120' COrELAJ^D. 
interrupted climbs^ camps were made at altitudes of 1,000, 1,100, 1,600, 
1,800 and 2,400 meters. 
From Mr. Merrill's reports, irom' the size of the rivers flowing from 
the mountain, and from the character of the vegetation of the lower and 
middle altitudes, it is safe to state that Halcon is a very wet mountain, 
more so than any other of approximately equal altitude in the Philippines. 
The party was out forty days, in this time there being more or less rain 
nearly every day, and for one period of thirteen days while they were at 
the higher altitudes they encountered constant heavy rain, day and 
night, and in this time never saw the sun. The moisture conditions 
of the rain-forest — that is, a high humidity essentially uninterrupted 
by any dry season — are thus brought down in sheltered or level places 
to approximately sea-level, and ^^high-forest" conditions are found no- 
where except to a limited extent on the lower ridges, while the savannah- 
"wood seems to be entirely wanting. By virtue of its lesser altitude, this 
lowland rain-forest undoubtedly enjoys an appreciably and constantly 
higher temperature than does the rain forest on Apo ;* for instance at an 
altitude of 1,200 meters, or at San Eamon at an altitude of 700 meters; 
still it has many species in common with both the above localities, and 
F 
its bionomic character, so far as can be judged without a personal visit 
and a study of the fresh plants, is the same. As I have always found 
to be true elsewhere in the world, the temperature plays a most in- 
conspicuous role as compared "with the moisture in determining the 
bionoinic character and the local distribution of plants, and furnishes no 
fit basis for the general classification of faunas or floras. 
Halcon as compared with San Eamon, the locality where the fern 
bionony has been most studied, is notable for the absence of the savannah- 
wood and for the weak development of the high-forest as noted above; 
for the much greater development of the mossy forest, and for the 
presence above this of a moutane brush. Here, as on Mount Apo (it 
is wanting on Mount Malindang), this brush degenerates in places to 
a mere lieath the exceedingly limited vascular flora of which is a curious 
mixture of Australian and north-temperate pioneers. The Pteridophyte 
flora of these two heaths, 450 miles apart, and so far as known isolated by 
that distance, is almost identical. 
MerrilVs Halcon plants, as must be the case with so rich a collection, 
offer a very interesting contribution to our knowledge of the distribution 
of Philippine ferns. In view of the contiguity of Luzon aud Mindoro 
it is but natural that a number of ferns, hitherto known only from the 
mountains of central Luzon^ Maquiling, !Marivclcs, Banajao, etc., or at any 
rate not south of these mountains, should be found here. More consider- 
able southward extensions of range are those of Plagiogyria tnherculata 
and Lycopodium complanatum var. thyoides. Halcon has also some Ma- 
layan plants hitherto known in the Philippines only from northern Luzon, 
such as Saccoloma, Polypodium derrescens and Lycopodium casuarinoides; 
