1 905-1906.] Formation and Flora of a Shingle Island. 301 



phyllus, Mentha sylvestris,'^ and Polygonum cuspidatum.^ 

 All these plants were growing on the north-western fertile 

 part of the island ; ^ and in this same area are springing up 

 many bushes and young trees, chiefly along the northern 

 margin. We counted 55 willow, mostly Salix aurita(?), 17 

 alder, 16 wild rose, 12 bird -cherry, and 6 ash. Most of 

 these are quite tiny, but several of the willows and alders 

 are larger, the tallest being a ten-foot alder. The ashes are 

 all tiny, and do not look healthy. The sycamore, birch, beech, 

 oak, hazel, and red currant of our list are the merest seedlings 

 — one seedling of each kind. 



Over part of the island, where little else grew, Grimmia 

 fascicularis was flourishing.^ This was on a stretch of bare 

 shingle, and on an adjacent sandy corner that unites it with 

 the north-west overgrown area. But for this moss and 

 Plantago maritima, the large stretches of shingle on the 

 island are the merest barren wastes, with here and there 

 widely scattered roots of grasses, Centaurea nigra and Plantago 

 lanceolata ; and more locally, Lotus corniculatus, Tussilago 

 Farfara, Oxyria digyna, Kumex Acetosella, and Equisetum 

 sylvaticum. These last five plants tend to form colonies. 



Complete list of Shingle Island flora. — One of our special 

 aims was to ascertain where the island flora originally came 

 from ; and to this end we made a thorough search of the land 

 immediately adjoining — namely, the right river-bank, both 

 directly opposite the island and for some distance up-stream. 

 Lack of time prevented our studying Eilean a Phortaire so 

 thoroughly. The left river-bank we did not examine ; and, 

 judging from its position, it hardly affects the problem. The 

 following list gives the whole of the Shingle Island flora, as 

 far as we ascertained it, and attempts to show the sources 

 from which that flora is drawn: — 



^ Garden escapes. 



^ Oxyria digyna was thriving both on the bare shingle and in the sand. 



' This observation was made in the symmer of 1905. In September 1906 we 

 found that though Grimmia fascicularis was still flourishing in the sandy corner 

 mentioned (which is in process of being overgrown with other plants), it had 

 almost disappeared from the shingle. Tiny pieces were to be found pretty 

 frequently on close search, but they did not look at all healthy. Possibly the 

 time of year had something to do with it. All the moss on the shingle consisted 

 of creeping stems without fruit ; I do not know whether this was Grimmia 

 fascicularis in a young stage, or whether it was another moss altogether. 



