10 24 Proceedings of the Royal Irish Academy. 



The most abundant plants of the scarp include : — 



Silene acaulis, Sedum Rhodiola, 



Saxifraga decipiens, Oxyria digyna. 



S. umbrosa, Hymenophyllum unilaterale — 



all of which occur in great profusion Silene acaidis, and also Hymeno- 

 phyllum unilaterale + Mniv.ru hornum form large bosses (Plate TL, fig. 1); 

 Sid urn Rhodiola and Oxyria diyyna occupy all the rock crevices: Saxifraga 

 umbrosa and S. decipiens are everywhere. Small falls of stone and earth are 

 continually dragging down clumps of vegetation. Silene acaidis suffers 

 particularly in this way, but easily maintains its abundance by means of 

 seedlings, despite the ravages of the slug Arion ater, which feeds voraciously 

 upon the blossoms (Plate Y., fig. 2). 



The vertical limits on Clare Island of some of the plants are given below; 

 but no systematic observations on this point were undertaken : — 



Coehlearia officinalis, 1 to 1300 



Silene acaulis, 400 to 1450 



S. rnaritima, to 1000 



Lychnis diurna, to 1000 



Saxifraga decipiens, to 1800 



S. umbrosa, to 1500 



Sedum Ehodiola, 150 to 1450 



S. anglicum, to 1450 



Angelica sylvestris, to 1200 



Armeria maritima, to 1300 



Oxyria digyna, 600 to 1400 

 Hymenophyllum unilaterale, to 1500 



Lastrea aemula, to 1500 



Aspleninm marinum, to 500 



4, LIST OF THE TLOEA OF CLAEE ISLAND. 



In enumerating the flora of Clare Island, I shall adopt the method most 

 saving of space — to list the plants in columns, with no further comment than 

 the figure or letter which follows each The figures 1, 2, 3, are used when 

 the species were seen in only one, two, or three stations on the island ; 

 r. signifies rare ;/., frequent ; c, common ; ex., very common : I., local. For con- 

 venience of statistics, only species and sub-species (according to the standard 

 used in "Irish Topographical Botany") are included in this hist, varieties 

 being separately dealt with below. The present list includes all species found 



1 " " signifies the lower limit of terrestrial vegetation. 



