455 
Stiles . — The Podocarpeae . 
on each side of the median one, but yet distinctly underneath the phloem. 
These canals are small, but the epithelial cells seem to be of the normal type. 1 
A sclerenchymatous hypodermal layer is developed beneath the epi- 
dermis on the upper side. On the lower side this layer is only developed 
below the midrib, and even on the upper surface it is discontinuous. At 
the base of the leaf, however, hypoderm is developed all round. Stomata 
seem almost entirely limited to the under side of the leaf. They are sunk 
below the surface, as is usual in Coni ferae, and are of the usual Coniferous 
type. There is a well-marked palisade layer below the upper epidermis 
and hypoderm ; the remaining mesophyll of the leaf is well provided with 
intercellular spaces. It is in this £ spongy ’ tissue that the accessory 
transfusion tissue is found. 
The structure of the leaves of Podocarpus elatus and P. polystachyus 
seems to be essentially similar. In these species three resin canals beneath 
the phloem appear to be the rule. There are slight differences in the 
quantity of transfusion tissue, accessory transfusion tissue, and sclerenchyma, 
but no doubt the quantity of these is to some extent determined by external 
conditions. It is interesting to note that the leaves in which this type of 
structure has been observed are amongst the largest of the uninerved ones 
in the genus. 
In leaves referred to Podocarpus amarus , obtained from the Royal 
Gardens, Kew, there are three resin canals, as in P. macrophyllus , but they 
are smaller than usual in this type, and are easily overlooked. 
2. Podocarpus vitiensis, comprising Bertrand’s monotypic subgenus 
Polypodiopsisp according to that author has leaves characterized by a structure 
different from that found in other species in the genus. The chief difference 
consists in the distribution of the resin canals, one under the nerve and one 
in the parenchyma on each side of the leaf and near the margin. The 
decussate arrangement of the leaves and other characteristics given by 
Bertrand are also found in other species. 
3. In the third type of leaf there is normally a single resin duct under 
the vascular bundle, as, for example, in P. salignus (Text-fig. 2, b). There 
is also a tendency towards reduction of accessory transfusion tissue and 
sclerenchyma as compared with the P. macrophyllus type. In P. Totara 
the accessory transfusion tissue is not very typical, the cells being rather 
short, and not much lignified, intermediate in character between the meso- 
phyll cells and typical accessory transfusion tissue. Stomata were observed 
on the lower surface only, while a sclerenchymatous hypoderm was observed 
on both sides. Podocarpus elongatus appears to have leaves with a similar 
internal structure, but here, as Bertrand 3 correctly observed, stomata are 
1 Pilger (’03, p. 8) records the frequent presence of three resin canals under the bundle in 
Podocarpus, but does not give the names of any species. 
2 Bertrand (’74), p, 66. 
H h 2 
3 1. c., p. 60. 
