478 DR. ERIC DRABBLE ON THE 
(46) Crrrostacuys RENDA, Blume. 
The limiting and subjacent layers are of the usual type, and are followed by a closely 
packed parenchyma with mucilage-canals, and this again by the loose layers of the 
cortex, with their air-spaces and bundles of fibres, which are shorter than usual, and 
belong rather to the Kentia-type than to the more elongated, narrow type of Oreodoxa 
and Raphia. Individual elements of the same nature occur in the zone immediately 
surrounding the endodermis. The endodermis is lignified, and is followed by a one- or 
two-layered pericycle. | 
The fibrous zone of the central cylinder is broad, and generally each protoxylem-group 
has its own one, two, three, or more large internal vessels. Some of the protoxylem- 
groups are, however, without internal vessels. V-formation is not well shown. The 
central medulla possesses fibrous bundles and air-spaces like those of the cortex. Three 
or four bays of fibrous tissue project into the pith, and nearly form free medullary 
strands. 
Tn large roots the fibrous zone is incomplete on one side, and the incurved edges are 
followed by the endodermis more deeply than usual; the endodermis is, however, finally 
lost in the common ground-tissue. 
An interesting feature in this root is the occurrence of two strongly inwardly 
projecting bays of fibrous tissue in which the protoxylem is well developed internally 
and accompanied laterally on one side by a phloem-group (text-fig. 19). 
LI 
In other eases this internal xylem is disappearing, the smaller elements having quite 
aborted, leaving only the small metaxylem-group abutting on the large internal vessel. 
In other cases, again, only the large internal vessel persists, Thus some of the large 
internal vessels of these roots undoubtedly represent the remains of what were originally 
inwardly directed xylem-groups. 
(47) PrycHosPERMA PERBREVIS, H. Wendl. 
Immediately beneath the normal limiting-layer is a zone of three or four fibrous 
elements lignified and thickened and with transverse walls. Then follows a zone of 
extremely densely thickened and pitted fibres. Theinner cortex is parenchymatous, and 
is provided with definite bundles of fibres with small lumina and also with some less 
thickened fibres generally running singly. In the internal portion of this cortex are 
 air-spaces. Through this region run ducts, containing much mucilage and some crystals 
of calcium oxalate. The endodermis is of the usual thickened and lignified type. The 
central cylinder is normal and uninterrupted ; a broad zone of parenchyma contains the 
xylem and phloem peripherally. Only one ring of large internal vessels is present. 
geg — there is a — pith containing some lignified elements. 
