Clare Island Survey — Phanerogamic/,. 10 37 



maintained themselves ; nor, from a very remote period, can any native 

 grazing animals have been present, which might, at certain spots, have 

 enriched the land for the support of those plants which like gross feeding. 



Among the groups of plants which are introduced by man, and come 

 under section (3) of the classification on p. 33, the more important are : — 



(a) Plants deliberately brought in, as seeds or roots, for agricultural or 

 aesthetic purposes, or for food. These include trees planted for shelter, 

 crop plants and crop seeds ; seeds, &c, used as human food, or for feeding 

 cattle, fowl, &c. ; and the contents of the kitchen-garden and flower-garden. 



(b) Plants which come accidentally with these, especially as impurities in 

 seed. The main body of alien weeds comes under this head. 



(c) Plants which arrive attached to animals, or to inanimate objects 

 brought in by man. Thus, men, cattle, and sheep may carry seeds attached to 

 their hair or feet ; and clothing, timber, and many other materials brought 

 by man serve as carriers of seeds (see note on Matricaria discoidea, p. 47, 

 and on mud from the mainland, p. 54). 



On Clare Island no portion of the vegetation can be claimed as absolutely 

 undisturbed, except that occupying certain portions of the sea-cliffs, where 

 the ubiquitous sheep are unable to climb, and one or two other spots (see 

 p. 40, infra). Even on the great scarp of Croaghmore, among the alpine 

 plants, one comes on natural shelters under overhanging rocks, and here 

 the sheep have left their mark behind them in the little colonies of Poa 

 annua, Stellaria media, Oerastium glomeratum, &c, which are here clearly 

 exotic. Nevertheless, the heath area, which occupies about two-thirds of the 

 island, is still comparatively in its primitive condition. It is on the farm- 

 land that man's influence is especially seen ; here we get every gradation 

 from an almost undisturbed native flora to a flora which is wholly artificial. 



In order to determine the standing of the doubtful members of the flora, 

 the range and habitat of each species on the island were studied, and the 

 means by which each is dispersed ; also its distribution and standing on 

 the adjoining mainland, in Britain, and on the Continent. 1 To discover 

 what plants are being introduced at the present day, samples of the seed 

 brought to the island for agricultural purposes were intercepted and 

 examined 2 ; certain accidental means of introduction were also investigated. 



In attempting to express with any accuracy the present standing of 

 species as regards their being native or introduced, we are really trying to 



1 As regards observations on these points I would acknowledge the kind assistance I received 

 from Miss M. C. Knowles. 



2 I would acknowledge niy great indebtedness to Dr. G. H. Pethybridge, in charge of the Seed- 

 testing Station of the Department of Agriculture and Technical Instruction, and his assistant, 

 Miss E. Hensman, for analyses of these samples. 



