The genus Cinnamomum

Botany and Crop Improvement of Cinnamon and Cassia 55
Infraspecific variability in C. malabatrum is evident from the divergence of some of the
C. malabatrum collections from the rest.
Bakker et al. (1992) carried out a phenetic analysis of a large number of Cinnamomum
spp. using leaf anatomical characteristics. They applied cluster analysis and the
phenogram constructed based on Manhatten distances indicated ten clusters. According
to this indication C. burmannii and C. verum are in cluster 1, together with many other
species. Within this cluster C. burmannii occupies an independent sub-cluster position,
while C. verum is in another sub-cluster together with 21 other species (including
C. tamala (Indian cassia), C. culitlawan, C. keralaense, C. sintok, etc.). C. cassia is in cluster
2. Different accessions of C. camphora are included in clusters 4, 9 and 10, thereby
indicating the infraspecific variability present in this taxon. In clusters 1 and 2 the
idioblast distribution shows the largest variation. Cluster 3 always possesses mucilage
cells in both mesophyll layers and oil cells in spongy parenchyma. The species in cluster
4 can be recognised by the combination of the following features: presence of both
idioblastic types in both layers; non-sclerified epidermal cells; and, a weakly or nonsclerified
spongy parenchyma. Cluster 5 does not possess a discriminating leaf anatomical
characteristic distribution. Cluster 6 lacks mucilage cells in the spongy parenchyma
and also possesses non-sclerified epidermal cells and spongy parenchyma, a two-layered
sclerified palisade parenchyma and penninerved leaves. Cluster 7 is characterised by the
presence of oil and mucilage cells in both palisade and spongy layers, a thick lamina
and cuticle, a two-layered sclerified palisade parenchyma and triplinerved leaves.
Cluster 8 lacks oil cells and clusters 9 and 10 are characterised by the absence of
mucilage cells. In these last three clusters the idioblast distribution pattern is the
discriminating factor.
Meissner (1864) has subdivided Cinnamomum into two sections, Malabathrum and
Camphora, which was adopted by later florists like Hooker (1886). Further infrageneric
studies have not been made so far (Kostermans, 1986). Bakker et al. (1992) tried to
correlate leaf anatomical characteristics of the species with the existing classification.
They found that most of the species under the section Malabathrum were in groups 1–3.
All these species possess sclerified epidermal cells and/or palisade cells. Those species in
the section Camphora, which fall in groups 4, 9 and 10, lack sclerified epidermal and
palisade cells. Most neotropical species included in the study by Bakker et al. (1992)
were transferred from other genera (such as Phoebe). These species occupy clusters
6 and 9. Nine of these species have penninerved leaves, and they all possess nonsclerified
epidermal cells.
Chemotaxonomy
Shylaja (1984) and Ravindran et al. (1992) carried out chemotaxonomical studies on
C. verum and some of its related taxa occurring in the Western Ghats of Kerala, India.
They have analysed flavonoids, terpenoids and steroids and found much variation
among species. C. verum, C. camphora, C. cassia and C. riparium are chemically very
distinct among themselves and from other species. Much infraspecific chemical
variability was noticed in C. malabatrum. They also found that Sri Lankan and Indian
accessions of C. verum were chemically identical. The above workers also carried out
a centroid clustering analysis of the flavonoid-triterpenoid data, which resulted in
independent clustering of C. verum, C. riparium, C. cassia and C. camphora. Close
clustering resulted between C. perrottettii and C. macrocarpum as well as between