The stone cells of winter’s bark (Plate 32, Fig. 2) vary from elongated to nearly isodiametric. The pores are very large, the light yellowish wall is irregularly thickened, and the central cavity is very large. The pores are prominent.
PLATE 31
Branched Stone Cells
1. Tea leaf (Thea sinensis, L.).
2. Witch-hazel bark (Hamamelis virginiana, L.).
3. Hemlock bark (Tsuga canadensis, [L.] Carr).
4. Wild-cherry bark (Prunus serotina, Ehrh.).
The stone cell of bitter root (Plate 32, Fig. 3) is nearly isodiametric. The walls are yellowish white and strongly porous and striated. The central cavity is about equal to the thickness of the walls.
The stone cell of allspice (Plate 32, Fig. 4) is mostly rounded in form, and when the outer wall only is in focus it shows numerous round and elongated pores. The central cavity is filled with masses of reddish-brown tannin. The striations are very prominent.
The diagnostic stone cell of aconite (Plate 32, Fig. 5) is rectangular or square in outline; the walls are yellowish and the central cavity has a diameter many times the thickness of the wall. The side and surface view of the pores is prominent, and the striations are very fine.
POROUS AND NON-STRIATED STONE CELLS
Porous and non-striated stone cells occur in Ceylon cinnamon, in calumba root, in dogwood bark, in cubeb, and in echinacea root.
The diagnostic stone cells of Ceylon cinnamon (Plate 33, Fig. 1) are nearly square in outline; the walls are strongly porous and the large central cavity frequently contains starch.