CHAP, xv NUTRIMENT IN SOIL 57 



On serpertine, a silicate of magnesium, there grow two species of 

 Asplenium, A. Serpentini and A. adulterinum, which are closely allied 

 with A. Adiantum-nigrum and A. viride. 1 These new forms of Asplenium 

 have not yet become fixed, but in other cases fixation has probably taken 

 place, so that only very prolonged action could reform them, if indeed 

 it could do so at all. 



According to Kerner's 2 researches in the Alps, there exists a wide 

 difference between parallel species occupying limeless slate and limestone 

 mountains ; such parallel species, or, better perhaps, races, are the 

 following : 



Calcicolous Not Calcicolous 



Hutchinsia alpina Hutchinsia brevicaulis 



Thlaspi rotundifolium Thlaspi cepeaefolium 



Anemone alpina Anemone sulphurea 



Juncus monanthos Juncus trifidus 



Primula Auricula Primula villosa 



Ranunculus alpestris Ranunculus crenatus 



Dolomite Not Dolomite 3 



Androsace Hausmanni Androsace glacialis 



Asplenium Seelosii Asplenium septentrionale 



Woodsia glabella Woodsia hyperborea. 4 



Since such species as replace each other on different soils are certainly 

 derived from one parent species, it becomes of interest to ascertain wherein 

 they differ from each other, because the effects of the soil will presumably 

 be revealed. The first experimental investigations on the action of 

 calcium were, according to Schimper, made by Bonnier. 5 Observations 

 in the open air were conducted by Fliche and Grandeau, and others. 6 

 Kerner observed in parallel forms the following distinctions : 



Calcicolous Not Calcicolous 



Plants more strongly and densely Hairs glandular. 



clothed with hairs ; often clothed 



with a white or grey felt. 



Leaves often bluish green. Leaves grass-green. 



Leaves more divided and more 



deeply so. 

 If the leaves be entire Then the leaves not uncommonly 



glandular-serrate. 

 Corolla larger 

 Flowers mostly with duller surface 



but lighter hue. 



1 See Schimper, 1898 (1903, p. 93) ; also Pfeffer, 1897-1904. 

 1 Kerner, 1869. * Kerner, 18636. 



4 Blytt doubts if the Norwegian Woodsia glabella be the dolomite form of 

 W. hyperborea ; it occurs not only on dolomite, but also on slate. 



6 Bonnier, 1894. ' See Schimper, 1898 (1903, p. 95). 



