313 
are still enclosed by the older ones. the hairs are directed upwards 
or adpressed, but after exposure they point downwards; those on 
the blade are at right angles to the leaf surface. (Plate IL.) 
“ The hairs, which are hyaline and unicellular, are of two.types, 
one with a blunt or rounded apex, the other being sharp pointed 
(fig. i A and C). In both types the base of the hair is 
embedded in a cushion or rosette (fig. i B). The blunt hairs 
are more numerous than the others on the young sheaths whilst 
on the older ones only pointed hairs are found. At the first the 
pointed, hairs are on the whole not quite so long as the. blunt 
hairs which measure 1-15mm., but later they slightly exceed 
them. In the young stage the two types of hairs cannot be 
distinguished, but when mature, so far as can be ascertained, they 
are distinct. In all the blunt hairs a constriction of the wall 
occurs near the base, giving the latter a somewhat bulbous form. 
the wall being thinner below the constriction (fig. iv). The 
pointed hairs may or may not have a bulbous base (figs, ii and iii), 
and in the latter ease the base is less deeply’ embedded (fig. i C). 
“The apices of the hairs of these two types are distinct, the 
wall of the. pointed hairs being thickened so. that the lumen is 
obliterated for some distance from the top, while the apex of the 
lunt hairs is swollen and ends in a small knob. In fig. v is 
depicted the apex of a mature blunt hair. In the lower part is 
seen the thick cell wall E, and lumen with content F. Higher 
up the contents and the wall, except for an outer sheathing layer C, 
become merged. into. a granular mass, above this a more homo- 
geneous part A is seen which resembles the cork of a bottle whose 
neck is. formed by the wall C. At. this stage the structure can be 
determined by staining with Schultz’s solution 
“ The ‘ cork’ or plug is stained a cellulose blue, it has a clear 
blue outer layer B, and from its appearance is mucilaginous ; 
while the wall © stains yellow, and the mass D passes from blue 
at the top to yellow below. The cell wall lower down E, is,yellow 
except for the innermost layer which is blue. At the base of the 
hair where the wall is thin (fig. iv) a blue colour is obtained. 
“ The reactions of the pointed hairs to stains agree with those 
of the blunt hairs, the base staining yellow and the apex blue with 
Schultz’s solution. | ge 
_ “The wall is not lignified in either type of hair. With iodine 
it stains. yellow throughout, and on the addition, of sulphuric acid 
the inner layer becomes blue and thus appears to consist of cellulose. 
' With ferric chloride the lower and outer parts of the wall were 
Stained red-brown. With the xanthoproteie reaction, an orange 
colour was obtained in the walls from the base up to % of the 
length of the hair, and the same part was stained red with Millon’s 
reagent. This reaction must be due to some infiltrating substance, 
the nature of which has not been determined. 
“On treating a mature hair (fig. vi) with concentrated 
Sulphuric acid and also by staining with Sudan III there is found 
to be a layer of cutin on the outside, this was not observed below 
