TO BirD’s-EYE FORMATION IN THE WooD OF TREES, 35 
FiG. 5.—Section radial longitudinal to both stem and root. 
F1G. 6.—Longitudinal section of papilla caused by medullary-ray root. 
FIG. 7.—Rhizogenous medullary-ray as seen in transverse section of stem. 
Fic. 8. tics oss of rhizogenous medullary-ray through cambium of 
mother stem 
FIG. sige cylinder of rhizogenous medullary-ray root in transverse 
section. 
FIG. 1 sae saa as section of rhizogenous medullary-ray root showing 
axis cylinder and corte 
FiG. 11.—Section ae tangential to wood-body of stem showing 
rhizogenous medullary ray in transverse section. 
FIG. 12,—Twig showing adventitious roots. 
Fic, 13.—Cufpressus gigantea. Section transverse to stem and longitu- 
dinal radial to medullary-ray root. 
PLATE IX. 
FIGs. 14-25._-Maple tree. 
F1G. 14,—Tree showing numerous adventitious roots. ; 
FIG. 15.—Part of a limb of the tree seen in Fig. 14 on nearer view. 
FIG. 16-17.—Portion of two other trees showing adventitious roots. 
Fic. 18.—Portion of stem in Fig. 17 enlarged. 
FIG. 19.—Root cluster with portion cut away to show appearance of the 
wood. 
FIGS. 20, 21, and 22.—Cylinders extracted by means of Pressler’s Incre- 
ment Borer to show connection of root with parent stem. 
Fics. 23 and 24.—Young adventitious roots in longitudinal section. 
Fic. 25.—Passage of rhizogenous medullary-ray through wood body, 
cambium and bark of parent stem. 
PLATE X. 
FIGs, 26-30.— Maple tree. 
Fic. 26.—Median longitudinal section of adventitious root. 
Fic. 27.—Part of Fig. 26 enlarged. 
Fic. 28.—Transverse section near base of adventitious root. 
F1G. 29.—Cork layer forming across base of old adventitious root. 
FIG. 30.—Transverse section near apex of adventitious root. 
Fics. 31-38.—Apple tree. 
F1G. 31.—Branches producing coral-like clusters of adventitious roots. 
Fics. 32 and 33.—Twig which was first inverted so that adventitious roots 
first grew down towards the tip (Fig. 33). On being reinverted adventitious 
roots again show positive geotropic curvature (Fig. 32). 
