The genus Cinnamomum

(a)
(b)
Morning
Botany and Crop Improvement of Cinnamon and Cassia 45
CI
CI
Afternoon Night Morning Afternoon
Figure 2.12 Flower biology of cinnamon. (a) Flowers of cinnamon at different stages. (b) Flowering
behaviour in cinnamon (synchronised dichogamy).
receptive. The stamens of the third whorl now occur separated from those of the first
and they now adhere to the pistil. The anthers dehisce 30–60 minutes after the flower
opening. After about five hours the flower again closes and will not open again.
Variations were noticed in the time of occurrence and duration of the first and second
stages. Joseph (1981) noted that out of 55 plants studied, in 33 the first stage occurred
in the morning, with the second stage occurring at about noon next day. In 22 plants
the first stage occurred at about noon with the second stage occurring the next morning.
On any day both stage one and two flowers occurred randomly in a population of
trees, and functionally female and functionally male flowers (female and male phases)
would appear both in the morning and at noon. Thus the flower of cinnamon is highly
adapted for cross-pollination.
A similar situation is present in another Lauraceae plant avocado, Persea americana
(Sedgley and Griffin, 1989). Here all flowers show protogynous dichogamy, the female
and male stages are separated by a distinct time period, during which the flower closes
completely. During the female phase the pistil is conspicuous and receptive, anthers
reflexed against the petals and not dehisced. In the male phase the pistil is obscured by
the anthers, which are now dehisced. Two flowering types occur: (a) female phase in the
morning and male phase next day after noon; and (b) female phase in the afternoon and