THE EPIDERMIS AND PERIDERM 67 
their arrangement, their size, their color, the character of their 
walls, whether rough or smooth, whether branched or non- 
branched, whether curved, twisted, straight, or twisted and 
straight, whether pointed, blunt, or forked. 
FORMS OF HAIRS 
PAPILLZZ 
Papille are epidermal cells which are extended outward in 
the form of small tubular outgrowths. 
Papille occur on the following parts of the plant: flower- 
petals, stigmas, styles, leaves, stems, seeds, and fruits. Papille 
occur on only a few of the medicinal leaves. 
The under surface of both Truxillo (Plate 6, Fig. 3) and 
Huanuca coca have very small papillae. The outermost wall of 
these papilla are much thicker than the side walls. The papill 
of klip buchu (Plate 6, Fig. 4), an adulterant of true buchu, has 
large thick-walled papille. 
The velvety appearance of most flower-petals (Plate 6, 
Figs. 2 and 5) is due to the presence of papilla. The papill 
of flower-petals are very variable. In calendula flowers (Plate 
6, Fig. 1) they are small, yellowish in color, and the outer wall 
is marked with parallel striations which appear as small teeth 
in cross-section. The ray petal papillae of anthemis consist of 
rather large, broad, blunt papillae with slightly striated walls. 
The papillz of the ray petals of the white daisy consist of papillee 
which have medium sized, cone-shaped papille with finely striated 
walls. The papillz of the:flower stigma vary greatly in different 
flowers. In some cases two or more types of papille occur, 
but even in these cases the papille are characteristic of the 
species. 
The papillz differ greatly in the case of the flowers of the 
composite, where two types of flowers are normally present— 
namely, the ray flowers and the disk flowers. 
In all cases observed the papillz of the stigma of the ray 
flowers are always smaller than the papille of the stigma of the 
disk flowers. It would appear from extended obsérvation that 
the papille of the ray flower stigma are being gradually aborted. 
The papille of the style are always different from the papillz 
