up tho group of Acrogens, which is the real equivalent to tho
endogenous and exogenous groups of phainogams.
Mr. Newman, follovdng Mr. Smith, has proposed a modification
of his plan, which is, however, open to the same objections. He at
first proposed to form four groups : Eremohrya—Ferns whose fronds
are produced from any part of the rhizome except its point, and
always articulated with it ; Chorismohrya—Foms whose fronds are
produced as in tho preceding, but not articulated : Desmohrya—
Foms whose fronds aro produced only at the point of the erect or
suberect corm-Kke rhizome, and not articulated : Orthohrya—Ferns
having the vernation straight. This arrangement has been subsequently
curtailed, and the following scheme substituted*—A
primary group, the Filicales, including thoso Ferns which have the
spore-oases encircled by a ring, are divided into two lesser groups :—
the Rhizophyllacece, in which the fronds are attached to a rhizome,
or root ; and the Cormopliyllaceai, in which they are attached to a
cormus or trunk. Another primary group, the Osmundales, including
the rest of the Ferns, namely those which have their spore-oases
detached from the leaves, and not encircled by a ring, comprise the
Osmtmdacece, with oiroinate vernation, and a woody trunk ; and the
OphioglossaoecB, with straight vernation, and a succulent trunk.
That system of classification which is based on the vascular
system of tho frond, taken in conjunction with its fructification, is,
we think, in every respect to be preferred, and we shall hero
explain that modiiioation thereof which we have adopted f after
much consideration.
All Ferns, taking the term in its widest application, are referrihle
to one of these groups, namely—■
O p h io g l o s s a c e ^ — P oLYPODiACE.®— M a h a t t ia c e z e .
Of these, the Ophioglossaeece and MarattiaeecB are hut small groups,
* Newman, History o f British Ferns, 3 ed. x.
+ Moore, In d e x Filicum, Synopsis ix,
while the Eolijpodiacem include tho greater portion of all known
Foms. Those three groups may each he regarded as a distinct
order of plants, forming together tho F i l i c e s or Forns.
Tho groups thus indicated aro distinguished from each other hy
the nature and structure of thoir spore-oases. The presence of tho
annulus or ring around the spore-oase, in some form or other, either
nearly completely surrounding it, or in a more or less rudimentary
condition, is the distinctive peculiarity of the Polypodiaeece, while
tho Marattiacece and the Ophioglossaeece, aro distinguished by the
absence of any such ring, rudimentary or otherwise. Those obvious
distinctions, to which, as they aro connected with certain other
differonoos which serve tho same purpose, the initiated seldom have
to resort, are tho foundation of all satisfactory inquiries into the
nomenclature of a Fern.
The Marattiacece and Ophioglossaeece are distinguished from each
other by very obvious characters. Tho Marattiacece are dorsiferous,
that is, bearing their sori on the back or under surface of their
fronds, as is commonly the case among Forns. The Ophioglossaeece,
on the contrary, always have their spore-bearing or fertile fronds
contraotod, so that whde the spore-cases aro produced marginally,
they seem to occupy the whole surface; such fronds aro called
rachiform, heoause they want the flat leafy expansion of ordinary
fronds, and are reduced to the appearance of mere ribs or rachides.
The Ophioglossaeece are few in number, and present little diifer-
enoo of structure, so that it has not been found necessary to range
the genera in secondary groups or tribes. The Marattiacece, however,
form three Kttlo groups of genera, separated by differences of some
importance; these tribes are called the Marattinece, the Kaulfussinece,
and the Banceinece. The Marattinece have their sori ranged in two
lines facing each other, forming distinct oblong masses. The Kaulfussinece
have distinct circular sori, the spore-cases of each sorus
being concrete into a single annular series, and furnished with