1898-1902. No.19.] STRAY CONTRIBUT. TO THE BOTANY OFN.DEVON. 13 
from the mainland by a strait in which the strong current keeps the water 
open most of the year, or at least before the beginning of the breeding- 
season. The distance from the mainland of North Devon to Castle 
Island is somewhat less than two miles, to Devil’s Island less than one 
mile. Such short distances can, of course, be easily surmounted by 
plant-migration, if, for the transporting of plant species, we should 
attribute any greater importance to those means of conveyance which 
are generally reckoned with for the stocking of islands, viz., wind, birds 
and currents (including floating ice). 
We shall now see what inferences may be drawn from a comparison 
of the plant life of these islands with that of some neighbouring points 
of the larger islands. Firstly it is to be observed that the number of 
flowering plants is nearly the same in both islands, viz., 11 on Castle 
Island and 10 on Devil’s Isle. Two are found in the former alone 
(Draba hirta, Cerastium alpinum), one in the latter alone (Glyceria 
angustata), nine are common. If now the vegetation of the nearest 
points in North Devon is drawn into comparison, we will see that all 
these species are found there except Glyceria angustata, which may 
easily have been overlooked. The flora of Mount Belcher, as far as 
known, reckons 17 species, that of Cape Vera 24, and that of the dry 
limestone ness to the south-west 21. The nearest points in Ellesmere- 
land — Gull Cove and Falcon Cliff — which have the same geological 
nature, affording similar conditions of life as being breeding-places for 
gulls and other birds, show at least 30 and 40 to 50 species respectively . 
The list of higher plants found in North Kent reaches 33. 
Thus it appears that the two islands which are isolated by open 
water, show a considerably poorer flora than that of the mainland 
localities under similar conditions, notwithstanding the short distance 
that separates them from the nearest land (the distance over to Gull 
Cove also is small enough, about 11 miles). The relation of the flora 
of either of these islands to that of Falcon Cliff will be about 1:4 or 
5, to that of Gull Cove 1:3, to that of Cape Vera 2:5 or, more 
probably, about 1:3, as without doubt several species have been over- 
_looked during the short visit to Cape Vera; whereas the flora of the islands 
must be looked upon as thoroughly known, at least as far as flowering 
plants are concerned. If we take the mosses for comparison we will 
get similar figures. Of course it may have happened that I did not get 
some species or other in my collections, notwithstanding that I carefully 
tried to make my moss collections as complete as possible; but I think 
we may look upon the numbers 31 for Castle Island and 385 for Devil’s 
