10 46 Proceedings of the Royal Irish Academy. 



Present standing of the non-native species (* * *, * * N, * N" *, * N 1ST). 



Of the 55 or so species which, though not deliberately planted where they 

 now grow, may be looked on as not truly native on the island, a large majority 

 are full-blown aliens (* * *), artificially brought from non-native habitats into 

 non-native habitats; and in most cases these are weeds of cultivated land. 

 "Working backwards from those which are most dependent on man to those 

 which are less so, we may divide all the plants which are non-native on 

 the island as follows : — 



(1) Planted species not reproducing themselves from seed nor otherwise 

 spreading ([* * *]). In this category come the various introduced trees and 

 garden plants already referred to (pp. 43-44) and a few crop-plants like Vicia 

 saliva and Lolium pcrcnne. 



(2) Found mainly on cultivated land or in disturbed ground about 

 houses, and, though self-sowing, dependent on the continuance of cultivation, 

 &c, for their continued existence ([***])• Their relative abundance is 

 indicated below, as in the general list of species on pp. 25-27. 



Fumaria confusa, 2. V. Tournefortii, 2. 



Capsella Bursa-pastoris, /. Stachys arvensis, 2. 



Brassica Bapa var. Briggsii, c. Lamium purpureum, /. 



Brassica Sinapis, c. L. hybridum, 1. 



B. alba, c. L. intermedium, 2. 



Baphanus Baphani strum, 3. Galeopsis Tetrahit, 1. 



Stellaria media. /. Chenopodium album, r. 



Spergula arvensis, v.c. Atriplex patula, /. 



Alchemilla arvensis, r. Polygonum Convolvulus, r. 



Chrysanthemum segetum, 1. P. lapathifolium, 2. 



Senecio vulgaris, c. P. Persicaria, /. 



Sonchus asper,/. Euphorbia Helioscopia, /. 



Anagallis arvensis, /. E. Peplus, r. 



Veronica agrestis, 2. Urtica urens, /. 

 V. polita, 2. 



(3) Found chiefly on roadsides and banks, and in pastures. These are in 

 the main less dependent on man than the last group ; and some of them, it 

 would appear, could now maintain themselves indefinitely in the absence of 

 man ([***] or * * *). Some (marked ?) may possibly be of native parentage 

 (K"N*). 



Sisymbrium officinale. Geranium dissectum. 



? Senebiera Coronopus. Trifolium dubium. 



