1909-10.] Flora of Scottish Lakes. 175 



is maintained by rabbits, which abound. There is no sandy shore at any 

 part of the island, because nearly everywhere rock abruptly enters the sea. 

 There is, however, at the north-west end a little beach about 20 yards long, 

 composed entirely of finely broken shells ; and at the south-west end, 

 immediately to the east of some bold dolerite stacks that stand out in the 

 water, there is a small stretch of pebbly beach. No vegetation grows upon 

 either of these places, so that the usual maritime sandy or pebbly shore 

 plants are absent from the island. Between the rocks, especially upon the 

 low-lying east side of the island, and even at the highest parts, numerous 

 little pools are formed by the collection of rainwater in the hollows, and a 

 few semi-aquatic plants occur at such places (fig. 121). Near the .southern 

 point of the island there is a small damp, open cave, which was probably 

 excavated by the sea at a former period, when the 25-feet raised beaches 

 were formed upon the adjoining mainland. This cave has been excavated 

 in a reddish material, comparatively soft and easily crumbled, which, as 

 Messrs Peach and Home, of the Geological Survey, inform me, is due to the 

 decomposition of the exfoliating teschenite lying in a fissure of that rock. 

 This place contains a few plants not observed elsewhere upon the island, and 

 it will subsequently be referred to as the cave. Upon the east side of the 

 island the rocks, by their gradual rise from the sea (fig. 118), are admirabl}' 

 adapted for being swept with spray during every stiff ea.sterly breeze, so 

 that over a rather wide zone these rocks are perfectly bare of soil, and the 

 only vegetation that can exist consists of certain maritime lichens. These 

 grow in great abundance and cover almost every rock, imparting a vivid 

 coloration to the otherwise sombre aspect, the grey Lecanora parella, the 

 brown Physcia aquila, the orange Physcia parietina, and the glaucous 

 Eamalina scopulorum being particularly noticeable (fig. 120). A little 

 higher up the incline, where the drenching spray has been insufficient to 

 entirely wash away all soil, and where some mould has been retained in the 

 interstices of the rocks, the vanguard of the phanerogamic vegetation 

 appears. This is usually i)i the form of dwarf cushion-like tussocks of 

 Armeria maritima, which adds its own peculiar charm to the coloration of 

 the lichen-besprinkled rocks around (fig 119). The Armeria in such situa- 

 tions produces roots of surprising length, which penetrate the fissures of the 

 rocks until an agreeable soil is reached (fig. 123). Algffi are generally scarce, 

 and cannot be said to take any part in the formation of the plant-covering 

 of the island. The same remark applies to the rocks at the margin of the 

 sea, for they are in most places singularly poor in species of marine Alga?, 

 and are often quite destitute of such plants. The larger Fungi also appear 

 to be very scarce. Besides the lichen-covered rocks ah-eady mentioned, the 



