1905-1906.] Formation and Flora of a Shingle Island. 293 



was little more than a gravel bank, and the river flowed 

 between it and Eilean a Phortaire proper. Nowadays the two 

 are continuous, but there is a sudden drop of two feet from 

 the high western end of Eilean a Phortaire to the low eastern 

 beginning of the newer island. In flood-time the stream still 

 flows between the two. This western island is 200 yards 

 long by 70 wide ; and, like the other, it rises westwards (that 

 is, down-stream) to a height of six feet. A thick belt of trees 

 clothes the southern and western edges ; and on the northern 

 edge young trees are growing up fast. The central space is 

 open and pasture-like, but a good deal interrupted here and 

 there by trees. The island begins on the east as almost pure 

 shingle ; but as one goes west, scattered tufts of moss (Grimm ia 

 fascicularis) are seen on every tiny sand-drift, and at last the 

 ground is covered with luxuriant moss tufts, interspersed with 

 little sandy spaces. Among the moss are flat-growing plants 

 of grass, scabious, ragwort, and golden-rod ; but these are 

 mere rosettes, mostly without a flowering -stem, and are, I 

 suppose, all quite young. Still going eastwards, vegetation 

 quickly becomes continuous ; the moss now forms a thick 

 carpet, but is half hidden by tiny heather -plants (Calluna 

 Erica), then by quantities of golden-rod, scabious, grasses, and 

 tormentil. The soil is still very sandy, but darker in colour. 

 Under the trees vegetation is ranker, and we have meadow- 

 sweet, wood-sage, brambles, and dog's-mercury ; with golden- 

 rod and scabious still persisting. There is a little raspberry 

 and wood crane's-bill, lady fern and male fern, dog-violet and 

 speedwell (V. Chamaedrys). In one spot Eanunculus repens is 

 growing, and in another wild hyacinth. The trees are nearly 

 all alder, with a few sycamore, willow, and ash ; and one or 

 two birch, bird-cherry, rowan, and hazel. 



The moss on this island appears to play a very important 

 part, acting as pioneer for the other plants, by helping to 

 retain the sand and to form humus. We pulled up a good 

 many pieces to see whether the sand beneath was affected by 

 the moss ; and, as far as we could judge, the sand underneath 

 was becoming slightly finer and darker coloured. 



This western island has had cows pastured on it, and 

 hay has once been cut there ; but it has never been under 

 cultivation. 



