s 
INTRODUCTION. 
Tricliomanes form an order separate from the Polypodiaceae. Besides the dif- 
ference in the fruit, the texture of the leaves is much more cellular than in the 
last order. The stem of each is quite smooth and round, and contains but one 
bundle of spiral vessels which is solid and forms an axis. The Theca; arise 
from the veins still more evidently than even in the preceding order, as the re- 
ceptacle is in the place of a lobe of the leaf. The laminae of the lobe contract- 
ed form the valves of the receptacle, and its vein or nerve exists as a central 
column, covered with fructification ; in Hymenophyllum terminated thereby, 
in Trichomanes the vein is prolonged much beyond the thecae. The root of 
Trichomanes is thick, black, and very hair}', that of Hymenophyllum very 
long, creeping, and matted together. 
GEOGRAPHY. — The native habitations of these elegant and delicate plants 
arc moist rocks, and they are so impatient of restraint, that one method alone 
has succeeded in domesticating them, all the usual art and attention of the 
gardener ending in disappointment. Mr. Ward, of Wellclose Square, finds 
them and very many other species thrive well in air-tight cases, suffering the 
moisture which their pores exude to be absorbed again by the roots, while at 
the same time they are preserved from external injuries and sudden changes 
of temperature. Mr. Mackay remarks, in his “ Flora Ilibernica” (lately pub- 
lished), that he has succeeded in cultivating the Trichomanes to perfection, by 
placing the pot in which it is planted in the greenhouse, under a hand glass, a 
method which, it will be seen is exactly analogous to the foregoing, as Mr. 
Ward’s air-tight glasses are kept in the house. 
OSMUNDACEAS. 
( Contains only the genus Osmunda. ) 
OsmundacejE, Hr., Kaulf., Lind., Hook., Agard . ; — Osmundex;, Spreng. ; — 
Schismatoperides, Willd . ; — Spurije Gyrataj, Swz.; — Rimatjj, Mohr.; 
— Acrogyratje, Bernh . ; — Exannulat.e of Modern Authors. 
STRUCTURE. — This order varies very little from the two former, except 
in the fructification. The rachis is similar in vernation and structure, the 
mixed vessels are arranged in the indigenous species in part of a circle like the 
letter (g. The cuticle of the stem is void of stomata, but on the under surface 
of the foliaceous part of the frond they are very large, round and abundant. 
In the fruit, a great difference exists between this and the Annulate Ferns. 
The thecae arc transparent and wrinkled, but not ringed ; arc not torn asunder 
irregularly, but open at a distinct longitudinal fissure, and are thus shown to be 
regularly two valvcd. They arc not fixed at the back of a leafy frond but 
