CULTURE OF HARDY FERNS. 
549 
and that of leaf employed in its stead. The 
peculiar manner, however, in which the fruc- 
tification is borne on this part of the plant, 
seems to render it desirable to maintain the 
distinctive name of frond, which, also, is very 
generally adopted, — a still further reason for 
its continuance. An analogy has been traced 
between these fronds and the deciduous 
branches of other plants. 
" In their undeveloped state, the fronds of 
the greater number of the species of ferns are 
coiled up inwards towards the axis of deve- 
lopment, forming a series of convoluted curves. 
The folding up of the frond of ferns, as of 
the leaves of other plants, is termed their 
vernation ; and the peculiar form of verna- 
tion which is most general among ferns, 
and in which the undeveloped parts are rolled 
inwards, or bent like the head of a crozier, is 
said to be circinate. The only British species 
which differ from this in the mode of their 
vernation, are the Botrychium, and the Ophio- 
glossum; and in these the young parts, instead 
of being rolled up, are folded straight. As 
the fronds become developed, these parts gra- 
dually unfold, the more compound of the 
circinate species being in most cases seen to 
have the divisions of the frond also rolled up 
in a similar manner ; in this case, the larger 
divisions first open, and afterwards, in order, 
the pinnje, pinnules, and lobes. In many of 
tlie species the partially developed fronds have 
a very graceful appearance. As the fronds 
become developed, two parts become distin- 
guishable. At the base, more or less extend- 
ing upwards, is a leafless portion, which is 
called the stipes or stalk by some, and the 
stem by others; the latter term, however, moi'e 
properly belongs to the caudex, and is there- 
fore objectionable as applied to any part of 
the frond. Upon the lower part of the stipes 
generally, and sometimes throughout the entire 
length of the rachis, is found a more or less 
dense covering of paleaceous or membranous 
scales ; in some cases, this is confined to a few 
small scattered scales near thebaseof thestipes, 
but in the other cases they are so large and 
numerous as to produce quite a shaggy cha- 
racter. They are most generally regarded as 
portions of disrupted epidermis, occasioned by 
the pressure of the sap beneath. Whatever 
their origin, they are to be regarded as special 
organs, being very constant in their appear- 
ance and development in the same species. 
The upper portion of the frond, extending 
more or less doAvnwards, is leafy, and through 
this leafy portion the substance of the stipes 
is continued onwards to the apex of the frond, 
being, however, distinguished in this upper 
portion by the term rachis. 
The leafy portion of the fi-ond offers many 
states of division, the parts being much in- 
fluenced in size and number by external cir- 
cumstances. Sometimes it is simple or undi- 
vided ; sometimes pinnatifid, or more or less 
deeply cleft ; sometimes pinnate, or divided 
into distinct leaf-like divisions, or pinnce ; 
sometimes bipinnate, when the pinnae are 
themselves pinnate, — occasionally the pinn^ 
are only pinnatifid, or deeply cleft, — this 
second series of pinnae being called pinnules ; 
sometimes the fronds are still more com- 
poundly divided, the pinnules being either 
pinnatifid, or again pinnate. The character 
of the division of the frond is much employed 
in distinguishing the species." 
Respecting the geographical distribution of 
ferns, we are told — 
" The proportion which the ferns bear to 
the phaenogamous portion of the Flora of the 
British Isles, may be taken in round numbers 
as one to thirty-five. In Scotland they are 
computed to hold the proportion of one in 
thirty-one. There is an enormous dispropor- 
tion between the ferns and the rest of the 
Flora in certain tropical islands. Thus, in 
Jamaica, they are one-ninth of the phsenoga- 
mous plants; in New Guinea, D'Urville found 
them to bear the proportion of 28 to 122 ; 
in New Ireland, they are as 13 to 60; and in 
the Sandwich Isles, as 40 to 160. Ferns 
form a very important feature in the vegeta- 
tion of the Indian Archipelago. Upon the con- 
tinent they are found to be less numerous; 
thus, in equinoctial America, Humboldt does 
not state them higher than l-36th; and in 
New Holland, Brown finds them l-37th. 
They decrease in proportion towards each 
pole, so that in Fj-ance they stand as l-63d, 
in Portugal as l-116tb, in the Greek Archipe- 
lago as i-227th; and in Egypt as l-97lst of 
the flowering plants. Northwards of these 
countries their proportion again augments, 
and they are found to form 1-3 1st of the phae- 
nogamous vegetation of Scotland, l-3oth in 
Sweden, 1-1 8th in Iceland, 1-lOth in Green- 
land, and l-7th at North Cape." 
We shall now select at random from the 
body of the work a few of the engravings and 
descriptions, as specimens of the matter and 
illustrations : — 
" Genus XIV. Trichomanes, Linncens. — 
Fronds pellucid ; veins prominent, branched, 
either ending at or within the margin, or ex- 
tended free into a filiform receptacle, around 
which the spore cases are attached within an 
elongated cup-shaped involucre of the same 
texture as the frond ; receptacle more or less 
exserted. Name derived from the Greek 
trichos (a hair), and mania (excess), in re- 
ference to the exserted hair-like receptacles. 
"1. Trichomanes radicans, Swartz (Bristle 
Fern) ; fronds 3-4 pinnatifid, pendulous, angu- 
lar-ovate, glabrous ; segments linear entire, or 
