350 THE JOURNAL OF BOTANY 



Of the specimens contained in herbaria in Bangor two were 

 completely described. One collected by Dr. J. Lloyd Williams 

 from Garn Dolbenmaen in the month of June was of the heath 

 type, but with a very strong rosette of over twenty branches, the 

 portion below the rosette being thickened and rhizomic in appear- 

 ance, procumbent, and tapering. Another obtained by the author 

 from the Goyt Valley, Buxton, was of the marsh type, with 

 elongated lower portion of succulent stem and few branches. It 

 was, however, taken in August. 



The above observations have led to the transplanting of these 

 forms into different conditions to test their stability. 



The variability of any species might be roughly estimated as 

 proportional to the number of varieties assigned to it by a syste- 

 matist of the " splitter " type ; that of a genus would, similarly, 

 be proportional to the number of species allotted. 



The view is now commonly held that, given a sufficient know- 

 ledge of the conditions to which a plastic genus is subjected, a 

 series of species and varieties might be postulated and described 

 correlated with these conditions. It appears, however, that all 

 combinations of the different affective factors, whether edaphic or 

 epidaphic, are not stable, except, perhaps, momentarily; that is to 

 say, a complete and continuous series of such factors acting on a 

 given species could not be compiled, even if reliable data from all 

 parts of the world were available. 



The interaction of climatic and edaphic factors does, however, 

 give rise to definite "adaptations" in the genus and "accommo- 

 dations " in the species (see Massart's Le Bole de V Experimenta- 

 tion en Geographie Botanique, 1912). These maybe considered as 

 the response to definite " resultants " between the affective 

 factors. When these resultants are widely divergent in quantita- 

 tive and directive action, specific differences are caused and may 

 become fixed and hereditary. When the divergence is slight, 

 differences of varietal range are induced, some of which may be 

 stable and eventually become fixed ; others remain modifiable, 

 giving rise to local variations. 



The plant may be said in Massart's phrase to " adapt " itself 

 to widely divergent resultants, and to "accommodate" itself to 

 those of lesser divergence. 



JUNCUS BALTICUS Willd. IN ENGLAND. 

 By E. S. Adamson, M.A., B.Sc. 



In May, 1913, I discovered Juncus balticus growing in 

 moderate quantity in a damp hollow on the sandhills, locally 

 known as a " slack," near Southport, Lancashire. The plant 

 occurs in some hollows that are permanently damp but not really 

 swampy. It occurs in association with such plants as Sagina 

 nodosa var. monilifera, Pamassia palustris var. condensata, 

 Anagallis tenella, Erythrcea littoralis, Blackstonea perfoliata, 



