Corymbia ficifolia (formerly known as Eucalyptus ficifolia) commonly called the red flowering gum or Albany red flowering gum is one of the commonly planted ornamental trees in the broader eucalyptus family.
Corymbia is a genus of about 113 species of trees that were classified as Eucalyptus species until the mid-1990s. It includes the bloodwoods, ghost gums and spotted gums. DNA research in the 1990s showed that the Corymbia group is more closely related to Angophora than to Eucalyptus, and are probably best regarded as a separate genus. All three genera – Angophora, Corymbia and Eucalyptus – are closely related, often difficult to tell apart by external features and are still commonly referred to as eucalyptus or gum trees.
Corymbias are readily distinguished as gum trees that form corymb inflorescence. A corymb has irregularly lengthened pedicels (lower pedicles are longer and upper pedicels are shorter) that help form a flat-topped inflorescence.
Development of the flower from the bud stage
Corymbia ficifolia flowers very prolifically during summer.
The showy part of the flowers are the red filaments of the stamens. Instead of having petals and sepals, a flower has an hypanthium (base) and an operculum (lid). (The hypanthium and operculum may have similar origins as both petals and sepals combined.) The operculum splits open to release the stamens out. Stamens are male reproductive structures made up of anthers and filaments. The anthers produce pollen grains.
The female reproductive structure is called the pistil. It is made up of the stigma, style and ovary. The stigma receives pollen grains. The male nuclei of the pollen grains transferred through the tissue of the style into the ovary. The ovary comprises of 4 carpels. Each carpel contains numerous ovules. The male nuclei fertilize the female nuclei in the ovule. The ovule develops into a seed. The ovary becomes a fruit (gum nut).
The structure of the flower
The development of the fruit
The ovary develops into a fruit. The fruit bears seeds. Seeds are dark brown to black, ellipsoidal with terminal wing.
Mature fruit is about 40 mm long and 20 mm wide, disc vertically descending, valves 4 (rarely 3), deeply enclosed.
The leaves and the stem
The leaves are long and the length is about four times the width. The upper epidermis is apple-green in colour and the lower epidermis is pale apple-green. The midrib is yellow.
Appearance of the whole plant which provided the plant specimens for study
Botanical drawings
The above botanical drawing by Miss Jacqueline Pemberton, Dip SBA (dist), accurately and very elegantly depicts the development of the flower buds to fruit. It may not be possible to show all the structures in a single photograph. Artists are able to merge a few images into a single botanical drawing. This is the reason that botanical drawing can never be replaced by photography.
A Request
There are gaps in my botanical knowledge of the gum trees. Suggestions and guidance are most welcome. Thank you very much in advance.
email: patrick.i.siu@gmail.com
Acknowledgements:
I would like to thank Miss Miss Jacqueline Pemberton, Dip SBA (dist), most sincerely for allowing me to use her superb botanical drawing and her kind advice on the topic.
Bibliography
https://en.wikipedia.org/wiki/Corymbia
https://www.anbg.gov.au/cpbr/cd-keys/euclid3/euclidsample/html/Corymbia_ficifolia.htm
http://www.botanicalartsocietyaustralia.com/dev/jacqueline-pemberton/
Patrick Siu Chinese Calligraphy & Landscape Painting 蕭燿漢談書畫 
