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speciosum or radicans, a native of the Atlantic Islands and of 
Ireland. 
Genus Hymenophyllum. 
In which the receptacle does not project beyond the cup, a trivial 
and seemingly very unimportant character. Example, Hymenophyl- 
lum unilaterale of Willdenow, the smallest of British ferns, very com- 
mon on stones and trunks of trees near waterfalls in the North of 
Europe, some parts of Scotland, and the South-west of Ireland. 
- About a hundred other names of species exist. 
Pres], in his beautiful work intituled ‘ Hymenophyllacee,’ pub- 
lished in Prague, in 1843, has given a complete and masterly digest 
of this previously obscure and little-known family, which he divides 
into nineteen genera, exclusive of Loxsoma. It is the first and only 
instance within my knowledge in which a natural group of ferns has 
been carefully worked out. The genera in addition to Trichomanes 
are, Feea, Hymenostachys, Lecanium, Cardiomanes, Ragatelus, Ce- 
phalomanes, Neurophyllum, Microgonium, Abrodyctyum, Didymo- 
glossum, Meringium, Hemiphlebium, Leptocionium, Myrmecostylum, 
Ptychophyllum, Hymenophyllum, Spherocionium and Hymenoglos- 
sum. 
Order CORMOPHYLLACE. 
In the Cormophyllacee the caudex is generally erect, but some- 
times prostrate; its growing extremity 1s always composed of unde- 
veloped fronds ; it is almost invariably without scales; the fructifica- 
cation is formed before the unfolding of the fronds; their stipes is 
generally densely covered with chaffy scales; the stipes are spatulate 
at the base, sometimes wholly, always partially, clasping the caudex, 
with which they are continuous, and of which their bases eventually 
form a part. There are probably many families: three are very fami- 
liar to botanists. 
Family CoRMOPHYLLEA. 
The caudex vertical, developed above the surface of the ground, 
forming a true trunk, much resembling that of phenogamous trees. 
All the species may be comprised in the 
Genus Cormophyllum, 
the characters of which will of course be those of the family. This 
genus contains the tree-ferns, of which one hundred and forty species 
