. trichella, Pr. Mr. Ball considers this to be probably a form of aljnna. 

 DiiABA androsacea, Wahl. {Lajjponica, DC. an Willd. ?). This is a white-flowered 

 species presenting as many puzzling forms as B. alpina, besides appearing to pass by 

 insensible grades into hirta, rupestris, and muricella. Nor is it always possiljle to 

 distinguish androsacea from alpAna in a dried state, nor when the flowers of the former 

 are bleached or vary to whitish, which they occasionally do both in the arctic circle and 

 Himalaya. Of this plant B. TFaUenbergii, Hart., and lactea, Adams, are now generally 

 acknowledged synonyms, as is B. nivalis, DC, non Lilj. 



B. crassifolia, Grab., has been referred by Mr. Ball (in Herb. Hook.) to lactea. Ad. 

 {Fladnitsensis, Wulf), and certainly rightly. The yellow-flowered plant figured in ' Flora 

 Danica ' is referable to alpina, L. 



B. Martinsiana, J. Gay. Of this species I know nothing accurately. 

 B. oligosperma, Hook., is not different, I think, from the specimens marked Fladnit- 

 zensis from the Alps and Altai, and, further, is certainly a small form of androsacea, with 



