Chap. V] 



THE SOIL 



93 



wedge-shaped at the base and by having more delicate, more herbaceous, dull, 

 deciduous leaves. 



Both forms must be considered as fully adapted to their subtratum, for they 

 flourish on it with the greatest vigour and abundance. Asplenium adulterinum 

 almost entirely suppresses the common A. Trichomanes on serpentine, whilst the 

 original form A. viride has been only exceptionally observed. The typical A. 

 Adiantum-nigrum seems completely absent 

 from serpentine. Kalmus, speaking of the 

 station of A. adulterinum and A. Trichomanes 

 near Einsiedel, says that the latter appears to 

 him to be quite a little people which is only 

 allowed on sufferance by its superior neigh- 

 bours and relatives ; and Milde makes the 

 following remarks about the same plant : 

 ' The first thing that struck me was the great 

 density of its growth, partly due to the large 

 number of plants, partly to the immense clumps 

 which the plant often formed. I have never 

 observed such vigorous growth in A. viride and 

 only very rarely in A. Trichomanes V 



6. CALAMINE. 



The action on plants of large quantities 

 of the slightly soluble zinc ore usually 

 known as calamine (zinc carbonate and 

 silicate) resembles that of serpentine in 

 so far as it also induces hereditary modi- 

 fication in some plants, in this case Viola 

 lutea and Thlaspi alpestre, the physio- 

 logical and oecological connexion of which 

 with the nature of their substratum has 

 as yet obtained no interpretation. The 

 plants thus modified grow on a zinc soil 

 in great numbers and luxuriance, and do 

 not overstep its limits. 



Fig. 53. Viola calaminaria. 

 natural size. 



Half 



The calamine violet, Viola calaminaria, Lej. 

 (V. lutea, var. multicaulis, Koch.) (Fig. 53), 



differs from other forms of Viola lutea by its rich ramification, its longer stem, 

 and its smaller corolla, which however varies somewhat in size. In the case 

 of Thlaspi calaminare, Lej. et Court, the petals are broader than those of the t}^pe 

 form, and are much longer than the sepals, while the filaments are shorter than the 

 sepals. The zinc in the soil has induced in the one form an increase, and in 

 the other form a decrease in the size of the corolla. 



1 Sadebeck, I, 11. 



