328 
HYMENOPHYLLACE.E. 
H. timh'idgense, it having been found in the most distant parts 
of the globe : Europe, Africa, New Holland, and South America. 
There is a very good figure of this fern in Sowerby’s ‘ Eng- 
lish Botany.’^ 
With respect to the name, British authors seem agreed in 
calling it H, Wilsoni ; but, numerous as are our descriptions, 
not one appears to me to describe the plant so accurately 
as that by Willdenow of H. unilaterale : this I have quoted 
below,t and I think few botanists will hesitate in deciding that 
it was intended for a species very similar to our H. Wilsoni, I 
have never seen authentic specimens of Willdenow’s plant, and 
therefore fear to adopt the name ; moreover, Willdenow does 
not mention his unilaterale as an inhabitant of Europe. The 
subject is, however, well worth investigation ; for, much as I 
honor the name of Wilson, I should not hesitate to adopt the 
prior name could it be established that the species were identical. 
The species as British was first distinguished from the preceding 
by Mr. Wilson, who, in a letter to me, observes, I have had 
considerable difficulty from the very first in procuring for Hy- 
menophyllum Wilsoni an exact description : the pinnae are not 
pinnatifid, as in H. tunhridgense, but more properly of a lobed 
or triangular form (rhomboid in the other species). It may per- 
haps aid the illustration to say that H, tunbridgense has the 
pinna with a central axis, while nothing of the sort can be de- 
dected in H. Wilsoni ; and that if you were to cut away the 
outer half of the pinna of H. tunbridgense you would then 
reduce it to the shape of H. Wilsoni. By this character the 
species may be recognised in a barren state.” The first 
* Eng. Bot. Snpp. 2686. 
f Hymenophyllum unilaterale, W. H. frondibus pinnatis, pinnis digitato- 
pinnatifidis secundis, laciniis linearibus sub-bifidis ser’atis, soris supra axil- 
laribus solitariis, indusiis integerrimis, rachi stipiteque teretibus glabris. W. 
Caudex repens filifornais crassitie capilli. Stipes pollicaris capillaris teres 
glaber. Frons sesqui- vel bipollicaris pinnata, circumscriptione lineari-lanceo- 
lata. Pinnae inferiores et superiores minores, intermediee tri- vel quadri-line- 
ares digitato-pinnatifidae glabrae secundae. Laciniae lineares indivisae vel 
bitidae obtusiusculae serratas. Racliis teres gltibra. Sori supra-axillares sessiles, 
Indusia oblonga obtusa integerriina,- — W. Sp. PI, v. 521 (1810). 
