702 PROFESSOR W. C. WILLIAMSON ON THE ORGANIZATION 
Plate LV. fig. 35 B. A second transverse section made higher up in the petiole, dis- 
playing the same arrangements as the last, but with two ternary 
bundles (x, x) removed further away from the secondary ones 
(aa, aa), enlarged 5 diameters. 
„ fig. 35 C. A third transverse section of the same made still higher up, and 
with the left-hand ternary bundle (x") clearly defined, enlarged 5 
diameters. 
Plate LVI. fig. 35 D. The fourth section, with lines of prosenchymatous cells (k) ar- 
ranged in three divergent lines, and indicating the approaching 
separation of the petiole into four parts, viz. a primary, two 
secondary, and one ternary petiole, enlarged 5 diameters. 
„ fig. 35 E. The fifth section, in which the ternary branch (35 D, x") has disap- 
peared, and the two secondary ones (y, y ) are further enlarged 
preparatory to becoming similarly detached. 
Plate LV. fig. 35 F. Lowermost of a series of transverse sections of a secondary 
petiole, with its central crescentic bundle at aa ; a ternary bundle 
(x) is proceeding outwards from one side of the petiole, and a 
second one is being given off at x', in the opposite direction from 
the opposite horn of the crescent ; enlarged 8 diameters. 
Plate LVI. fig. 35 G. A second section made a little above the last, with the upper 
ternary bundle (x') moving outwards towards the periphery, 
enlarged 8 diameters. 
„ fig. 35 H. The ternary bundle of figure 35 F), from a section intermediate 
between F and G, and now become an independent ternary 
rachis, enlarged 8 diameters. 
„ fig. 35 I. A yet higher section than fig. 35 G, with the ternary bundle (x 1 ) 
displaying a quaternary branch (x 1 "), and a new bundle being 
separated at x" from the central crescent for liberation in the 
upward direction, enlarged 8 diameters. 
„ fig. 35 K. A still higher transverse section, in which the ternary bundle ( x' 
of fig. 35 I) no longer appears, it having become detached as the 
centre of an independent rachis, similarly, though in the opposite 
direction, to that in which the bundle x became detached from 
fig. 35 F. A new bundle is now preparing to be given off from 
35 K, x" in the same direction as 35 F, x. Enlarged 8 diameters. 
Plate LIV. fig. 36. Portion of a vertical section of the middle bark (fig. 29, h), mag- 
nified 80 diameters. 
Plate LV. fig. 37. Oblong cells of a vertical section of the outermost portion of the 
middle bark (h), passing into the prosenchymatous form of the 
outermost layer (k), magnified 80 diameters. 
„ fig. 38. Prosenchymatous cells of the outermost bark, from a vertical 
section, magnified 80 diameters. 
