Starfish Flower, Stapelia variegata, Apocynaceae

Stapelia variegata belongs to a select group of  plants with sapromyophilous flowers - flowers that mimic the scent (and sometimes colour and texture) of carrion, attracting fly pollinators that are deceived into laying eggs on them and accidentally pollinate the flowers as they do so. The odour of flowers with this pollination syndrome can vary - from mildly unpleasant (as in the case of S.variegata, where you need to be quite close to detect it) to truly nauseating (as in the case of Dracunculus vulgaris).

The surface of starfish flower feels like wrinkled flesh and those brown spots are rather similar to the early symptoms of putrification in a pale-fleshed corpse.The inner parts of the flower - known as the corona - are surrounded by a raised ring called the annulus and consist of five horizontal bifurcating segments and five bifurcating, upright horn-like structures, which together appear to guide wandering flies towards the functional reproductive organs, although it's not clear exactly how they do this. The male anthers on the inner corona lobes are in the form of a pollinium so are carried off in their entirety on the leg or proboscis of a visiting fly. The stigma is located within the outer corona lobes, which guide the pollinium attached to a visiting fly onto the stigma surface. You can read a plant breeder's account of Stapelia flower structure and pollination here.


Stapelia is a predominantly South Africa genus of succulent plants which used to be classified within the family Asclepiadaceae (milkweeds). This species is very easy to cultivate as long as it's planted in a well drained compost and not overwatered. This is also an easy species to raise from seed - which is worthwhile because the mottling on the flowers is quite variable - so amongst a batch of seedlings you might find something unusual and interesting.

Wax plant, Hoya carnosa, Asclepiadaceae

The flowers of Hoya carnosa, with their massive drops of glistening nectar, remind me of Man Ray's famous photographs of fake glass tears on a woman's face. They seem as surreal as his photographs - but are genuine enough; whenever I've grown this plant I've had to spend a lot of time cleaning off the black mould that tends to grow on leaves splashed with the sugary secretion. Apparently Victorians like to wear Hoya inflorescences in their coat buttonholes - presumably removing those sticky drops first.

Those petals are pretty extraordinary too - they look as though they're made of fake pink fur.

I've seen bees visiting H.carnosa in my conservatory but it's hard to find information on its natural pollinators in the wild. It seems likely that they are nocturnal moths because there are two published studies which show that there is a circadian rhythm of scent emission (1) and nectar secretion peaking at around midnight (2). Members of the Asclepiadaceae have an unusual pollination mechanism, where insects carry away the whole anthers, as a structure known as the pollinium, that attaches to them via an organ called a translator - similar to the pollination mechanism found in orchids. You can see sketches of Hoya pollinia here. 

Those massive nectar droplets must be the moth's reward for its exertions.

Hoya carnosa seems to have a wide distribution in South East Asia but old gardening books I've consulted indicate that it was introduced to Britain from Queensland in 1802. It's named after Thomas Hoy, who was the Duke of Northumberland's gardener at Syon House at that time. 

The plant seems to flower most prolifically if it's confined to  pots that are not too large and is kept fairly dry in winter. 

Bibliographic references: [1] Planta 174, 242-247 (1988); [2] Botanica Helvetica 116, 1-7 (2006)