564 



PLANTS JAVANICjE RARIORES. 



as regards its extent from west to east. From its striking 

 physiognomy it could 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 Poll/podium {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 

 Perns. 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 JPolypodiuvi {Dipteris) Horsfieldii as 

 having hairs surrounding the sorus, and mixed with the 

 capsules, while in the nearly related species Polyjiod. 

 [Dipteris) WallicJdi, the capsules, even when 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 Polypodium, 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 Polypod. {Dipteris) Wallicliii 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. 



8] Obs. III. — The Pern here described, and the nearly 

 related species Polypodium {Dipteris) Wallicliii, foi'm a very 



