356 MISS HILDA M. CUNNINGTON ON THE 
of which arises in the axil of a ventral leaf. The axillary buds of ZEnAalus rarely 
develop into vegetative shoots, though it does happen sometimes; those that do develop 
usually give rise to inflorescence-peduncles. 
In Hooker's ‘Flora of British India,’ p. 663, Knhalus is described as being monecious 
or dicecious. The inflorescences arise in the axils of dorsal leaves, and each is enclosed 
in two spathe-like bracts. The male inflorescence consists of a number of small flowers 
on a conical “ receptacle." The female inflorescence consists of one flower only. 
THE Ruizowr. 
In his account of the various parts of Enhalus acoroides, Chatin gives a brief descrip- 
tion of the rhizome; but the stem described by him was not that of Enhalus, and 
Magnus, in 1870, suggests that it was probably Posidonia. The latter describes the 
stem as possessing a large central bundle surrounded by dense large-celled parenchyma. 
Svedelius (1904) briefly describes the anatomy of the rhizome. He states that it has 
a large cortex, the external layers of which have cutinized cell-walls and are devoid of 
cell-contents, and within them there are cells with large starch-grains. He describes 
the endodermis as devoid of starch-grains and without thickened walls, the vascular 
system as slightly developed, the wood-vessels as being few and not lignified, and he 
notes the tannin-cells, abundant within the stele, but more scattered in the cortex. 
As the descriptions of Magnus and Svedelius show inaccuracies and omissions, an 
account of the anatomy follows here. 
The Rhizome Anatomy. 
The surface of the stem is so closely crowded with leaves and leaf-scars, that the 
distinction into nodes and internodes is obliterated. Hence the epidermis is reduced to 
irregular interrupted bands and to the region of the actual apex. In the older parts 
where the leaves have decayed, leaving bristles only, about eight of the outermost 
layers of the cortex become devoid of contents, and their walls become infiltrated with a 
dark brown pigment. These walls are not cutinized, for they give the cellulose reaction 
with iodine and sulphuric acid. 
A wide layer of living cortex consisting of parenehyma-cells containing large starch- 
grains lies within these dead cells. These increase and then decrease in size from the 
outside inwards. In the dead peripheral cells the intercellular spaces are minute, but in 
the living cortex they gradually increase in size and then decrease again in passing from 
the periphery to the stele. In the stem there are no intercellular spaces at all 
comparable in size or structure with the lacunz of the root, leaf, or inflorescence 
peduncles. Interspersed among the cortical parenchyma-cells, elongated pigment-cells 
run parallel to the direction of the axis. These, Svedelius describes as tannin-cells; 
but it was impossible to test the substance, as the material had been transported 
in alcohol containing iron. It stains deeply with various dyes (methyl-blue, safranin, 
hæmatoxylin, iodine-green, and eosin), but not with alkannin dissolved in 50 °/, alcobol. 
It is insoluble in absolute alcohol, xylol, and water. 
