1 905-1906.] Fo7'i)iatio7i and Flora of a Shmgle Island, 305 



Chief sources of the flora. — As shown in this list, out of 

 143 species on the Shingle Island, 68 were also growing in 

 the adjoining fields, 76 in the riparian strip, and 33 on 

 Eilean a Phortaire ; 9 belong to mountainous situations, 

 and were doubtless brought down from the hills by tributary- 

 streams ; and 9 are escapes from gardens a little way up- 

 stream.^ Of the 11 untraced species, I believe that 3, — 

 Juncus effusus, J. lamprocarpus, and Phalaris arundinacea, — 

 though not recorded from the riparian strip, were probably 

 growing there in the bed of the winter stream ; ^ so there 

 are really only 8 which have not been referred to any 

 definite source. 



Disregarding for the moment those plants which occur 

 in more than one of these sources, we find that the fields by 

 themselves supply 31 species, the riparian strip supplies 28, 

 and Eilean a Phortaire 7. From these figures it would 

 appear that the fields and the riparian strip are the main 

 sources of the flora, and are of equal importance ; but we had 

 not time to examine Eilean a Phortaire nearly so completely 

 as the other two localities ; and we imagine that a thorough 

 search would show this island to be almost as important a 

 source as the others. In any case, the list shows that an 

 overwhelming proportion of the plants come from the im- 

 mediate neighbourhood, as only 7 or 9 out of the 143 species 

 appear to have travelled any great distance.^ 



Comparison of the floras of the fields, the riparian strip, and 

 the Shingle Island. — On comparing the floras of the fields, the 

 riparian strip, and our Shingle Island, it was noticeable that 

 each had certain plants peculiar to itself, besides others 

 growing there in abundance, while almost lacking in the other 

 two places.* 



' CEnothera biennis we did not actually trace to a garden, as we did the other 

 8 species ; but there can be little doubt that it was a garden escape. 



" We investigated the Juncacese last ; and the autumn floods unfortunately 

 prevented our completing them, or making any record of the purely aquatic 

 plants in the bed of the winter stream. 



' That is, the mountain plants. Two of these, Galium boreale and Plantago 

 maritima, are not so exclusively mountainous ; and the latter was growing plenti- 

 fully in the neighbourhood of Dalmally, even along the roadsides. 



* In the succeeding pages we have not taken into consideration the Graminese, 

 because we were not familiar enough with them to form a fair estimate of the 

 abundance of many of the species. 



