378 Dar bishire* — Observations on Ma?niilaria elongata. 
surmounted by a set of spines. A single central spine may be separated 
from the marginal spines, which are so numerous as to obscure almost 
entirely from view the body of the plant. A dense mass of hairs is found 
in between the spines. 
The plant is attached to the soil by a rather short and stout root 
(PI. XXV, Fig. 3). 
2. Anatomy. 
I propose now to describe the structure of the main body of the plant- 
shoot, then to discuss the structure of the root, and finally in greater detail 
that of the tubercles and their spines. 
(a) Anatomy of the Stem. 
The specimens which I had the opportunity of examining anatomically 
were not more than about 4-5 cm. in height, and 1*5 cm. in diameter. 
They were obtained from Mr. F. A. Haage, junr., Erfurt, Germany, and 
appeared to be seedlings. 
Disregarding for the present the structure of the projecting warts or 
tubercles, the main body of the shoot-part of the plant consists of a mass 
of fairly uniform parenchymatous ground-tissue, traversed by vascular 
bundles (PI. XXV, Fig. 3). 
The parenchymatous cells measure about 80-120 \x in diameter and in 
cross-section they appear roundish. Of this size they are found near and 
around the vascular bundle, in the cortex, the pith, and the broad medullary 
rays. They may be 380 /a long. Further away from the vascular bundles 
and nearer the epidermis the measurements for the cortical cells would 
be 60 to 70 by 180 to 250 \x. They all contain little cytoplasm, but a large 
nucleus. Intercellular spaces are found very extensively bordering on 
these cells in the cortex. They are, however, very shallow. 
The epidermis, even in older parts of the plants I examined, which 
were themselves however not very old, was not replaced by cork, except in 
cases of injury or in that region where the root joins on to the stem. That 
part of the plant which is exposed to the air and to the light is almost 
entirely covered with the projecting tubercles. The remaining portion 
lower down is in the soil. Stomata are present here and there on this 
buried part, but very possibly they no longer function. Protoplasmic 
contents were not discernible. The radial walls of the epidermal cells are 
wavy and strongly cuticularized. 
As just mentioned, the lower end of the plant frequently develops cork. 
The lower rounded end of the shoot in the plants I examined was covered 
by 6-10 layers of cork. The passage of any adventitious root through the 
ground-tissue of the stem is lined completely with a similar mass of cork. 
Those parts of the lower end of the plant which are actually in contact 
