belongmg to the genera Oleandra and Polypodium. 327 
of the most natural in habit of the family of Ferns, and not less 
beautiful than well-defined. 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. articulata {Aspidium articulatum, Sw.), found in the 
Mauritius ; O. neriiformis {Aspidium neriiforme, Sv/.), growing 
in the Philippine Islands and the East Indies j 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 Filicum,^ 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 Hr. 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 articulate, fronde subtus pube- 
scenti-hirsuta, indusiis longe ciliatis. — Hook. 1. c. 
Hr. Sibbald^s fern may be thus defined : — 
0. Sibbaldii (nob.) ; stipite ad medium articulate, 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 O. 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 Gramrnitis 
