56 SIR DIETRICH BRANDIS—AN ENUMERATION 
vascular bundle. At the top, below the blade, the 2 lateral ducts 
have bifurcated and the central mass has changed its shape 
(fig. 14). In the midrib near the base of leaf (fig. 15) the 3 
vascular bundles have united and form a semicircle containing 
5 resin-ducts, with a bend below, closed on the upperside by a 
belt of bast which forms a closed ring all round, and bands of 
xylem and phloém. Hopea Pierrei, Hance, has a similar structure. 
H Mengarawan, however, has at the base 5 resin-duets in 3 
distinct vascular bundles, and at the top of the petiole the central 
mass contains 3 resin-ducts. 
The species belonging to the other two sections of the genus, 
Petalandra and Euhopea, have, so far as known, that in common 
with H. cernua and allied species, that the lateral leaf-traces 
have only a very short transit in the bark; they differ, however, 
in this, that the apical resin-duct divides itself into 2 branches 
only, one destined for the apical leaf-trace, the other for the 
axillary bud. As regards the number of resin-ducts at the base 
of the internode, H. fagifolia, Miq., Recopet, Pierre, dealbata, 
Hance, oblongifolia, Dyer, according to Pierre, H. odorata, Roxb., 
and glabra, W. et A., according to my observations, have from 
8-12 resin-ducts in the pith at the base of the internode: 
H. ferrea, Pierre, however, has only 4. It should be added that 
the resin-ducts at the base of the internode in A. cernua, Pierret, 
and Mengarawan are remarkable for their uniformly large dia- 
meter, as compared with the other species, in which the ducts 
are often very unequal in width. 
As regards the petiole, fig. 16 gives that of H. odorata below 
the blade as an example. The main point is, that the outer 
semicircle consists of a somewhat larger number of vascular 
bundles and resin-ducts than in Dryobalanoides ; they vary from 
5 to 9, and in some species there is in addition a duct in the 
central mass. 
Undoubtedly, as regards internode and petiole, the species of 
sections Petalandra and Euhopea are similar to many species of 
Shorea and, barring the mucilage-cavities, also to the species of 
Doona. This circumstance has induced Burck to limit the genus 
Hopea to the species which agree with H. cernua in structure, 
and to transfer all others to Doona, including Hopea odorata, the 
species upon which Roxburgh founded the genus. This change, 
however, cannot be maintained. Apart from the mucilage-ducts 
in pith and cortex, Doona has in the structure of flowers, fruit, 
