12 
INTRODUCTION. 
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 ©. 
The epidermis of the stem is void of stomata, hut on the under surface of the 
foliaceous part of the frond they are round, abundant, and very large. In the 
fruit, a great difference exists between this and the Annulate Ferns. The thecae 
are transparent and wrinkled, and have only an obscure indication of an annulus ; 
they are not torn asunder irregularly, but open by a distinct longitudinal fissure, 
and are thus regularly two-valved (woodcut of Osmunda, fig. d). They arc not 
fixed at the back of properly developed leaflets, but densely clustered at the top 
into a large erect raceme, the divisions of which correspond to those of the leafy 
portion, indicating that the raceme is formed of metamorphosed pinnae (wood- 
cut of Osmunda, fig. a). The leaflets of the upper part of the frond are also often 
partly changed into thecae of similar character, thus proving the origin of the 
whole. (See Ostnunda.) In Todea, an exotic genus, the thecae are borne on 
unaltered pinnules, as in the Polypodiaceae. 
DISTRIBUTION. — “ Here the distribution of an order in that of a single 
species only, the Osmunda regalis, which prevails chiefly in ihe south-west of 
England, and perhaps the south-west of the Highland tract ; being very frequent 
on the coasts of Cornwall, and occurring in plenty about some of the lochs of 
Argylesliire, and on adjacent islands. The range of the Osmunda extends the 
whole length and breadth of Britain ; but whether it be found on the islets north 
of Sutherland, or west of Islay, is yet unknown. Still, there are considerable 
tracts along the eastern side of England and Scotland, where it is either extremely 
scarce or wholly wanting. The Osmunda flitters from most of the dorsiferous 
Ferns in being adapted to thrive in marshy places, and to flourish on the sea 
shores, sometimes only just above high-water line. Notwithstanding that it 
endures the boreal climate of Sutherland (a county in which the specimens are 
said to be small), the Osmunda is perhaps never seen much above the sea level in 
England, although the general vegetation of the coast in Sutherland approximates 
closely to what is observed at 1000 or 1200 feet of elevation in England. In 
respect to frequency of occurrence, the Osmunda may rank nearly on the level of 
its allies, the Botrychium and Ophioglossum, though rather less frequent than 
either of these.” — Mr. Watson’s MS. 
OPHIOGLOSSACE7E. 
( Contains Botrychium and Ophioglossum.) 
Ophioglossaceaj, Br., Lind., 8 fC . 
OPHioGLOssEae, Spreng. 
Filices, Linn., Smith., Hook., Sec. 
Stachiopterides, WilUl. 
Bivai.va, Iloffim. 
Vai.vatas, Web., Mohr. 
Agyuat^e, Swz. 
STRUCTURE. — The plants contained in this order differ very materially from 
