Histology of medicinal plantsMansfield, William James
Science
Histology of medicinal plants
Mansfield, William James
Botany, Medical; Plant anatomy
The hairs on cumin fruit vary considerably in size. All the hairs
are spreading at the base and blunt or rounded at the apex. The
cells forming the hair are narrow and the walls are thick. Three
differently sized hairs are shown in Plate 10, Fig. 1.
The hairs of the base of the ligulate petals of calendula (Plate 10,
Fig. 2) are biseriate. The hairs are very long and the walls are very
thin.
=Multicellular uniseriate branched hairs= occur on the leaves of
dittany of Crete, mullen, and on the calyx of lavender flowers.
The dittany of Crete (Plate 11, Fig. 3) hair is smooth-walled, and
the branches are alternate.
In mullen (Plate 11, Fig. 1) the hairs have whorled branches, the
walls are smooth, and the cell cavity usually contains air.
[Illustration: PLATE 10
MULTICELLULAR MULTISERIATE NON-BRANCHED HAIRS
1. Cumin (_Cuminum cyminum_, L.).
2. Marigold (_Calendula officinalis_, L.).]
[Illustration: PLATE 11
MULTICELLULAR UNISERIATE BRANCHED HAIRS
1. Mullen leaf (_Verbascum thapsus_, L.).
2. Lavender flowers (_Lavandula vera_, D. C.).
3. Dittany of Crete (_Origanum dictamnus_, L.).]
The lavender hairs (Plate 11, Fig. 2) have mostly opposite branches,
and the walls are rough. Thus the multicellular branched hairs may be
divided into subgroups which have alternate, opposite, whorled, or in
certain hairs irregularly arranged branches. Each class may be again
subdivided according to color, character of cell termination, etc.,
as cited at the beginning of the chapter.
Occasionally multicellular hairs assume the form of a shield (Plate
12, Fig. 1); in such cases the hair is termed peltate, as in the
non-glandular multicellular hair of shepherdia canadensis.
Hairs grow out from the surface of the epidermis in a perpendicular,
a parallel, or in an oblique direction. Hairs which grow parallel or
oblique to the surface are usually curved, and the outer curved part
of the wall is usually thicker than the inner curved wall.
The mature hairs of some plants consist of dead cells. In other
plants the cells forming the hair are living. When dried, those
hairs, which were dead before drying, contain air; while those hairs
which were living before drying, show great variation in color and in
the nature of the cell contents. The contents are either organic or
inorganic. The commonest organic constituent is dried protoplasm. In
cannabis indica are deposits of calcium carbonate.
=Multicellular multiseriate branched hairs= are the ultimate division
of the pappus of erigeron, aromatic goldenrod, arnica, grindelia,
boneset, and life-everlasting.
The hairs of erigeron (Plate 13, Figs. 1 and 2) are slender; the
walls are porous. Each hair terminates in two cells, which are
greatly extended and sharp-pointed; the branches from the basal part
of the hairs (Plate 13, Fig. 1) are of about the same length as the
apical branches.
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