THE ALPINE BLADDER FERN 
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in pairs upon opposite sides of the racliis. The pinnae, too, 
are more divided, becoming in well -developed specimens 
almost tri-pinnate. The general form of the frond is egg- 
shaped, or broadly lance- shaped, broadest in the middle, 
tapering to a point at the apex, and tapering very slightly 
towards the base, the lowest pair of pinnae being slightly 
shorter than the pair next above it. The latter and the 
third pair are usually the longest, and from them the pinnae 
gradually diminish in length to the apex of the frond. 
They are divided into short, bluntish pinnules, alternately 
placed on each side of their mid-stems, and diminishing in 
length towards their apices. The pinnules are deeply 
cleft, sometimes almost divided down to their mid- 
veins ; the lobes into which they are cleft being what is 
called dent-ated, or toothed — bluntly so. The system of 
veins is extremely and elaborately beautiful. From the 
mid- veins of the pinnules venules branch into the lobes, and 
from these venules veinlets again branch — one veinlet being- 
carried into each of the marginal teeth, into which 
the lobes are divided. Near the margins of these leafy 
teeth are borne the roundish sori scattered pretty evenly 
over the under-surface of the frond but not, as in 
Fragilis, becoming confluent or run together. The 
rootstock is small and tufted, and the fronds of a 
vivid green colour and herbaceous. There have been 
no varieties of this charming little Fern discovered — a 
fact which gives it a greater claim to rank as a distinct 
species. 
Distribution. — Both in Europe and in Asia Cystopteris 
alpinct has been found — in Europe most abundantly in the 
Alps. It is an inhabitant of Belgium, Croatia, Dalmatia, 
France, Greece, Hungary, Italy, Spain, Sweden, and Tran- 
sylvania. In Asia its discovered habitats are in Asia Minor. 
I11 the British Islands this Fern is extremely rare as a wild 
