THE BRITTLE BLADDER FERN. 261 
In some or other of its many forms, this fern is dispersed widely 
over the world. Tt occurs throughout Europe, from Iceland and 
Lapland through Norway, Sweden, Russia, Denmark, Holland, 
Belgium, Germany, Switzerland, France, Spain, Portugal, Italy, 
Dalmatia, Croatia, Hungary, and Transylvania, to Greece, Turkey, 
the Crimea, and the Russo-Caucasian provinces. In Asia, it is 
found in the regions of the Ural, the Altai,and Lake Baikal in 
Siberia, extending to the frontiers of Chinese Turkestan, Kamt- 
schatka and Unalaschka ; also in Asia Minor, Erzeroum, Koordistan, 
and northern Persia; in Affghanistan, Kashmir, Kunawar, Simla, 
Nepal, Thibet, and the Himalayas. In Africa, we have records of 
its occurrence in Abyssinia, and at the Cape of Good Hope, as well 
as in North Africa; and it is found in the islands of Madeira, 
Teneriffe, the Canaries, and the Azores. Over these north-African 
islands extending to Malaga, is also dispersed a plant (sempervirens) 
which in its evergreen habit, tough stipites, and hairy indusia, has 
strong claims to specific rank. In America the species extends from 
Greenland, Labrador, Kotzebue’s Sound, and the countries border- 
ing the Polar Sea, through north-west America, to Canada, the 
United States, California, Mexico, Guatemala, and Columbia: in 
the latter warmer countries becoming the var. nigrescens of Hooker. 
At Xalapa, as well as in Guatemala, and Quito, and on the Andes 
of Peru, also occurs a peculiar slender narrow form of the dentata 
series. The plant is again found in the West Indies: Jamaica, 
Cuba, and the Bahamas; and in America, in New Grenada; 
in Chili, at Mendoza, and at Port Famine. C. fragilis has also 
been recorded from Tasmania. Many of the reputed habitats 
of the central parts of North America belong to C. tenuis, a species 
which, though perhaps not distinguishable by its fronds alone 
from some forms of C. fragilis, is totally different in habit, having 
a widely-creeping rhizome. 
This is a pretty little Fern for the cultivator, affording in its 
different forms some variety in his collection, and thriving well 
either in cool frames or greenhouses planted in pots, or on the open 
rock-work in shady and somewhat moist localities which enjoy a 
moderately pure atmosphere. The soil may be composed of light 

