3 



the coast and at the altitude mentioned above there is an abrupt change 

 in the character of the vegetation, the bamboo and scrubby thickets for 

 the greater part giving place to the high forest, the transition usually 

 being sharp and well defined. The high forest, commencing at the upper 

 limits of the thickets, extends without a break to the summit of the 

 mountain, although the character of the vegetation at the higher altitudes 

 is very different from that below, not only in constituent species but also 

 in general appearance. In the typical dipterocarp forests on the lower 

 slopes, mosses, lichens, epiphytes, ferns, and herbaceous plants are com- 

 paratively scarce, while the trunks and branches of trees on the exposed, 

 wind-swept ridges above 900 or 1,000 meters are more or less densely 

 covered with many species of mosses and lichens, ferns, orchids, and other 

 epiphytic plants, and the trees themselves are more or less dwarfed, 

 according to their exposure. The ground on these ridges is, for the 

 greater part, densely covered with various species of mosses; herbaceous 

 plants are also more abundant than in the high forests at lower altitudes. 

 In the accompanying paper I have referred to plants found in this loca- 

 tion as growing in the mossy forest on exposed ridges. Few of the species 

 found in this habitat extend downward into the high forest, and. when 

 they do, they are usually found in the deep, damp ravines and canons, 

 and not on the steep slopes. 



ORIGIN OF MATERIAL. 



The material on which the present paper is based has all been collected 

 within the past two and one-half years, and is deposited in the herbarium 

 of this Bureau. It has been received from the following sources : 



Fort st, -,/ Bureau, by direction of Capt. O. P. Ahem, Chief of Bureau. 



Numbers. 



Ahern's collector, Ramos, July-August. 1004...... 98 



Barries, P. T., October, 1903, to April, 1904 313 



Borden, T. E., April. 1004, to May, 1905 1,190 



Leiberg, J. B., July, 1904 ' 100 



Meyer, R., December, 1904, to June, 1905. 435 



Tota] - 2,190 



Bureau of Science. 



Copeland, E. B., mostly ferns and fungi (about) 200 



Elmer, A. 1). E., November, 1904 302 



Merrill, E. D., June, October, 1903; January, 1904- March 



1905 - 575 



YVlutford, H. N., April to July, 1904; December, 1904, to 



May, 1905; September, 1905 892 



TotaI ........... 1,969 



Miscellaneous. 



Topping. D. Le Roy, May, 1904, presented (about) 100 



Aggregate ~±&Vi 



