28 BRITISH FERNS.
lii
I
Mr. T. B. Flower, after giving me Brecon as one of liis
localities for P. calcareum, adds — “ The Brecon plant would
appear to he intermediate between P. calcareum and P. Dryopteris
and I may observe that Mr. Flower appears well
acquainted with the plants known by these names.
Mr. Francis, in his Analysis of the British Ferns, represents
both species as having the rachis bent at the union of the
branches, a character, according to Smith, possessed by Dryopteris
only ; he also represents the pinnulæ of the second pinnæ
in calcareum completely pinnate, which is far from being the
case in the original specimens : Mr. Francis also says, that
“ its frond is rather large in size,” while Smith speaks ot it as
being smaller than Dryopteris. I t is clear that the same plant
is not intended ; indeed, Mr. Francis’s elegant figure represents
a plant I have not seen.
Finally, Sadler, in his pamphlet, “ De Filicibus Veris Ilun-
gariæ,” a work displaying an intimate acquaintance with ferns,
‘ observes of P. calcareum—“ This species is not yet sufficiently
established; it differs from Dryopteris in its less size, the pinnulæ
also being relatively less and almost entire, the masses of thecæ
more or less confluent, and in having glandular hairs on the
rachis, and sometimes also on the fronds.”
The lateral veins are alternate, and either divided or simple,
according as the pinnula or lobe in which they are found is more
or less divided ; each terminates at the margin, beai'ing a circular
and perfectly naked mass of thecæ near its extremity.
The vignette below represents Eshiug bridge, near Godalming,
in Suiry.
WOODSIA.
W o o d s ia I l v e n s i s and W. H y p e r b o r e a .—Brown, Smith,
Sprengel, Hooker, Sadler, Francis.
Acrostichum Ihense.—Linneus, Berkenhout, Hudson.
Acrostichum alpinum and Ihense.—Bolton.
Polypodium Ihense, hyperboreum.—Swartz.
Polypodium A rwnicum.—Witherin g.
Polypodium fontanum, of the Linnean Herbarium, is identical
with Woodsia hyperborea. Brown.
l o c a l i t i e s .
•En g la n d . . Unknown.
Wa l e s . . . . Caernarvonshire, Llyn-y-coon; on Glyder Vawr and Clogwyn-y-Garnedd; on Snowdon.
S cotland. . Perthshire, Ben Lawers; Forfarshire, Clova Mountains.
I r e l a n d . . Unknown.
T h e genus Woodsia was established by Mr. Brown, in the
Transactions of the Linnean Society of London, vol. xi. p. 170,
and has been adopted by Smith, Hooker, Sprengel, and Sadler.
The genus is founded on certain membranous scales attached
below the thecæ, which Mr. Brown considers as analogous to the
indusium of indusiate ferns. This membrane is somewhat cupshaped,
and its margin is divided into capillary segments, which
appear scattered among the mass of thecæ, or sometimes
incurved over them. Presl has returned the species of Woodsia
to the genus Polypodium. I must confess my opinion that botanists
generally will he unable to detect any analogy between the
bristle-like appendages among the thecæ of Woodsia and the
indusium so obvious in Asplénium and Polystichum, and will
consider these bristles as identical with those which are scattered
over the entire under sm'face of the frond. Nevertheless it
seems so desirable to break into minor sections the heterogeneous
mass of Polypodia, as they now stand, that it is with
pleasure I avail myself of Mr. Brown’s labours in the present
instance.
There are said to he two species of the genus in this country ;
W. Ilvensis, represented by the upper plant in the figure, and
W. hyperborea by the lower. The middle plant of the three is
from a rock above Llyn-y-coon, on the Dog’s Lake, a small pool
lii-1 Mil