Histology of medicinal plants

by William James Mansfield

The walls of hairs are composed of cutin, of lignin, and of cellulose.

PERIDERM

The periderm is the outer protective covering of the stems and roots of mature shrubs and trees. The periderm replaces the epidermis. The periderm may be composed of cork cells, stone cell-cork, or a mixture of cork, parenchyma, fibres, stone cells, etc.

CORK PERIDERM

The typical periderm is made up of cork cells. Cork cells vary in appearance, according to the part of the cell viewed.

PLATE 14
Multicellular Multiseriate Branched Hairs

1. Apical hairs arnica (Arnica montana, L.).
2. Basal hairs arnica (Arnica montana, L.).
3. Apical hairs grindelia (Grindelia squarrosa, [Pursh] Dunal).
4. Basal hairs grindelia (Grindelia squarrosa, [Pursh] Dunal).

PLATE 15
Multicellular Multiseriate Branched Hairs