INTRODUCTION 35 
the vegetation has suffered enormously in the past century. In 
Blanco’s time it is evident from his own statements that virgin 
forests existed in the immediate vicinity of the town of Angat, 
Bulacan Province, Luzon ; to-day one must travel for many hours 
from Angat before he can find any vestiges of the virgin forest. 
The original vegetation has been destroyed by the primitive prev- 
alent caingin system of agriculture; that is by felling: and 
burning the trees on a selected area, abandoning this area 
after one or two seasons, and clearing another one. The virgin 
forest thus destroyed is replaced by thickets and second-growth 
forests in aspect and in constituent species totally different from 
the original vegetation; by dense bamboo thickets; or by open 
grasslands characterized especially by the dominance of the 
cogon, or lalang grass (Imperata). 
It must be fully realized, in attempting to interpret: Blan- 
co’s species, that the Philippine flora is a very complex one: 
While very many of Blanco’s species are naturally of wide geo- 
graphic distribution, others are very local. It is not sufficient 
to base an interpretation of many of Blanco’s species on a 
specimen labelled “Philippines” as a high percentage of our 
species are strictly local, and very many are known from but a 
single locality. Whenever possible a Blancoan species should be 
interpreted by specimens originating as near as possible to the 
exact place indicated by Blanco, that is, by topotypes. 
In very many cases the native names cited by Blanco and by 
Llanos have furnished the first clue to the identity of their spe- 
cies. This is especially true in those cases where the descriptions 
are very incomplete, and where, due to misinterpretations of 
genera, species were wrongly placed. From the description of 
Rhamnus lando Lianos, for example, while it is evident that it 
applies to no rhamnaceous plant, no botanist would ever suspect 
that a species of Embelia of the Myrsinaceae was intended, and 
I believe that it would have been impossible for any botanist 
properly to interpret the species except for the clue supplied 
by the Tagalog name lando cited by Llanos; material received 
under this name agrees perfectly with Llanos’s description. 
Cases like this are very numerous, and it has thus been possible 
to secure data and material of the very greatest value in con: 
nection with this investigation by prosecuting field work in 
special localities with special reference to the native names of 
plants. Native names are naturally not always used correctly 
by Blanco, and in some cases we have never been able to find 
certain names cited bee him in use; these may now be obsolete. 
