OF THE DIPTEROCARPACE Z. 145 
EXPLANATION OF THE PLATES. 
Pare I. 
Figs. 1-6. Dryobalanops lanceolata, Burck. (All figures magnified 10 times, 
except 6, which is magnified 17 times: Herb. Regium Berolinense.) The 
place where sections 1-5 are taken is indicated on fig. 17. 
Fig. 1. Base of internode, above insertion of side branch, still attached to the 
main axis. The main axis has one resin-dut in the pith, and 2 
lateral leaf-traces in process of separation from the main cylinder, 
each with a resin-duct in the pith. 
Fig. 2. Higher up in internode. The resin-duct in the pith has bifurcated, 
the main duct remaining in the centre, while the branch duct is 
nearer the apex of the pith. The lateral leaf-traces have separated 
entirely from the central cylinder and are now in the cortex. 
Fig. 3. About the middle of internode. The branch duct has bifurcated, one 
branch being in the apex of the pith, in the apical leaf-trace which is 
in process of formation, the other branch is destined for the axillary 
bud. The main duct has also bifurcated, not, however, in the direction 
of the main axis of the pith, but at right angles to it. 
Fig. 4. Below the insertion of the petiole. Two lateral branches of the main 
duct in the pith are approaching the wood, the medullary rays at this 
point arranging themselves in a fan-shaped fashion. These lateral 
ducts are destined to enter the iateral leaf-traces in the next higher 
internode. 
Fig. 5. Petiole formed of the apical and the 2 lateral leaf-traces, the 2 lateral 
resin-ducts have bifurcated. The lateral resin-ducts intended for the 
next higher internode are entering the wood. 
Fig. 6. Petiole detached from the branch. The central intricate mass of 
vascular bundles has 5 resin-ducts, 2 of which are on the outside edge 
of the central mass. 
Figs. 7-9. Hopea cernua, Teysm. et Binn. (All figures magnified 15 times: 
Herb. Brandis.) 
Fig. 7. Section of an internode 28 mm. long, 8 mm. under insertion of petiole, 
3 large resin-ducts in circumference of pith at the 3 corners of a 
triangle, the apical duct intended for the apical leaf-trace, the 2 
lateral for the 2 lateral leaf-traces. A 4th duct on the 3rd concave 
side destined for the apical leaf-trace of the next higher internode. 
Fig. 8. Section, 4 mm. under insertion of petiole. The 2 lateral ducts have 
bifurcated and the branch ducts have entered the wood. 
Fig. 9. Section immediately under insertion of petiole. Two lateral leaf- 
traces in the bark, each with a resin-duct in pith. The apical duct 
has subdivided into 5 branches, the 2 lower being destined for the 
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LINN. JOURN.—BOTANY, VOL. XXXI. 
