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THE FLOUA OF MOUNT IIALOON. 253 
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considered by Dr. E. B. Copdand under the title Pteridophyta IlaJco- 
nenses,^ 20G species and varieties being represented in the collection, of 
which twenty were described as new^ and eight reported for the first 
► time horn the Archipelago. Of the OrcJiidacew of the Ilalcon area, 
101 species are known of which about 42 are new. These Avcre all sent 
to Mr. Oalces Ames and are considered by him in a following paper. 
Tlie mosses collected on tlie expedition have been enumerated by V. F. 
Brotherus, Helsingfors, Finland, his paper also following this one. No 
attempt has been made to determine the rather extensive collections of 
scale-mosses, lichens and fungi collected on the expedition, but it is hoped 
that arrangements can be perfected with various specialists which will 
result in having these groups considered at a later date. Nearly all the 
other material collected by Mr. Merritt and myself has been discussed 
in the present paper, but in one or two families, scantily represented 
on Halcon, specific identifications have not been made for one reason or 
. another, and at least three species are not mentioned in this paper, the 
material representing them being insufficient to refer them with certainty 
to their respective genera, 
Ilalcon is perhaps the most humid mountain in the Philippines, 
the rainy season continuing: practically for nine months of the year, 
from May to January, without interruption, while the remaining three 
months are by no means free from precipitation, as we know from 
Lieutenant Lee's experience in the vicinity of Halcpn in April, 1904. 
The enormous amount of rain in the Halcon area is shown by the rela- 
tively very large rivers flowing from the range. Although these in the 
maximum are not more than 25 or 30 miles in length, and perhaps they 
may be shorter, they have a breadth of from 100 to 300 yards in their 
lower parts, and a constant flow of a large volume of water. In the 
rainy season the volume of the latter is greatly augmented, all the rivers 
being subject to sudden and enormous floods, as is shown by the expe- 
rience of Whitehead, Lee and our own party. Whitehead recorded that 
the Catuyran Kiver, 200 yards wide at the place where his camp was 
located, rose over 20 feet within a period of less tbin twelve hours. 
Epiphytic orchids, ferns and other plants, mosses, lichens, etc., which in 
other parts of the Pliilippines are usually found only at considerable alti- 
tudes above the sea, are in the vicinity of Halcon encountered at compara- 
tively low elevations, along tbe Alag and Binabay Kivers, Go to 200 meters 
above sea level, and along the Baco River at ai)proximatcly sea level, 
thus showing that the relatively high humidity is not confined to Halcon 
itself but affects the surrounding low country to a considerable extent. 
As a result of this high himiidity the open grass lands and savannah 
forests are entirely wanting on the north side of the Halcon Range, 
^This Journal, Sec. €, Bof. (1907), 2, 119-151. 
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