216 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 
It is somewhat remarkable that, though Ben Lomond is but 
twenty-seven miles distant in a direct line from Glasgow, and is 
visited annually by many botanists, it should only at this late 
day be telling us that Cystopteris montana belongs to its flora, and 
so to the flora of Stirlingshire. Through the 
kindness of Mr. Bennett, I am in a position 
to give particulars in full of the other five 
counties in Britain in which C. montana has 
been found. They are: (69) Westmoreland, 
on Helvellyn; (88) Perth, Mid, on the Bread- 
albanes; (90) Forfar, in Caenlochan Glen ; 
(92) Aberdeen, South, in Glen Callater; and, 
lastly, Argyle, Main, on Ben Laoigh, on its 
north-west side, as I have been kindly in- 
formed by Mr. G. Claridge Druce, F.L.S., who 
Lowest pinna of Cystopteris was the discoverer of it there. C. montana 
fication). Ghowing Suc was first found in Britain by Mr. W. Wilson, 
on Ben Lawers, in 1836. Its foreign distribution, according to 
Sir J. D. Hooker, is in “arctic and alpine regions in Europe, 
Asia, and America.” 
The Ferns of the British Isles, leaving out of account Hymeno- 
phyllum, Trichomanes, Osmwnda, and the Ophioglossacece,—the 
fructification in which is exceptional,—are, as we know, classified 
mainly on the basis of the structure and position, on the back of 
the frond, of the sor? or groups of sporangia, those minute stalked 
capsules in which the microscopic spores are contained. These 
sori may, as regards their position, be either,— 
(1) Placed along the edge of the frond (marginal), and covered 
by an involucre (called also an imdusiwm), which is 
continuous with the frond, as in Adiantum, Pteris, 
Cryptogramme, and Lomaria ; or 
(2) On the back of the frond (dorsal), linear in shape, 
protected by a linear involucre, as in Aspleniwm and 
Scolopendriwm ; or 
(3) On the back of the frond (dorsal), globose in shape, and 
with either a lacerated, hooded, orbicular-peltate or 
reniform involucre, as, respectively, in Woodsia, 
Cystopteris, Aspidiwm, and Nephrodium ; or 
