374 THE ALCE OF GUERNSEY. 



At first I imagined that this was due to the fact that on 

 a small wind-swept island like this all marshes and ditches 

 must to a certain extent he impregnated with salt, and also 

 that the likeliest spots, especially at the north and north-west, 

 are situated on land that was until comparatively recent times 

 covered by the sea. But on further reflection, and bringing 

 to bear on the point an experience of several years in this 

 same field of work in the Land's End district of Cornwall — 

 itself almost an island — I incline to think the scarceness of 

 Fresh Water Alga3 in general, and more particularly of 

 Desmids, is due to another cause, viz. : the natural drainage 

 of highly-manured land, and the pollution of cattle. And this 

 view is favoured by the generally poor and unhealthy condition 

 and feeble growth for the most part of such species as I am 

 about to record. 



Be this as it may, however, the collector of Fresh Water 

 Algae will not find here a very productive hunting ground. 

 The most attractive spot, the most promising piece of ground 

 in the whole island — Grande Mare, the home of so many rare 

 flowering plants — is extremely poor in the matter of alga?. 

 Very few species occur in quantity, and even these compara- 

 tively common ones are seldom found in a state of fructification. 

 Many filamentous fresh water algae are perplexingly alike in a 

 barren state, and can only be identified with certainty after an 

 examination of the fruit ; hence I have been obliged to omit 

 from my list a considerable number which I could not name with 

 confidence, although recognising them as new. I have in mind 

 a very similar piece of boggy ground in Cornwall, about the 

 size of Grande Mare, and equally close to the sea, which was 

 amazingly rich in algae. A single gathering of Desmids once 

 yielded me no less than sixty-eight species ; and in all I have 

 collected in that same marsh considerably over one hundred 

 different forms ; whereas repeated gatherings from Grande 

 Mare, selected and examined with great care, have scarcely 

 produced half-a-dozen Desmids, and these mostly in poor 

 condition. 



I think it well to record my experience on this point, 

 because it is certainly as instructive to learn that a given 

 district is deficient in some branches of its fauna and flora, as 

 it is to know that it is more than usually productive in others. 

 Guernsey is as I have said exceedingly rich in seaweeds, but 

 that is no reason at all why it should be relatively so poor in 

 the fresh water algae. If these remarks should induce other 

 students to carry on investigations with a view to discover the 

 true cause my aim will have been fully attained. 



