Figure 2.5 Foliar epidermal characteristics of some Cinnamomum spp. 1. C. tamala; 2. C. verum; 3. C. cassia; 4. C. camphora; 5. C. panthenxylon. a-lower epidermis; b-upper epidermis. In 1, 2 and 3 the cell walls are sinuous and stomata anomocytic; in 4 and 5 the cells are straight and stomata paracytic.
Botany and crop improvement of cinnamon and cassia
by Ravindran P. N., Shylaja M., Babu K. N., Khrishnamoorthy B. (2004)
pp.30-32 in “Cinnamon and Cassia – The genus Cinnamomum” – Editors Ravindran P. N., Babu K. N., Shylaja M. – CRC Press –
Cinnamon leaves are hypostomatic, with stomata confined to the lower surface of leaves. Stomata are anomocytic, surrounded by a variable number of cells that are indistinguishable in size or form from the rest of the epidermal cells (Fig. 2.5).
In C. camphora, stomata are of paracytic type, i.e. they are accompanied on either side by one or more subsidiary cells parallel to the long axis of the pore and guard cells. The guard cells may be equal or unequal in size and are attached to each other at the margins of the concave side with the aperture lying in between the walls.
Rare occurrence of other types of stomata was also reported (Baruah and Nath, 1997) (Fig. 2.6). Guard cells are unevenly thickened, and thickening is heavy along the aperture. Stomatal characters are given in Table 2.4.
Stomatal frequency is found to be lower in C. camphora and in C. cassia while C. verum and C. malabatrum have a higher frequency. Guard cell dimensions do not show much variation among species except in C. camphora, in which the dimensions are higher than those in other species.