Leaves offer diagnostic characteristics which serve in
quality control of leaf drugs
Shape, size and wall structure of the epidermal cells
Straight –walled epidermal cells are found in medicinal plants such as coca and Senna leaves
Wavy-walled epidermal cells are in found in Datura stramonium, Hyoscyamus niger and Atropa belladonna.
Form, distribution and relation to epidermal cells of the stomata
Stomata are classified on the basis of subsidiary cells into; ·
Anomocytic Stomata
o When cells surrounding the stomata resemble other epidermal cells ·
Anisocytic stomata
o Stoma is surrounded by three or four subsidiary cells one of which is markedly smaller than others ·
Paracytic stomata
o Two subsidiary cells with their long axes parallel to the pore ·
Diacytic stomata
o Two subsidiary cells with their long axis at right angle to the pore of the stomata
o Variations among anisocytic, paracytic and diacytic types of stomata: ·
Actinocytic type
o Subsidiary cells are arranged along the radii of a circle
Form, distribution and abundance of epidermal trichomes
Trichomes offer physical and chemical protection from microbes, aphids and insects.
Types of trichomes are characteristic of a plant family or genus
Clothing trichomes –cover surface of the leaf
Glandular trichomes –may be unicellular or multicellular (they store ergastic/drug substances) · Multicellular trichomes may be;
o Uniseriate, biseriate, multiseriate or complicated branched structures
