Dienstag, 25. September 2012

Plant of the Day (September 25th, 2012) - Aristolochia clematitis L.

Today's “Plant of the Day” is Aristolochia clematitis L. from the Aristolochiaceae family. The common German name of this species is “Gewöhnliche Osterluzei”. In English, it's called “European Birthwort”.

A. clematitis - habitus

It's a herbaceous perennial plant, which can reach heights between 30 and 100 centimetres (12.0 to 39.3 inches). The stalk is unbranched and grows upright from a creeping rhziome. The large leaves are heart-shaped and have a long petiole. They are bald and have a lobed margin. Their colour is a yellowish green.

A. clematitis -  leaf

The flowers are arranged in whorls in the axillary of the upper leaves, what is a very conspicuous kind of inflorescence. They are funnel-shaped, short stalked and their petals have a sulfur-yellow colour. The flowers of A. clematitis are designed to work as a trap for insects like flies. A fly flies into the flower, stick to the hairs and is caught within the flower. After pollination, the hairs wither and the flower dismisses the insect by tilting.
Flowering time is between May and June and the ripe fruit is a black, pear-shaped capsule.

A. clematitis - flowers

A. clematitis is native to the Mediterranean but was brought to the Rest of Europe during the Middle Age. It prefers warm places and nutrient-rich soils. So, A. clematitis is a typical species of vineyards but can also be found on warm river banks or riparian forests (I found this individual at the shores of the River Rhine during my Field Trip in June 2012). During the Middle Age, the species was widespread, but today it is rare. However, some plants were planted in gardens and grew wild later..

A. clematitis - leaf

A. clematitis is also one of the oldest medicinal plant of the World. Its ingredients, the Aristolochic acids, were used already in the antique and by the American Indians to cure snakebites. However, the most common use of this plant was to accelerate and ease the birth, because Aristolochic acids have a travail promoting effect. This is also the reason for the English name “Birthwort” and also for the Latin name (“Aristos” = “the best”; “lockeius” = “to do with birth”).

A. clematitis - flowers

Because of the travail promoting effect, A. clematitis was also used as abortifacient but this could be very dangerous, because Artiolochic acids are also very toxic. They can cause kidney failure, promote the formation of ulcers and even damage the genetic material. Therefore, the plant is no longer used as a medicinal plant in many countries. and the use of Aristolochic acids is forbidden.

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