The genus Cinnamomum

Botany and Crop Improvement of Cinnamon and Cassia 23
22.7 cm with a mean of 13 cm; leaf breadth 3.3–8.3 cm with a mean of 5.1 cm. Leaf
size index varies from 0.29 to 1.7, the mean being 0.7 (Krishnamoorthy et al., 1992).
C. cassia has larger lanceolate leaves having a mean length of 16.25 cm and a breadth
of 3.8 cm; the L/B value being 4.26 versus 2.28 in the case of C. verum and 2.05 for
C. verum from Sri Lanka. The leaf morphological characteristics of cinnamon and some
of the related species are given in Table 2.1.
C. camphora is not closely related to cinnamon, as it belongs to the sub genus
camphora, characterised by buds covered with orbicular, concave, silky, caducous, and
imbricating scales, while the species belonging to the subgenus malabatrum have
naked buds or buds with very small scales. Santos (1930), Shylaja (1984) and
Ravindran et al. (1993) studied the leaf morphological and anatomical characteristics
of cinnamon and cassia. Baruah et al. (2000) reported the leaf characteristics of Indian
cassia.
Leaf anatomy
In most of the economically valuable species the leaves are triplinerved, except in
camphor tree (and other species that belong to the section camphora) where the leaves
are penninerved. Santos (1930), Shylaja (1984) and Bakker et al. (1992) reported leaf
anatomy of Cinnamomum spp. The leaf structure is similar to that of a typical dicot leaf.
Both the upper and lower epidermes are covered by more or less thick cuticles.
Variations, however, are noted among species. Bakker et al. (1992) noted cuticle thickness
variation from 2 to 17 m in different species, and they identified four classes
based on cuticle thickness. C. verum belongs to the first group (3 m), C. cassia to the
second group (3–8 m).
Palisade consists of a single layer of elongated cells having large chloroplasts. The
relative thickness of palisade and spongy parenchyma varies in different species and
even within a species. In C. verum (India) palisade is thicker than spongy parenchyma,
Table 2.1 Leaf morphological characters of some Cinnamomum spp.
Species LL LB L/B LT ET PT SPT PL
(mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm)
C. verum (Indian) 81.2 35.5 2.28 0.231 0.015 0.101 0.050 12.7
C. verum (Sri Lanka) 99.0 48.2 2.05 0.197 0.013 0.067 0.096 10.9
C. verum (wild) 81.2 33.0 2.46 0.218 0.013 0.075 0.111 10.0
C. cassia 162.5 38.1 4.26 0.171 0.023 0.054 0.062 15.2
C. camphora 66.0 23.6 2.79 0.197 0.026 0.073 0.070 14.4
C. malabatrum*
1. 172.7 40.6 4.25 0.218 0.013 0.075 0.104 13.9
2. 119.3 45.7 2.61 0.200 0.013 0.059 0.109 15.2
3. 195.5 66.0 2.96 0.236 0.013 0.106 0.098 11.4
4. 83.8 33.0 2.53 0.244 0.013 0.085 0.122 10.1
Source: Shylaja, 1984.
Notes
* This is the most variable species related to C. verum.
LL – leaf length; LB – leaf breadth; L/B – leaf length/leaf breadth; LT – leaf thickness; ET – epidermal thickness;
PT – palisade thickness; SPT – spongy parenchyma thickness; PL – petiole length.