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 Horne, 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 admirably 
adapted for being swept with spray during every stiff easterly 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 
Ramalina 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 tfie rocks, the vanguard of the phanerogamic vegetation 
appears. This is usually in 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). Algae 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 Algae, 
and are often quite destitute of such plants. The larger Fungi also appear 
to be very scarce. Besides the lichen-covered rocks already mentioned, the 
