Figs 8, 9, 12, 15, SEM. Figs 10, 11, 13, 14 Light micrographs. Fig. 8. Transverse section of callus of control wound after 4 weeks. Differentiation of callus into xylem and phloem has occurred. Gum ducts have ceased to produce gum. Xylem present at the time of wounding (OX) and xylem formed after wounding (NX) are visible. Necrotic tissue cutoff by NP is visible at upper right (arrow). X23. Fig. 9. Portion of a stem on side opposite to control wound. Gum ducts (GD) formed in response to inoculated wounds. Gum ducts have begun to coalesce and are still producing gum. X46. Fig. 10. Transverse section through distal edge of control wound after 4 weeks. Strong positive staining for suberin with Sudan Black B is evident. X68. Fig. 11. Transverse section, approximately 3 mm above control wound. After 4 weeks NP has formed distal fingerlike projections surrounding primary phloem fibers. X94. Fig. 12. Transverse section from the midportion of an inoculated wound after 4 weeks. Note the large gum ducts and marked lack of differentiation of callus tissue (CT) compared with control wound (Fig. 8). Hyphae are visible growing along exposed wood surface (arrow) and tissue is generally embedded in a mass of gum (G). X42. Fig. 13. Light micrograph of callus tissue similar to that described in previous figure. Large gum ducts and undifferentiated callus (CT) tissue are visible. X84. Fig. 14. Transverse section of exposed wood in an inoculated wound after 4 weeks. Mat of hyphae is visible growing in gum deposit laong wood surface. X290. Fig. 15. Hyphae of L. persoonii growing in vessel element which was located in the outermost portion of xylem present at the time of wounding and was exposed to the environment at the time of sampling. X433. (Figs. 8 - 15 from Wisniewski et al., 1984).