Friday, January 15, 2010

Cressida Butterfly Vine

Aristolochia meridionalis (Aristolochia sp D’Aguilar Range)
I was delighted to find this tiny plant at a friend’s place in Blackbutt, yesterday. We almost missed it, thinking it was a bellvine Ipomoea plebeia, but a sharp-eyed member of the company pointed out its tiny flower - definitely an Aristolochia!
There were several of the plants there, and we dug this one up, finding that it had a substantial fleshy root. That’s the secret of its this little vine’s ability to survive droughts, fires, and perhaps gardeners who attempt to weed it out, mistaking it for bellvine.
It is normally regarded as deciduous, which in the case of small vines like this one can mean not just loss of leaves every winter, but the loss of everything above ground. That it should have flowered while the plant seems so small probably means that it is really quite an old plant.
Like its cousin the Richmond birdwing butterfly vine, this is an important butterfly host plant, needed by the beautiful clearwing butterfly (Cressida cressida). Each little cressida vine can only host two or three caterpillars, so lots of them are needed to support a good population of clearwings.
I took the plant to an SGAP meeting last night, and a member commented on the resemblance of the flower to those of some of the carnivorous plants - and he is actually right that this flower is a trap.
The flowers catch a little midge, which they need as a pollinator - but aren’t seriously sinister. They have two stages - a female stage, when they are able to be pollinated, followed by a male stage, when their pollen ripens. In the first stage they are open for visitors, and exude a smell resembling a female midge pheromone. The gullible little males crawl deep into the flower’s long tube, in the hope of finding a mate. The flower traps them there, and keeps them until its pollen is ripe, only then releasing them with their new pollen load.
They’re not smart, these little midges. They go on to visit the next interesting-smelling flower, and get themselves trapped all over again.
The midges live in damp leaf litter and are said also to like being amongst the leaves of matrushes, Lomandra species - so successful reproduction of pipe vines depends on having the right environment for midges, as well as for their own growth.

Pipevines and the
Doctrine of Signatures

This is an ancient doctrine, but it still influences some modern herbalists. It holds that the appearance of certain plants is a divinely bestowed sign, put there to tell us that the plant is suitable medicine for the human body part it resembles. Kidney-shaped leaves mean kidney medicine, and so on.
The flowers of various species of Aristolochia and Pararistolochia are variously said to resemble a foetus in delivery position, an afterbirth - or a snake. Traditional medicine regarded them as valuable for easing childbirth, inducing abortions, reducing menstrual pain, and curing snakebite. These uses were surprisingly widespread, being practised wherever the different species grew - Europe, Asia, North and South America, and Australia.
Few people nowadays would regard a plant’s “signature” as a reliable guide to its medicinal reliability, yet one suspects that the Aristolochias' use in such widely separated cultures could indicate that they were actually effective to some degree.
However, like many medicinal plants, they should not be experimented with at home, as they are very poisonous. Unwanted effects include destruction of the kidneys, and death. (Another traditional use for one Aristolochia species is as an arrow poison.)

But I think you can see why I got so much pleasure, yesterday, from the discovery of this tiny plant!

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