Histology of medicinal plants

by William James Mansfield

PLATE 57
Cross-Section of Elder Bark (Sambucus canadensis, L.). 1. Periderm. 2. Lenticel. 3. Phellogen.

PLATE 58
Intercellular Air Spaces

A. Cross-section of uva-ursi leaf (Arctostaphylos uva-ursi, [L.] Spreng.).
1. Irregular intercellular air spaces.
B. Cross-section of the cortical parenchyma of sarsaparilla root (Smilax officinalis, Kunth). 1, Triangular intercellular spaces; 2, Quadrangular intercellular air spaces; 3, Pentagular intercellular air spaces.

PLATE 59
Irregular Intercellular Air Spaces

1. Skunk-cabbage (Symplocarpus fœtidus, [L.] Nutt.)
2. Calamus rhizome (Acorus calamus, L.).

In the rhizome of calamus and other aquatic plants the intercellular spaces are very large. The cells of these plants are arranged in the form of branching chains of cells which thus provide for large intercellular spaces.

The cells of the middle layer of flower petals, like the mesophyll of leaves, is loosely arranged owing to the peculiar branching form of the cells.

Seeds and fruits contain, as a rule, few or no intercellular spaces.