168 MR. P. GROOM—CONTRIBUTIONS TO THE 
to isolated parenchyma-cells just outside the general scleren- 
chyma-sheath. A few raphide-mucilage sacs occurred all the 
way up the flowering axis. 
Hitherto no reference has been made to some structures which 
occur on the upper parts of the flowering axis, namely certain 
hairs. In the fruiting specimen they are visible merely as 
numerous crushed hairs on the fruit-bearing part of the axis. 
They are entirely absent from the subterranean part of the 
plant, rhizome, or buds. In specimen B their structure can be 
made out. They are glandular hairs coating the upper parts of the 
axis, the ovary, and the perianth-leaves. They secrete mucilage. 
Each hair is composed of a single row of swollen spherical cells. 
Each cell has a large central nucleus slung by thick bridles of 
protoplasm to the general peripheral lining of protoplasm. On 
these bridles minute clear bubbles are visible (mucilage P). 
Histology of the Scales. 
All the scales are more or less closely adpressed to the axis 
which bears them. Thus the lower surface is exposed and the 
upper surface lies against the axis, or axillary bud. 
As there are considerable differences between the structure 
of a bract and of a subterranean leaf, the two will be described 
separately. 
Structure of a Bract (Pl. IV. fig. 4).—At the base of the bract 
the inner (upper) epidermis has relatively thin walls not much 
cuticularized. Some of the cells grow out into secreting hairs. 
The mesophyll is composed of 6-7 layers of parenchymatous 
cells with small collenchymatous thickenings and feebly developed 
intercellular spaces. The layer immediately within the inner 
epidermis is flattened. All the cells composing the mesophyll 
have well-marked nuclei, and in the cytoplasm excessively fine 
deeper-staining filaments are visible. 
The outer (lower) epidermis has walls which are much thicker 
and more heavily cuticularized than the inner epidermis. In these, 
fungal pegs are frequently visible. Some of these cells contain 
hyphe and have brown walls; and in some places the hyphe 
have penetrated to a depth of three layers in the mesophyll, the 
attacked cells having discoloured walls and disorganized contents. 
Towards the margins the scales become thinner, having fewer 
layers of mesophyll; and the inner epidermis acquires more 
thickly cuticularized walls. Most of the cells in these thinner 
