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maps of Bataan Province one finds such combinations as “Parang de 
Culis” (AMemecylon edule) or “Parang de Ligaa’” (Zizyphus) and others. 
I can do no better than use this word “parang” as a general term for the 
types of vegetation about to be discussed, no matter what their origin, and 
to distinguish one type of parang from another by the generic name of the 
principal or characteristic species. In caingins which have been aban- 
doned for long periods the invading vegetation often simulates that of 
the parang to such an extent that at times it is difficult to distinguish 
its origin. However, in the parang proper exotic species are rarely 
present, and if present, never predominate. 
The laws controlling the invasion of plants into new habitats or into 
old modified ones, have long been recognized and are more or less clearly 
defined.** It must be remembered that the types of vegetation which 
are now to be discussed are only stages in the return to a climax formation 
similar to the Bambusa-Parkia formation, which has already been de- 
scribed. 
Parangs.—The process of reducing the forest may be arrested at any 
of its stages. Usually, the original growth is not taken away at one time. 
If the bamboo is sought, its removal leaves large, open places between the 
dicotyledinous trees, but all the culms are usually not taken, and even if 
they are, the food supply stored in the cxspitose bases would enable the 
clumps to recover their normal condition so quickly that the short 
respite granted the undergrowth does not enable it to gain much headway. 
However, repeated and frequent cuttings have a tendency to thin out 
the bamboo growth, for with a reduction of the photosynthetic surface, 
less nutritive material is stored in the underground parts, and thus 
shoots may be removed faster than new material can be elaborated to 
replace the stored-up food. In this way clumps may be entirely reduced, 
or at least so much thinned that other vegetation will have a better 
opportunity to compete. The result is that many species which before 
were poorly developed, at once spring into prominence. Trees, shrubs, 
and lianas which were present in the original forest then give character 
to the vegetation. Of course, if any of these are removed with the 
bamboo, they, like the bamboo, are not in situ to compete with the exist- 
ing vegetation. The character of the new vegetation will partake of that 
of the old, minus the species removed. 
Dinochloa Parang.—One of the lianas found scattered in the original 
forest of the Bambusa-Parkia formation is Dinochloa diffusa, itself a 
bamboo, with a habit of growth which makes it peculiarly fitted to spread 
into the open places made in the forests. Where supports are present, 
like other lianas, it presents most of its foliage in the top of the forma- 
tion. The stem may branch at long intervals. These branches may 
* See Clements, F. E., Research Methods in Ecology, 265, for a statement of 
the laws of invasion of plants into clearings; also Whitford, H. N., The Forests 
of the Flathead Valley, Montana, Bot Gaz. (1905) 39: 282-283. 
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