A cartoon bumblebee?
It looks like a cartoon bumblebee – how else can I describe the flower of Aerides odorata (Orchidaceae)? It is thick and fleshy, the petals and sepals (spare the fleshy lip) all resemble wings and they are elegantly held in one plane. The spur really accentuates the shape of a wasp, being prominent and pointing forward. The flowers are white and pink, like small scoops of strawberry ice cream.
The whole swarm is here buzzing in a Dipterocarpus alatus tree at Dokmai Garden in Chiang Mai, northern Thailand.
The side lobes of the lip are really tall, making the lip look swollen. The beak-like column reveals it is an orchid of the Aerides genus. It is in fact the type species on which the scientific genus description was made. The ‘eyes’ are the male pollinia hidden by a hymen which will open when the pollinating insect touches the ‘beak’.
It is native from the Himalayas to most of Southeast Asia and prefers a sunny position up in a tree, which is why a deciduous tree is a good choice in a Chiang Mai garden. The epithet ‘odorata’ implies a fragrance, but I have never felt any fragrance from any wild Thai variety, not even at night. I could be blocked to its fragrance, but I do catch the fragrance of other Aerides. With such a huge geographical range there is plenty of room for local adaptations and varieties. Perhaps ‘Aerides odorata‘ is in fact a cluster of several closely related species, each with its different morphology, colour scheme and chemistry as an adaptation to different pollination biology? Only molecular analyses of their DNA can reveal if there is a gene flow (mating) between the many different populations or not. From the orchid conservation aspect it is important to work with local varieties, since a Himalayan variety might have problems surviving in a Borneo rain forest. The cloned strains grown for orchid houses abroad may degenerate quickly (i.e. develop new shapes, forms and fragrances selected by gardeners, not by nature) and so they provide little information of importance to science.
If any of our readers have experience from Thai wild strains and their fragrance, or have seen the presumably large insect needed to open the stiff flowers, please let me know.
Text & photo: Eric Danell