The genus Cinnamomum

52 P.N. Ravindran et al.
centre. The cell wall formation begins from the micropylar end and, at the globular
stage of the embryo, the entire endosperm becomes cellular.
Fruit and seed
The fruit is an oblong or cylindrical berry. Testa 10–12 cells thick; outer epidermis is
composed of short radially elongated cells; mesophyll unspecialised, composed of
longitudinally elongated cells with unlignified spiral thickening on the radial walls.
Vascular bundle of the raphe divides into two post chalazal branches ascending to the
micropyle. Pericarp consists of five layers: (i) outer epidermis that is short celled;
(ii) outer hypodermis, four to five cells thick as stone cells; (iii) pulpy mesophyll four
to five cells thick, thin walled; (iv) fibrous endomesophyll (inner hypodermis), fourcells
thick, the fibres tangentially elongate; and (v) inner epidermis composed of columnar
cells in one layer (Choudhury and Mitra, 1953; Sastri, 1958). Fruit disposal is
conducted mostly by birds (Sedgley and Griffin, 1989) (Fig. 2.17).
Mature seed is exalbuminous. The adult embryo fills the entire seed and has two
massive cotyledons, enclosing the radicle and plumule, the latter shows leaf primordia.
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Figure 2.17 Seed structure of cinnamon. 1. L.S. of mature fruit. 1. Fruit wall; 2. Seed coat;
3. Cotyledons; 4. Plumule. 2. L.S. of mature fruit wall and seed coat. 1. Outer epidermis;
2. Stone cells; 3. Parenchymatous cells; 4. Fibrous cells; 5. Columnar stone cells; 6. Seed
coat. 3. L.S. of mature seed coat. 1. Outer epidermis; 2. Parenchymatous cells; 3. Inner
epiderminal cells with helical thickening. 4. L.S. of apical portion of young seed
of C. iners. 1. Stone cells; 2. Outer integument; 3. Cells with helical thickening;
4. Nucellus; 5. Endosperm; 6. Inner integument; 7. Embryo.
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