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THE PHILIPPINE 
~ JOURNAL OF SCIENCE 
C. BOTANY 
VoL. V DECEMBER, 1910 No. 6 
PHILIPPINE URTICACEAE. 
By C. B. Rosprnson. 
(From the Botanical Section of the Biological Laboratory, Bureau of Science, 
Manila, P. I.) 
This work was originally undertaken with the purpose of ascertaining 
the relation of the Philippine species of the family to those of other 
countries yielding valuable products for textiles and cordage, but the 
systematic problems proved so numerous that they have had to be entered 
into at length. As a result, the number of species to be credited to the 
Archipelago has had to be greatly increased, and additions have been 
made to the list of genera. Whenever possible, the species have been 
studied in the field as well as in the herbarium; this has been of great 
assistance in the solution of many problems, and the more intensive collect- 
ing thus made necessary has led to the discovery of many additional 
species, while it seems to indicate that similar work in other parts of the 
Islands will bring to light many more. An attempt has been made to 
secure material in considerable quantity, to indicate the variations of the 
species, at least in one locality. Near the conclusion of the work, I have 
had the privilege of examining the entire collection of Urticaceae, obtained 
by Mr. A. D. E. Elmer, on Mount Apo, Mindanao, which contains many 
additions to the species of the family. 
The generic difficulties are of two kinds, systematic and bibliographic. 
The former are often great, reaching their extreme among Philippine 
species between Boehmeria and those species of Pouzolzia having serrate 
leaves. The separation between Pouzolzia and Gonostegia is made on 
characters of much less importance than are used in any other case, but 
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