26 
The Scottish Naturalist. 
there are also some 30 species recorded, and likely to be con- 
firmed, but at present not sufficiently vouched for. These three 
groups together give a total of 410 species; and, considering that 
every new district visited hitherto has contributed its quota of 
new records, I am disposed to estimate the Shetland Phanerogams, 
Vascular Cryptogams and Characese, at about 450 species. There 
are also about 75 additional species recorded. These records 
consist, to a small extent, of mere casuals; but, for the most part^ 
I believe, of errors. 
Comparing the above estimate with the Flora of Orkney, we 
find that Mr. Irvine Fortescue's list {Scott. Nat., 1882-3) 
enumerates 494 species ; but many of these are of extremely 
doubtful occurrence ; and applying to this list the same rigid 
scrutiny that has been brought to bear on the Shetland lists, and 
allowing for a few species since recorded, I should accept 450 
species as representing the Orkney Flora as at present known. 
When fully worked, the Orkneys may be expected to yield some 
50 more species than Shetland ; the difference being made up, to 
a large extent, of naturalised cornfield weeds, etc. 
The districts visited last August were Dunrossness and Walls. 
The first comprises the southern portion of the Mainland, including 
Spiggie and Quendal, where Carex incurva grows so abundantly 
on the sand tracts that here cover so large a part of the country. 
As anticipated, this district produced several plants which are not 
found farther north in these islands; but Daucus Carota, Hieraciuni 
Pilosella, and several other common plants which were expected, 
were not met with. Walls hes on the west side of the Mainland ; 
and is remarkable for the innumerable lochs, large and small^ 
which occur in the district ; between 30 and 40 of these were 
examined, though in many cases but partially. Many of the 
larger lochs contain small islands or holms ; and these are of 
special interest, as they alone preserve many plants which around 
the shores of the lochs are eagerly devoured by the sheep. I 
reached one of these holms by \vading, and another by swimming, 
and I hope at some future time to examine them more closely ; 
but to do this a portable boat is required, as most of the lochs 
have no boat on them. While at Walls, the island of Vaila was 
visited, but on it neither Dianthus deltoides nor Rhynchospora alba 
was found. It may be remarked that here the Thrift (Armeria) 
is known by its other name of Sea-pink ; and this may possibly 
