~rl NOTES ON BOTANY. 



without attempting to give any solution of my own. Perhaps the 

 competition of other species which already occupied the ground 

 was too keen to allow of the new comers establishing themselves in 

 more than a very few localities ; perhaps, on the extreme verge of 

 their possible climatal extension northwards, they could find but 

 few suitable stations. 



But whatever may be the causes which may account for the 

 present very scattered distribution of the rare plants which give a 

 special character to our south-western (and to parts of the Irish) 

 Flora, I should be disposed to think that their arrival within our 

 own area took place at a more recent date than that suggested by 

 Professor Forbes, and probably coincided in point of time with the 

 last period of elevation. I think that none of these southern forms 

 could have survived in our latitude during any part of the true 

 glacial epoch, and that our oldest colonists are not those from Spain, 

 but the northern forms which are now for the most part to be 

 found only on the summits of Scottish mountains. Two plants 

 there are, of American origin, which may have reached us earlier. 

 I refer to Spiranthes Romanzoviana, Cham. [Co. Cork], and 

 Eiiocaulon septangular - e, With. [Western Ireland and Skye.] 

 But these were probably accidentally introduced, perhaps by the 

 agency of birds, so that we have no clue as regards time in their case. 



As typical instances of plants which have reached us from 

 Western France or the Pyrenees, I may mention 



Helianthemum ffuttatum, Mill., from Anglesea and Cork. 

 polifolium, Mill., Somerset and Devon. 



Linum augustifolium, Huds. 



Ulex : All our forms. 



Trifolium Molinerii, Balb, T. Bocconi, Savi, T. strictum, L., 

 from the Lizard. 



Lotus augustissimus, L., and L. liispidus, Desf. 



Ornitliopus ebracteatus, Brot. 



Saxifraga umbrosa, L., and its allied forms from the west of 

 Ireland. 



Umbilicus pendulinus, D.C. 



