ANATOMY OF THE ROOTS OF PALMS. 479 
(48) PrycnosrERwA MacanTHURI, H. Wendl. 
The cortical tissues are very similar to those in P. perbreris. The central cylinder is 
very greatly broken up as in Kenia, but there is still more strongly marked inrolling of 
the separate ares. Internal fibrous strands are present, but are few in number. Each 
contains a central vessel, in one case aceompanied by a phloem-group. The medullary 
and cortical tissues are quite continuous, and similar bundles of fibres are present 
in each. 
(49) PrYcHOSPERMA FILIFERA, H. Wendl. 
The limiting-layer is, as usual, composed of isodiametrie cells with thin lignified 
walls. This is followed by a narrow zone of elongated cells with slightly lignified walls 
and dark mucilaginous contents. In the parenchymatous cortex occur bundles of 
fibres and air-spaces. The endodermis is of the usual lignified type; the pericycle is 
one cell thick. 
In a small root all the elements of the fibrous zone are not yet lignified. The pith is 
represented by a few parenchymatous cells. A very great tendency to V-formation 
obtains in this root. Out of fourteen protoxylem-groups twelve are arranged as V's with 
six internal larger vessels. The other two groups, which occur at either end of a 
diameter of the cylinder, are in conjunction each with its own large vessel. It is 
impossible to say whether this diametrical arrangement has any morphological signifi- 
cance, since the orientation with regard to the stem could not be determined. 
In a larger root a considerable pith occupies the centre and is surrounded by a 
comparatively narrow fibrous zone. Here again V-formation is very strongly marked. 
'This root differs from all other palm-roots examined in the fact that to each protoxylem- 
group there is a considerable number (often four or five) of larger vessels, two of which 
are often placed tangentially. In some cases three of these groups may join tangentially, 
producing a xylem-band connected externally with three protoxylem-groups. Such a 
formation is usually followed laterally by V's with extensive internal xylem-groups, and 
in this way a nearly complete xylem-ring may be formed with exarch protoxylem-groups 
between which lie the rounded phloem-masses. 
The pith contains bundles of lignified elements, in transverse section looking very 
much like fibres, but seen in longitudinal section to be short and square-ended. Two 
groups of fibrous tissue, each enclosing one large and several smaller vessels, oceur in the 
pith. In these large roots the contour of the cylinder is slightly lobed, but no complete 
gap was observed. 
(50) PrxcHuosPERMA CuNNINGHAMIANA, H. Wendl. 
The limiting-layer is as normal, and is followed by the usual small elongated 
elements, and these again by a parenchymatous cortex through which run lignified 
fibrous elements, but no definite fibrous bundles. The inner part of this cortex has fairly 
regulariy developed air-spaces, and here there is a tendency to grouping of the fibres into 
bundles. The endodermis is of the usual lignified type. The pericycle is generally one 
cell thick, but occasionally it is doubled. ‘There is à well-developed fibrous sone in which 
the xylem and phloem are embedded. V-formation is not infrequent. An interesting 
