belonging to the genera Oleandra and Polypodium. 327 



of the most natural in habit of the family of Ferns, and not less 

 beautiful than well-denned. It is at the same time so limited in 

 extent that the addition of a new species becomes a subject of 

 considerable interest. The recorded species are Oleandra nodosa 

 [Aspidium nodosum, Willd.), native of the islands of the West 

 Indies ; O. articulato [Aspidium articidatum, Sw.), found in the 

 Mauritius; O. neriiformis [Aspidium neriiforme, Sw.), growing 

 in the Philippine Islands and the East Indies ; O. Wallichii [As- 

 pidium Wallichii, Hook.), confined to Nepal ; and O.pilosa, Hook., 

 brought by Sir Robert Schomburgk from British Guiana. The 

 last-named species, which is figured by the author in his beautiful 

 ' Genera Pilicum/ tab. 45, is most allied to the fern I have now 

 the pleasure of laying before the Botanical Society. The latter 

 was recently communicated to Professor Balfour from Tahiti, 

 where it was collected by Dr. Sibbald, a gentleman, who, under 

 all the disadvantages arising from the confusion which existed 

 in that unhappy island, during the time of his visit, made some 

 botanical discoveries of great interest ; and I feel no small satis- 

 faction in dedicating to him this very fine fern. 



The character of the Hookerian species with which it has to 

 be contrasted is as follows : — 



0. pilosa (Hook.) ; stipite ad basin articulato, fronde subtus pube- 

 scenti-hirsuta, indusiis longe ciliatis. — Hook. I. c. 



Dr. Sibbald's fern may be thus defined : — 



O. Sibbaldii (nob.) ; stipite ad medium articulato, fronde utrinque 

 pubescenti-hirsuta, indusiis integerrimis. 



The frond is about eighteen inches long, membranaceous, 

 linear-lanceolate like all its congeners, but more or less gradually 

 attenuated below, and in this respect differing much from O. pi- 

 losa ; both surfaces are pubescent, the margin especially, fringed 

 with hairs ; beneath, the midrib is set with long chaffy scales. 

 The arrangement of the sori, although not so regular as in 

 O. neriiformis, is much more so than in 0. pilosa, forming a more 

 or less undulating line on each side, at from two to four lines 

 distance from the midrib. I could have wished that the indu- 

 sium had been in a younger state, nevertheless the organ is quite 

 entire, and there is not the slightest trace of ciliation. 



Another fern in the same collection, discovered in Raiatea, of 

 which there exists only one specimen, appears like the former to 

 be undescribed, and to possess considerable interest from its am- 

 biguous appearance. With a general form of frond bearing a 

 close resemblance to Blechnum Spicant, it has the sori of a Gram- 

 mitis; and totally unlike as it is in habit to any Grammitis 



