










40 THE BRITISH FERNS. 
they are common to the whole frond, seldom extend upwards beyond 
the node. This mode of development is peculiar to a considerable 
number of the Polypodiew, including genera with both free and 
anastomosing veins; also a portion of Davallia, of which D. cana- 
riensis may be viewed as the type ; the whole forming a truly natural 
group of Ferns." 
In the Desmobrye, “the fronds rise from a terminal axis, either 
in a single alternate series or in a fascicle forming a corona; each 
succeeding frond is produced on the interior side of the bases of the 
preceding fronds, the bases being united and adherent. By the 
successive evolution of fronds, a progressing accessory stem or cormus 
is formed, which varies in being decumbent or erect, short or more 
or less elongated, often assuming the aspect of trees, or creeping on 
or under the surface of the ground, frequently forming caespitose 
tufts. In those species producing their fronds in a single series, 
the developing axis sometimes elongates before the evident evolution 
of the fronds, which are then more or less distant from each other 8 
by this mode of growth is formed a creeping or scandent caudex 
which often assumes the character of a sarmentum, and then appears 
to agree with the mode of growth in the Eremobrye, but it is readily 
distinguished by the epidermis and vascular structure of the stipes 
being continuous and united, forming part of the developing axis 
and not being articulated as in the Eremobrye. The Desmobryce 
include part of Ctenopteris, the whole of the Phegopteris group of 
Polypodium, also Gymnogramma, Goniopteris, Meniscium, and other 
genera of the Polypodiew ; the whole of Pteridew, Aspleniew, and 
with a few exceptions Aerostichee, Aspidiee, Dicksoniew, and 
Cyathee.” 
Such is Mr. Smith’s definition of these groups, which he epitomises 
thus: Desmobrya—Fronds in vernation terminal, their bases adherent, 
united with and constituting the axis of growth: Eremobrya—Fronds 
in vernation lateral, solitary, and ultimately separating from the axis 

