Comparative Anatomy of the Casuarineae . 235 
sisting of three or four cells with thickened walls, arises from 
the epidermal cells at the base of the furrow. If the epidermis 
lining the furrow were removed and laid out flat, one would 
see a row of hairs down the centre with three to four rows of 
stomata on either side. The function of the hairs is evidently 
to protect the stomata and to diminish transpiration. The 
slight hairiness of the stem of many species is due to the 
projection of these hairs beyond the opening of the furrow. 
In the square-stemmed species described by Poisson, where 
no furrows occur, the stomata are placed in long longitudinal 
rows, at more or less frequent intervals round the stem. 
Thus, except for being slightly more depressed, the stomata 
of these species entirely miss the protection of the furrow and 
the hairs. 
On macerating a piece of stem in Schultze’s mixture, the 
cuticle splits at the line of insertion of the hairs, and so peels 
off in strips. Immediately below the epidermis, in a transverse 
section, there is a narrow band of sclerenchyma, which in some 
species (e.g. C. glanc a, Sieb. and C. torulosa , Ait.) is prolonged 
into a conspicuous ridge, penetrating the palisade-tissue, and 
occasionally extending so far as to divide the latter into two 
portions. The chlorophyll-tissue, consisting of palisade-cells, 
is restricted to the ridges, and is formed of two or three 
layers of radially-elongated cells. This tissue is bounded on 
the inner side by a rather indefinite parenchymatous layer, 
which, by the conspicuous suberization of the radial walls of 
most of its cells, proves to be an endodermis. By reference 
to Figs. 1 , 2 , and 4 , it will be seen to have a sinuous course, 
coming close to the surface beneath the furrows and curving 
inwards beneath the palisade-tissue so as to touch the cortical 
bundles. 
There is one cortical bundle opposite each ridge of the 
stem, only separated from the palisade by the endodermis. 
Each cortical bundle is very small, its xylem being represented 
by only a few spiral elements ; the phloem, on the other hand, 
being considerably larger, and extended on either side along 
the face of the palisade, thus tending to give the bundle 
