414 DR. ERIC DRABBLE ON THE 
the sclerenchymatous zone is interrupted on one side, and into this gap the endodermis 
dips, being continuous round the inrolled margins of the sides of the gap, but lost 
internally, the cortical and medullary ground-tissue being quite continuous. 
(49) HETEROSPATHE ELATA, Scheff. 
The limiting and subjacent layers are of the usual type. The parenchymatous cortex 
has large air-spaces, and in the external layers of the inner cortex are lignified elements of 
two kinds—rows of lignified parenchyma and true fibres. In the internal layers the 
fibres occur in bundles. The endodermis is typically lignified. The non-lignified 
pericycle is one-layered. Thexylem and phloem are embedded in a fibrous zone. The 
large vessels extend for a greater distance internally than usual, as do also the phloem- 
groups. Xylem and phloem V's of a type similar to those in Caryota Rumphiana, 
Mart., are formed. In somewhat larger roots the central cylinder is lobed. Opposite the 
depressions the arrangement of xylem- and phloem-groups is peculiar (see text-fig. 15). 
There are no completely free medullary strands, but many strands attached laterally to 
the fibrous zone project into the medulla, each strand having its central vessel. Some 
fibres occur in the pith, with tendency to arrangement into bundles. 
In still larger roots the cylinder is completely broken up into lobes. The endodermis 
dips into the spaces between the lobes and there loses its identity. Bundles of fibres are 
well developed in the medullary parenchyma of these roots. 
(43) ONCOSPERMA FASCICULATUM, Thw. 
The parenchymatous cortex has small, very irregular air-spaces arranged in many zones, 
and bundles of fibres of the larger less densely lignified type, not arranged into definite 
strands bounded by stegmata such as we find in many roots, but agreeing closely with 
those found in Kentia sp. (g.v.). The endodermis is lignified ; the pericycle one-layered. 
The xylem and phloem lie in a rather broad fibrous zone; V-formation occurs 
occasionally, but is not general. Many of the protoxylem-groups are without internal 
large vessels. In one V the xylem-groups instead of converging to the outer portion of 
the large vessel, as is usually the case, converge to the sides. (Text-fig. 16.) 
Fig. 16. 
a 
[e] 
The central medulla contains some irregular air-spaces. 
