PHILIPPINE DIPTEROCARPACEAE. 233 
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Pith. — The pith is lieterogeiiouSj the greater part of it being made 
up of thin-wallcd cells. In some cases, miacilaginous cells are found. 
Resin-canals occur either in the center or the periphery of the pith. 
Their number and arrangement has some value as a taxonomic character. 
Wood, — The wood is characterized by the presence of resin-canals and, 
frequently, a large amount of wood parenchyma. The resin-canals do 
not seem to show any very regular arrangement. In some forms (species 
of Pent-acme, Shorea^ Hopea, Parashorea), they are abundant and form 
noticeable whitish rows, which are incompletely concentric and occur at 
irregular intervals. They present a whitish appearance, because of the 
contained resin, and give an appearance like that of seasonal growth 
rings. In some cases (species of Anisoptera and Dipterocarpus) , the 
resin-canals are filled with oil, which causes them to be loss readily 
distinguished. In these cases, the oil flows out and covers the stump 
when the tree is cut, making the stump and the butt of the log very 
gummy. 
In Vatica wood, the resin-canals are much less prominent than'in those 
forms already mentioned. The wood elements are rather finer and 
very regular in arrangement. 
The color of the wood of Vatica and the species of Shorea and Hopea 
which are known as ya-cal or dalindingan, is a yellow-broTO when first 
cut, becoming much darker on exposure to the air. 
Many species of 8horea (S. polysperma, S. teysmanniana, S. negro- 
sensis, etc.) have wood of a fine clear red color. S. squamata, 5. 
eximia and Parashorea pKcata have wood which is much lighter in color, 
but which may occur darker or whicli may darken to the color of S. 
polysperma. It is most often, however, of tlie same color as the sapwood 
of that species. Pentacme coniorla has wood of a dull-gray or faint- 
brownish color. Some Shoreas (S. guiso, etc.) have hard, nne-graincd, 
light grayish or reddish woorl, with a very abundant development of wood- 
parenchyma. 
In all reddish dipterocarp woods the color fades badly on prolonged 
exposure to the air. 
Some species of Anisoptera and, possibly, some Shoreas, which have 
a pale-yellow wood, show a pale-rose tint in the freshly cut wood. 
In hardness, the wood is verj- variable, ranging all the way from the 
very soft wood of Pen-tacme and some of the Shoreas, to the very liara 
wood of some of the Hopeas, Shoreas, and Vaticas. The hardness of 
these latter seems to be due principally to the thick cell-walls. 
The following statement, concerning the minute anatomy of the wood 
are taken from Solereder - "The cross-section of the wood shows rounds 
^Solereder, H. System.-^tische Anatomie der Dieotyledonen (1899) 157. 
