564 PLANTS JAVANICE rariores.
as regards its extent from west to east. From its striking physiognomy it conlcl not, I think, have escaped my notice.
" It grows in clusters with fronds of different height, the tallest often equalling five or six feet.
" Its range is above that at which rice can be cultivated in Java, which is about 5000 feet above the level of the ocean. It springs from the black vegetable mould, which very generally covers the mountains of Java."
Obs. II. — Before entering on the subject of the affinities of Polypioduim {Dipteris) Horsfieldii, there are some parts of its structure deserving of notice.
In the first place, the existence of the complete circle of vasa scalariformia separating the ligneous or fibrous vessels of the caudex into an outer and inner portion, though not peculiar to Dipteris, seems to be of rare occurrence among Ferns. It exists, however, in the caudex of Platyzoma (though not in that of Gleichenia) ; and I have observed it also in some (probably it will be found in all) species of Anemia.
I have described Poly podium {Dipteris) Horsfieldii as having hairs surrounding the sorus, and mixed with the capsules, w T hile in the nearly related species Polypod. {Dipteris) Wcdlicliii, the capsules, even w r hen fully formed, are imbedded in a gum-like pulpy substance, the remains of which may always be found, even after the spora are dis- charged. In the dried specimens examined this pulpy substance had no appearance of organization ; in the living plant, however, it will probably be found to be minutely cellular, as I have observed in the nascent sori of several species of Poly podium, in which the production of this cel- lular pulp precedes the formation of the capsules, and is generally evanescent soon after they become visible. The peculiarity in Polyjwd. {Dipteris) Wcdlicliii probably, there- fore, consists merely in the longer duration of this substance, in which perhaps the capsules of the greater number of Polypodia are formed.
3] Obs. III. — The Fern here described, and the nearly related species Polypodinm [Dipteris) Wallichii, form a very
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