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 alhed 

 with A. Adiantum-nigrum and A. viride.^ 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 - 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 



Hutchinsia alpina 

 Thlaspi rotundifolium 

 Anemone alpina 

 J uncus monanthos 

 Primula Auricula 

 Ranunculus alpestris 



Not Calcicolous 



Hutchinsia brevicaulis 

 Thlaspi cepeaefolium 

 Anemone sulphurea 

 J uncus trifidus 

 Primula villosa 

 Ranunculus crenatus 



Dolomite 



Androsace Hausmanni 

 Asplenium Seelosii 

 Woodsia glabella 



Not Dolomite '^ 



Androsace glacialis 

 Asplenium septentrionale 

 Woodsia hyperborea.^ 



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.^ Observations 

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

 Kerner observed in parallel forms the following distinctions : 



Calcicolous 



Plants more strongly and densely 

 clothed with hairs ; often clothed 

 with a white or grey felt. 



Leaves often bluish green. 



Leaves more divided and more 

 deeply so. 



If the leaves be entire 



Corolla larger 



Flowers mostly with duller surface 

 but lighter hue. 



Not Calcicolous 



Hairs glandular. 



Leaves grass-green. 



Then the leaves not uncommonly 

 glandular-serrate. 



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

 ' Kerner, 1869. " Kerner, 18636. 



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

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



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



