THE EPIDERMIS AND PERIDERM 69 
of the stigma. The style papille are always smaller, and they 
are of a different form. 
UNICELLULAR NON-GLANDULAR HAIRS 
True plant hairs are tubular outgrowths of the epidermal 
cell, the length of these outgrowths being several times the 
width of the hair. 
The unicellular hairs are common to many plants. The two 
groups of non-glandular unicellular hairs are, first, the solitary; 
and secondly, the clustered hairs. 
Solitary unicellular hairs occur on the leaves of chestnut, 
yerba santa, lobelia, cannabis indica, the fruit of anise, and 
the stem of allspice, senna, and cowage. 
Chestnut hairs (Plate 7, Fig. 1) have smooth yellowish-colored 
walls, and the cell cavity contains reddish-brown tannin. These 
hairs occur solitary or clustered; the clustered hairs normally 
occur on the leaf, but in powdering the drug, individual hairs of 
the cluster become separated or solitary. 
Yerba santa hairs (Plate 7, Fig. 4) are twisted, the lumen or 
cell cavity is very small, and the walls, which are very thick, 
are grayish-white. 
Lobelia hairs (Plate 7, Fig. 5) are very large. The walls 
are grayish-white, and the outer surface extends in the form 
of small elevations which make the hair very rough. The hair 
tapers gradually to a solid point. 
Cannabis indica hairs (Plate 7, Fig. 6) are curved. The 
apex tapers to a point and the base is broad, and it frequently 
contains deposits of calcium carbonate. The walls are grayish- 
white in appearance, and rough. The roughness increases 
toward the apex. 
The hairs of the anise (Plate 7, Fig. 7) are mostly curved; 
the walls are thick, yellowish-white, and the outer surface is 
rough; this is due to the numerous slight centrifugal projections 
of the outer wall. 
Allspice stem hairs (Plate 7, Fig. 2) have smooth walls. 
The cell cavity is reddish-brown. ‘The hair is curved. 
The hair of senna (Plate 7, Fig. 10) is light greenish-yellow 
with rough papillose walls. The hair is usually curved and 
tapering, and it does not have any characteristic cell contents. 
