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and other early systematic botanists resorted, in the first instance,
to the shape of the frond, than which nothing is more vague,
unnatural, or uncertain, as a generic distinction. Linneus and
his followers have trusted to the shape of the masses of capsules,
whether round, oblong, linear, or indeterminate, whence far
better characters are obtained, hut not such as prove sufficient.
The writer of this, furnislied with a vast collection of Ferns in
tlie Linnean Herbarium, and from that of Sir Joseph Banks,
first suggested an additional principle of arrangement, derived
from the form and insertion of the membranous cover or in-
volucrum, and especially from the direction in which that part
hursts or separates from the frond when arrived at maturity ;
whether, if lateral, at the side towards the margin of the frond,
or of its segments, or towards the rib or vein ; or if terminal,
towards the extremity or contrariwise. This principle is found
to produce very certain distinctions, and to establish the most
natural genera. All subsequent writers on Ferns have adopted
i t .—English Flora, iv. 279. In a few short years we find this
favourite character almost lost sight of, and a fourth, that of the
venation, rapidly superseding it.
Most authors have admitted the importance, for purposes of
nomenclature, of those characters which are spoken of by Smith
as derived from the fructification; hut, until lately, other
characters of equal value, drawn from the situation of the veins,
liave been entirely neglected ; this is now no longer the case, and
I am inclined to believe, that henceforward, in the veins of a new
fern will be sought the characters which shall decide its genus.
At present, I can say but little for the correctness of our writers
on this subject. Presl has published an expensive and highly-
illustrated work, professing to exhibit the venation of every
genus ; hut he has not paid the subject that close attention which
it requires: of the British species few are perfectly accurate;
some, as Allosorus crispus, are either drawn from supposed
memory, or from imagination; and many important and obvious
characters, as the anastomozing veins of Ceterach officinarum, he
has entirely overlooked. I f the exotic species are dravm in an
equally careless manner, the work is of little value.
Mr. Smith, of the Boyal Botanic Garden at Kew, has paid
great attention to the venation of F e rn s; he has prepared an
essay on this subject, which I trust we shall shortly see in print,
and I am sure, from my knowledge of the way in which he has
treated the subject, that when the result of his labours is published,
it will abundantly repay the botanist for a careful and
minute examination. Mr. Smith having, in the most unreserved
manner, communicated to me his own ideas on the subject of
arrangement and nomenclature, I was delighted to find, that,
with very few exceptions, our views were similar: in one or two
instances I was obviously wrong, and in these instances I was too
glad to have the opportunity of rectifying my errors b y the aid
of his superior knowledge of exotic genera. In a few instances
we still differ, and in announcing this, I fear I shall be considered
as pronouncing my own condemnation : still I venture to pursue
my way, and “ by an earlier appearance in the literary horizon,
give myself the chance of what the astronomers call an Heliacal
rising, before the luminary in whose light I am to he lost shall
appear.”
In making out my list of genera I have followed no other rule
than that of priority ; and if, in any instance, I have departed
from this rule, the departure has been entirely unintentional,
and I shall be glad to he informed, in order that I may take an
early opportunity of correcting my error. The characters' which
I have assigned the genera are very concise, perhaps it may be
thought too much so, hut it has been my wish not to swell the
technical portion of a work which is avowedly intended less for
the scientific botanist than for the general reader; moreover, a
repetition of the generic characters will occur in the description
of each species.
With respect to numerous species here treated as varieties, I
have not intentionally omitted one of the characters by which
they may be distinguished, nor have I degraded them from their
former station in order to save the trouble and expense
of figuring them. I have taken as much pains to be explicit in
these varieties as I should have done were they still treated as
species, and each is as correctly figured : the reader must judge
whether they are to he considered species or varieties. I t will
give me infinite pleasure to know that permanent and distinctive
characters have been fomid for Polypodium calcareum, Woodsia
hyperborea, Cystopteris dentata, Polystichum Lonchitis, Lastræa
dumetorum, Athyrium rhæticum, and Asplénium altemifolium :
these would make a noble addition to a list which is at
present a very meagre one ; but until such characters are found
I consider it far better to leave them as I have left them, in the
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