284 
ON THE VARIETIES OF BRITISH FERNS, ETC. 
5 ( 'joroliferum ), lobes proliferous, frequently bearing fruit, Bolt., tab. 2, fig. 6 ; 
i ( acutum ), fronds and lobes pointed, more or less acuminate. 
This resembles the Var//3, but the fronds, lobes, and teeth are much sharper. 
Poly podium dryopteris. 
P. dryopteris , Brit. Flo. (Hook.), 3rd Ed., p. 448 ; 4th Ed., p. 383. 
44 44 Fil. Brit. (Bolt.), p. 52, tab. 28. 
44 44 Bril. Ferns and Allies (Francis), p. 18, pi. X, fig. 5. 
44 44 With. Brit. Bot. (MacGilliv.), p. 380. 
This is so nearly allied to P. calcareum , that in a dried state they have fre¬ 
quently been mistaken ; when growing they may easily be known by the position 
and texture of the fronds, but when dried other points must be examined. Mr. 
Babbington in his 44 Notes” (May. Zool.and Bot., Vol. I., p. 141) says:— 44 P. 
calcareum may always be distinguished from P. dryopteris by being minutely 
mealy in all its parts. Each particle of this mealiness, under a high magnifying 
power, appears to be a minute, stalked gland. I have not been able to find any 
trace of this on P. dryopteris 
Sir W. J. Hooker, in speaking of calcareum , says : — 44 It may be distinguished 
by its more pectinated divisions, and more rigid texture/’ These, I think, will 
prove sufficient diagnoses.* 
Woodsia Ilvensis. 
W. Ilvense , Brit. Flo. (Hook.) 3rd Ed., p. 448 ; 4th Ed., p. 383. 
44 44 Brit. Ferns and Allies (Francis), p. 20, pi. 1, fig. 7. 
44 44 With. Brit. Bot. (MacGilliv.), p. 380. 
Acrosticum Ilvense , Fil. Brit . (Bolt.), p. 14, tab. 9. 
However distinct this and TV. hyperborea may appear to a person having both 
before him, yet when either is seen alone, and more especially that state of the 
former which is sold in London for the latter, it is not always easy to distinguish 
it. It will be best done by the following characters 
In W. Ilvensis the frond is scaly ; the pinnae oblong, deeply cut, and crenate. 
In W» hyperborea the frond is hairy, the pinnae triangulari-ovate ; inciso- 
pinnatifid. 
In my specimens of the latter the fronds glisten with a brilliant lustre, from 
minute crystals, with which the surfaces are scattered. (Query,crystals biwliat? 
—are they foreign to the plant ?) In our present plant also the covers of the sori 
* I may here just mention an accidental error which occurs in the history of the localities of 
this Fern, in Mr. Francis’s useful little work, p, 18, line 13 from bottom j for “ Dry places, Lan¬ 
cashire (sparingly), Hill Cliff, Chesh. and Warrington,” read 64 Dry places, Lancashire-*Sparingly 
Wood, W. of Hill Cliff, Chesh,, near Warrington.” 
