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Monday, March 15, 2010

Jade Vine Strongylodon macrobotrys

I first encountered this sensational plant at the Chelsea Flower Show in 1973, when I was a student, and didn't see it again until I visited its native country - the Philippines - in the late 1980s. I don't think I've seen another plant with a flower colour that can match it. It's now an endangered species, disappearing along with its tropical rainforest habitat. The plant is a climber and the flowers are pollinated by bats. The large racemes of flowers are pollinated by bats and dangle from long racemes from below the tree canopy - a habit known botanically as flagelliflory, that provides an uninterrupted flight path for bat pollinators.
 Fortunately we now have a plant flourishing in the Botanic Garden tropical house at Durham University. This is the first raceme of flowers to come into bloom this year and there are about another twenty or so still in bud, so it will be putting on a fine display over the coming weeks. 

Jade vine's flowers are typical of the pea family, with a standard petal and two wing petals on either side of a keel petal that's shaped like a claw. Inside the keel lie the stamens and the stigma at the tip of a long style. When a bat probes for nectar in the throat of the flower it pushes downwards on the keel petal and the stigma protrudes, forcing out a plug of pollen onto the bat's fur. It's a pity we don't have any suitable resident bats in our glashouse.

There's also a fine specimen growing in the glasshouses at Roundhay Park near Leeds and another at Cambridge University Botanic Garden.