VEGETATION OF THE RAIN-FOREST. 35 



where in the region, others of which are epiphytes at lower altitudes, 

 as : Peperomia verticillata, Tillandsia complanata, Isochilus linearis, Bryo- 

 phyllum calycinum, Epidendrum verrucosum, Polypodium incanum, 

 Polypodium lanceolatum, Polypodium plumula, Cheilanthes microphylla, 

 and Asplenium dimidiatum. 



THE RIDGES. 



The Ridge Forest of the Blue Mountains is stunted, open, and 

 relatively xerophilous in the entire make-up of its vegetation. It pos- 

 sesses few of the species characteristic of ravines, at the same time that a 

 distinct set of characteristics are the salient ones in determining its 

 physiognomy. The main ridge of the Blue Mountains at 5,600 to 

 6,000 feet altitude exhibits the most marked type of Ridge Forest, 

 excepting at the low gaps. Radiating from the main ridge along the 

 principal lateral ridges and from them in turn along the lesser water- 

 partings extend the narrow stretches of Ridge Forest, retaining much 

 the same character down to 4,500 feet and differing only in minor 

 particulars on the windward and leeward sides of the range. On 

 leaving any part of the Ridge Forest and descending to a distance of 

 100 feet the characteristics of the slopes will be found to prevail. 



The Ridge Forest presents a very level canopy when viewed at a 

 distance, but it varies greatly in the density or openness of its stand of 

 trees. In the most dense stands, however, the trees are sufficiently 

 far apart for their crowns not to meet, which fact, together with the 

 sparsity and openness of the shrubby vegetation, allows considerable 

 light to reach the forest floor. The trees vary from 18 to 30 feet in 

 height, but are of incommensurate trunk diameter, often making 2 and 

 3 feet in thickness with a height of 16 to 20 feet. The largest trunks are 

 bent and gnarled or prostrate on the ground, and so interlocked with 

 dead and decaying trunks that the forest floor is seldom clear for a 

 space as much as 15 feet square (see plate 17). 



The under-trees are scant, but young individuals of the principal 

 tree species are common, as are also xerophilous shrubs, chiefly occur- 

 ring in the most open parts of the forest. The more open the forest 

 the more completely is it occupied by the bamboo, which literally fills 

 the forest from the ground to a height of 6 or 8 feet; or in other open 

 places the bamboo is absent and dense thickets of ferns cover the 

 ground to a depth of 4 or 5 feet, excluding all smaller vegetation. 

 Only in the portions of the Ridge Forest with a closed canopy is the 

 floor clear enough to give space to a small number of herbaceous species, 

 which are chiefly ferns and the sedges Rynchospora polyphylla and 

 Rynckospora elongata. 



The epiphytic vegetation is not conspicuous, indeed hardly as much 

 so as are the parasitic Loranthacese, although actually embracing a 

 considerable number of species. These are mostly bromeliads and 

 small species of Polypodium and Liparis, while mosses, the hepatic 



