Nov. 1904.] | BOTANICAL SOCIETY OF EDINBURGH. 41 
Fig. 3l. Fe tetracerum, Ralfs, var. evolutwm, var.n. x 520. 
7 32. - brevispinum, Bréb., forma. x 520. 
5 33. Be paradoxum, Meyen, form from Loch Trebister. 
x 520. 
» 34, 35. forms from Loch Sandy. 
” » ; f 
36. Arthrodesmus triangularis, Lagerh., var. subtriangularis 
(Borge), nob. x 520. 
" 37. Tetmemorus granulatus (Bréb.), Ralfs. Abnormal zygospore. 
x 400. 
Dr. R. Stewart MacDovuGaLL communicated some notes 
by J. Greg. Nicolson, on rare Caithness Plants, with exhibi- 
tion of specimens, including Carex salina, var. kattegatensis, 
Primula scotica, Oxytropis wralensis, and Hierochloe borealis. 
An interesting discussion followed. 
SomE RarE CAITHNESS PLANTS. WITH NOTES. 
By J. GreG. NICOLSON, 
Geographically Caithness is the most northern county of 
the mainland. It is triangular in shape, Duncansby Head 
forming the apex, and is separated geologically from its 
neighbour Sutherlandshire by a line of broken-down schists 
that run from end to end of the base, and formed at one 
time the western “march” of Lake Orcadie. Caithness 
was part of the bed of that old-world lake. The county is 
accordingly comparatively flat towards the north, and is of 
the Old Red formation, the huge faults between the flags 
and sandstones being filled with boulder clay. 
Botanically Caithness is of particular interest, as Alpine 
forms occur on the seashore and the lowlands, and are so 
modified by the high latitude and by their low-lying habitats 
as to give the botanist exceptional difficulty in determining 
the various species. Some of the specimens submitted show 
this peculiarity well. It may be noted that the title of this 
contribution is somewhat ambiguous, as plants may be scarce 
in Caithness and common farther south, or plentiful in the 
county and rare elsewhere. Both sides are touched upon 
slightly. 
Careaz salina (Wahlenb.), var. kattegatensis (Fr.).—Two 
extensive beds of Carex in the lower part of Wick river 
were supposed to be Carex riparia from their general 
