FIBKR STUDIES OF Dll'TlCKOCARPS 99 



ployed in this study were topotypes, while a few are type specimens, 

 ])rt'scrved with botanical material in the Government herbarium at the 

 lUireau of Science in Manila. These were collected mainly from trees 

 Hi.) centimeters or more diameter and came from diti'erent parts of the 

 Archipelago. It is generally conceded that the anatomical structure of 

 wood and consequently its properties are affected by, and vary with, 

 topography and climate and such was found to be the case in Shorea 

 polyspcrma and certain species of Dif^tcrocarpits. Wood of Shorea 

 polyspcniia from we-^tern Luzon, wdiere rainfall is distributed unevenly 

 tliroui;hniu the year and growth conditions are subject to fluctuations, 

 [jrcsenis a striking contrast lo samples of this species coming from the 

 Ivist and South, in regions where the annual rainfall is more evenly 

 distributed. The woods arc darker colored, denser, and less homo- 

 gent.uj; i i contrast lo tho.^e from regions where the growth approaches 

 the optimum. The difference is so striking that it is possible in many 

 instances to determine the arcal origin of a specimen by a superficial 

 examination of the wood. 



In macerating the woods preparatory to fiber examination Schiiltz's 

 solution was used. This consisted in subjecting shreds of woody 

 tissue measuring 2 to 3 mm. in diameter and 12 mm. in length to strong 

 c(nnmcrcial nitric acid in the presence of a few crystals of potassium 

 chlorate. Maceration is permitted to proceed at a temperatu're ranging 

 from •■!■") degrees to 40 degrees C. for about Mo hours. The liquor 

 eventually renders the shreds almost colorless. The acid is then poured 

 off and the material thoroughly washed in several changes of water, 

 care being taken to rinse off all loose fragments. The decolorized 

 shreds are then placed in test tubes which are about -half filled with 

 water and the mixture thoroughly shaken. Sufficient fibrous material 

 for purposes of study is isolated in this way. 



Prior to the study the fibers were stained with a dilute solution of 

 methyline blue and subseciuently transferred to microscopic slid:is. It 

 was found that the ordinary blue ink such as is used in fountain pens 

 offers a satisfactory, temporary stain in place of the more lasting 

 methyline blue. 



Measurements were made of all fusiform non-septate fibers, which 

 in the dipterocarp family consist almost wholly of libriform fibers and 

 tracheids. The tracheids constitute but a small percentag: of the 

 fibrous material, and occur in immediate proximity to the vessels. In 

 contrast to libriform fibers they are abundantly. pitted, shorter, propo ■- 



