AMKKICAX STOKAX I'k( IDUCTION 19 



THK STRUCTUKK OF THK STORAX-PRODUCIXG WOOD 

 (Legends for illustrations on page 18) 



Fig. 1 — Cross section of wood above girdle. 191S, normal wood; 1919, wood 



formed after girdling, one row of ducts. 

 Fig. L> — Cross section of wood near vertical cut; 1919, wood formed after 



wounding, more than one row of ducts. 

 F'ig. n — Cross section above top horizontal cut. Note abundant ducts. (Small 



dark spots near the bark) and well developed growth ring. 

 Fig. 4 — Cross section below lowest horizontal cut. Note near bottom of pic- 

 ture relatively few ducts and narrow growth ring. Upper portion under 

 uncut bark at side of wound shows more ducts and wood. 

 D, ducts; AR, one year's growth (annual ring); R, ray; P, pore; F, fiber; 

 B, bark; \V, wound beginning to heal over; G, gummy deposit; DC, discolora- 

 tion. 



KI> JLTS OF MlCrWSCOPIC STUDY 



The specimens selected by Dr. Mahood for microscopic study were 

 from typical trees and represented examples of the effects produced 

 by the different types of tapping. They were collected in December, 

 1919, and turned over, in the green condition, to the writer. Although 

 this material was limited in amount, the results from studying it agreed 

 with the average yields of the field tests. Furthermore, they suggested 

 possible improvements in figure operations for storax production. 



Red gum has the typical diffuse-porous type of structure, as shown 

 at "1918 A. R." (figs. 1 and 2). In the wood formed after tapping, 

 abnormal structures from which storax exudes ("D," figs. 1-4) were 

 produced near the wound. These are similar to the induced vertical 

 resin ducts found in turpentined pines." They are not enlarged vessels 

 but intercellular spaces. No horizontal gum ducts were formed. 

 Other structural changes (figs. 1 and 2) were also to be noted in the 

 wood formed after wounding, namely : 



1. The pores tended to become smaller. In the horizontally tapped 

 specimen pores were much fewer than in normal specimens ; in the 

 girdled and vertically tapped specimens they were rather more numer- 

 ous than usual. 



2. The rays appear larger. They may be merely distended, or 

 several may have fused together, or they may actually have added 

 more cells in width. This was particularly noticeable above the girdle 

 in the "deadened" tree. 



' Svendsen, J.I.B., "Ucber den Harzfluss bei den Dieotylen," 190.j 



