6. Pollination and natural hybridization

Over the past decade, much has been learnt about the interrelationships between the Cape orchids and their pollinators. This section includes an intriguing account of the ways in which orchid flowers are specifically adapted for pollination by various insects and even birds. Strikingly detailed photography portrays examples of various pollination strategies such as mimicry and sexual deception by orchid flowers. The highly specialised pollination of orchids highlights the remarkable interconnection between living organisms and the intricate mechanisms that promote their survival in nature. The partnership between orchid flowers and their pollinators is one of the most compelling and fascinating aspects of natural history. Orchids, like all other plants, are literally rooted to one spot and this means that they face the challenge of how to acquire pollen—the botanical equivalent of sperm—from one flower to another, in order that they can achieve the fertilization that is needed to produce seeds. Most do so by using animals as couriers of their pollen. Flowers are simply the reproductive organs of the plant cloaked in colourful and often fragrant layers of petals and sepals. It is these allurements that entice animals to visit the flowers and deposit and receive pollen.

Many discoveries have been made in the past ten years and the list of Cape orchids with known pollinators has increased from about five in the early 1990’s, to about 50 species at present—still a small fraction of the total number of orchid species in this region. Clearly, much remains to be revealed . . .

Clusters of Bonatea speciosa pollinaria are transported from flower to flower, attached to the eyes of hawkmoths (Theretra capensis). Goukamma Nature Reserve, southern Cape Floristic Region (29 October 2005).

	With its passion for red, Aeropetes tulbaghia, the Mountain Pride butterfly, alights upon and pollinates Disa uniflora. Pollinia dangling from its legs deposit pollen massulae onto the large fleshy stigma. Table Mountain, Cape Peninsula (February 1997).
	A letter and drawing from Celestine du Plessis to Dr Harry Bolus (February 20, 1911), describes a long-proboscid horsefly (Philoliche gulosa) with an adherent pollinium of Disa harveiana subsp. longicalcarata, found near Porterville, western Cape Floristic Region.