148 
POLYPODIACE^. 
between them.* Lastly, Mr. Wilson remarks, I have never 
had the least difficulty in distinguishing these plants, the first 
by its ovate, the second by its oblong, pinnsB.f All these are 
weighty authorities, but on the other side I find others equally 
entitled to respect. Dr. Robert Brown observes, — These two 
plants are indeed so nearly related that I find myself unable to 
construct for them clear specific characters, and therefore, in 
proposing them here as distinct species, I am, from want of suf- 
ficient materials to determine the question, rather following the 
prevailing opinion than my own.”J Mr. Babington has treated 
them as forms of one species, and makes this observation. — 
“ Our plants appear to form but one species, although they put 
on three very different appearances.” § Mr. J. Backhouse, jun., 
after informing me that he collected some specimens of Woodsia 
at Falcon Clints, proceeds to say, — “ I brought home some spe- 
cimens with roots, and when I planted them they agreed in every 
particular with W, Ilvensis : the first fronds they produced after 
I had planted them were quite different, and had assumed ex- 
actly the form of the Scottish W. hyperhoreay and they are now 
(26th of 11th mo. 1842) changing back again to Ilvensis, so that 
I have no doubt the forms are only two varieties of the same 
species.” Mr. S. Thompson, of York, has seen the plants in 
question, and quite coincides in the opinion here expressed. 
* Polypodium Jiyperhoreum. A praecedente abunde diversum est, idque ma- 
gis glabritie sua, mollitie majori atque gracilitate, quam forma quadam con- 
stanti pinnarum. Radix eodem modo csespitosa sed duplo tenuior. Stipes in 
medietate inter radicem et pinnas infimas articulo perevidenti dividitur, ad quern 
denique dissolvitur et adeo rudimenta ejusdem longitudinis quasi forcipe excisa 
relinquit ; de caetero supra hunc articulum semper glaberrimus atque laevissi- 
mus, crassitie setaB equinse, et colons virescentis. Quoad longitudinum baud 
cedit praecedenti utpote interdum spithamaeum. Pinnae inferiores a se invicem 
distantes vel interstitiis triplo breviores, steriles vel sine fructu omnino semicir- 
culares, utrinque glaberrimee, valde molles et ita tenues ut fere pellucidae : su- 
periores sensim elongantur et pinnatifidae evadunt, atque fructu instruuntur, 
utrinque glabrae excepto fructu. Fructificationis maculae duplo triplove mi- 
nores quam in praecedente, submarginales, in suprema parte frondis confluentes, 
pilis paucioribus et brevioribus piaeditae. Etiam laciniae pinnarum superiorum 
saepius creuatae sunt. — Flora Lapponica, 280. 
I Phytologist, 74. t Trans. Linn. Soc. ix. 172. § Manual, 384. 
