In kamala (Plate 8, Fig. 3) clusters of seven or more hairs occur; the walls are yellowish, and the cell cavity is reddish-brown. In witch-hazel leaf (Plate 8, Fig. 4) clusters of a variable number of hairs occur. The hairs, which are of various lengths, have yellowish-white, thick, smooth walls, and reddish cell contents.
In althea leaf (Plate 8, Fig. 5) the hairs are nearly straight and the walls are smooth. The basal portions of the hair are strongly pitted.
Branched solitary unicellular hairs occur on the leaves of hesperis matronalis (Plate 7, Fig. 8), and on galphimia glauca (Plate 7, Fig. 9).
The hair of hesperis matronalis has smooth walls, and the two branches grow out nearly parallel to the leaf surface.
The hair of galphimia glauca has rough walls, and the two branches grow upward in a bifurcating manner.
MULTICELLULAR HAIRS
Multicellular hairs are divided into the uniseriate and the multiseriate hairs. Both of these groups are divided into the branched and the non-branched hairs, as follows:
1. Uniseriate.
(A) Non-branched.
(B) Branched.
2. Multiseriate.
(A) Non-branched.
(B) Branched.
Multicellular uniseriate non-branched hairs occur on the leaves of digitalis, Western and Eastern skullcap, peppermint, thyme, yarrow, arnica flowers, and sumac fruit.