belonging to the genera Oleaudi-a and Polypodium. 327 



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

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

 ( \tcnt that the addition of a new species becomes a subject of 

 msiderable interest. The recorded species are Oleandra nodosa 

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

 1 udies ; O. articulata [Aspidium articulatum, Sw.), found in the 

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

 ill the Philippine Islands and the East Indies ; 0. 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 FiUcum/ tab. 45, is most allied to the fern I have now 

 t he pleasure of laying before the Botanical Society. The latter 

 was recently communicated to Professor Balfour from Tahiti, 

 A\ here 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- 

 i'action in dedicating to him this very fine fern. 



The character of the Hookerian species with which it has to 

 be contrasted is as follows : — 



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

 scenti-hirsuta, iudusiis longe ciliatls. — Hook. I. c. 



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



0. Sibhaldii (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 difi'ering much from O. pi- 

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

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

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

 0. 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 undcscribed, and to })ossess 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 Grammi/is 



