The Scottish Naturalist. 



299 



Bromus giganteus L. j Brachypodium sylvaticum R. & S. ; 

 Agropyron caninum Beauv. and A. repens Beauv. 



Asplenium Trichomanes L. ; Athyrium Filix-foemina Roth. ; 

 Cystopteris fragilis Bernh. and Lastrea Filix-mas Presl. This is a 

 smaller number of ferns than might have been expected. 



Equisetum arvense L. 



This list, it may be mentioned, includes more than one- 

 fourth of the total number of species of Perthshire phanero- 

 gams. Whilst of interest as demonstrating how, under favour- 

 able conditions, a large number of species can grow spon- 

 taneously in a limited area, it also suggests other lessons. It 

 illustrates, for example, the agency of a rapid river in the distribu- 

 tion of the flora of a district ; and, while showing what plants are 

 most liable to be transmitted by water, it affords negative evidence 

 as to the unsusceptibility of others to that mode of conveyance. 

 Furthermore, a study of the plants which successively occupy a 

 growing shingle will convey much instruction as to the conditions 

 •of habitat necessary to many species and their consequent dis- 

 tribution. 



VAKIETY OF C ABD AMINE AMAEA L. 



By F. Buchanan White, M.D., F.L.S. 



A LTHOUGH Cardamine amara is a common plant in lowland 

 jTx. Perthshire, I have not met with any variation in its charac- 

 ters till quite recently. When botanising on the banks of the May, 

 ■a tributary of the River Earn, I came across a large bed, every 

 plant in which had flowers of a purplish lilac colour, giving the 

 species such a different aspect from usual, that at the first glance 

 I did not recognise it as Cardamine amara. While all the British 

 books I have consulted describe the flowers as white, in the Flore 

 -de France (Grenier and Godron), they are said to be "rarement 

 violettes" so that a colour variation seems not to be unknown. 

 But in my plant the colour is not that of Viola odorata (which 

 Grenier and Godron call " Violette"),but rather that of peach 

 blossom. Apart from the colour, there is not much difference be- 

 tween the variety and the type. The leaflets of the upper leaves 



