258 
ASPLENIACE.E. 
stem, thus giving to the frond its acutely deltoid form, — and 
lastly, the different situation of the pinnules, — are characters 
which readily distinguish the present from the last species. 
There are three very marked forms of this fern. I have drawn 
the lowest pinnule of each of these exactly of the natural size, 
in order to afford a better opportunity for examining and con- 
trasting their characters. Whatever may be the true value of 
these forms, whether they be more correctly described as species 
or varieties, I will not attempt to say ; but I trust I am correct 
in saying that the distinguishing characters hitherto published 
are scarcely sufficient for the establishment of the former : I 
therefore adopt the same plan as in Filix-femina, and treat 
them for the present as varieties only. 
Asplenium Adiantum-nigruin,Y3iX. ohtusum, (See fig. a, p. 257). 
Asplenium ohtusum, Willdenow ? 
This form of the plant appears to be the Filix pumila petrcea 
nostras of Plukenet, as quoted by Dillenius in the third edition 
of Ray’s ‘ Synopsis ; ’ ^ and the Asplenium ohtusum of Willde- 
now’s ‘ Species Plantarum,’t and of Sadler’s work on the Ferns 
of Hungary.! Concerning the plants of these three authors I am 
compelled, however, to acknowledge that my means of judging 
are very imperfect, and I have given in the Appendix§ the whole 
of Sadler’s descriptions and references, not only as regards the 
present, but also the following forms. The name of ohtusum 
seems to have been given in Kitaibel’s MS. work on the Ferns 
of Hungary, now in the library of the Hungarian Museum of 
Natural History. The principal characters appear to exist in 
the winged stem, smaller size, blunter divisions, and in the whole 
frond being much less divided. Sprengel considers it a variety 
of the next rather than of the present species. 
Asplenium Adiantum-nigrum, var. officinarum. (See fig. h). 
Asplenium Adiantum-nigrum, Sadler. 
This, although placed here as a variety, is the usual form, 
* Filix pumila petrsea nostras, Adianti nigri foliorum semula, saxorum in- 
terveniis prorumpens. — Pluken. Am. 91. In montosis Sussexiee observavere 
D. Manningliam et D. Dillenius. Videtur ad Adiantum-nigrum officinarum 
pertinere et hujus saltern junior planta esse. — Syn. 127. 
f Sp. Plant. V. 341. De Filicibus Veris, &c., p. 30. 
§ See Appendix G. 
