Cortex. The cortical parenchyma cells consist of tangentially elongated cells which are oval in outline.
Phloem. The phloem consists of sieve cells, phloem parenchyma, and of bast fibres.
PLATE 95
Cross-Section of Stem of Spigelia marylandica, L.
1. Papillate epidermis. 4. Phloem. 7. Inner phloem.
2. Cortical parenchyma. 5. Cambium. 8. Pith.
3. Bast stereome. 6. Xylem.
The sieve cells are small, and with thin, white, angled walls.
The phloem parenchyma resembles the sieve cells, but they are larger.
The bast fibres are rounded in outline and the walls are thick, white, non-porous, and non-striated.
Cambium. The cambium cells are rectangular in shape or the walls are collapsed and the cells indistinct.
Xylem. The xylem contains vessels, wood parenchyma, medullary rays. The vessels are small and angled, the walls are thick and white.