The Flora ol' Disko Island and Adjacent Coast of West Greenland. 129 



may be urged, that 1) this character marks all f ruiting specimens seen 

 from Greenland, also those growing 4 degrees of latitude south of the 

 northern limit of L. groenlandicum ; 2) that I did not fmd it on any 

 specimen of L. palustre from unfavourable habitats; and 3) that speci- 

 mens of L. groenlandicum, whose genuineness was proved by other 

 characters, growing with L. deciimbens near the northern limit of L. 

 groenlandicum showed no tendencies to such an abrupt booking of the 

 peduncles. 



The morphologically basal part of the capsule-valves of L. palustre 

 are distinctly outwardly bent. In L. groenlandicum no such thing is 

 seen, the outer surface of the valves being symmetricai. In L. decumbens 

 the basal parts of the valves are often outwardly curved, but only very 

 slightly or indistinctly. 



The distinguishing characters of the 3 species as found 

 by various authors may be summarized as given in the following page. 



The Geographical Distribution. (By M. P. P.) 



The main points of the distribution of the Let/wm-species in Green- 

 land was already known to Jens Vahl, and have since been elucidated 

 by Lange and Rosenvinge and I have not much to add. 



I 226. Ledum decumbens (Ait.) E. & M. P. Porsild 



nov. comb. 



On heath, often on very dry forms of heath, as for instance oa 

 tertiary sands. Sometimes in not too moist mossy bogs. 



Disko: Common in the gneissic part. Also common in the sandy area on the 

 south coast, here almost exclusively forming the heath. Ascending to at least 700 m. 

 On basaltic ground covered by old and dense vegetation often common, but not 

 occurring in fresh morainic soil. Besides there are, however, rather wide areas of 

 the island especially on its northern and western part, where one may walk for miles 

 without seeing the plant. (P.). 



Hare 0: Occurring, but scarce (P.). 



Mainland: On the basal tic part of Nugssuaq peninsula sporadic like on Disko. 

 On the gneissic part from Torssukåtak soutwards, however, continually distribu- 

 tcd and common everywhere. In the southern part of the area commoner on the 

 outer coast and on the hills, whilst the more favourable localities in the Iowland are 

 mostly occupied by the following species. , 



According to Rosenvinge very rare south of 64", but seen by him 

 down to 61°. In the Herb. Haun. we saw no specimens south of 63°. 

 The northern limit in West Greenland is still unknown, but is to be 

 found somewhere north of 74°. Hence a northern type. 



LVIII. 9 



