Aristolochia

Aristolochia
	Calico Flower (Aristolochia elegans); Calico Flower (Aristolochia elegans)
Scientific classification
Kingdom:	Plantae;
Division:	Magnoliophyta;
Class:	Magnoliopsida;
Order:	Piperales;
Family:	Aristolochiaceae;
Genus:	Aristolochia; L.
Species
	See text

Aristolochia, known as birthworts, is a large genus of plants with over 500 species, belonging to the Birthwort family (Aristolochiaceae).

This is a genus of evergreen and deciduous woody vines and herbaceous perennials. They are widespread and occur in the most diverse climates, but not in Australia.

The smooth stem is erect or somewhat twining.

The simple leaves are alternate and cordate, membranous, growing on leaf stalks. There are no stipules.

File:Aristolochia.littoralis2web.jpg

Calico Flower (Aristolochia elegans) - leaves

File:Aristolochia sp.jpg

Ornamental Aristolochia

The flowers grow in the leaf axils. They are inflated and globose at the base, continuing as a long perianth tube, ending in a tongue-shaped, brightly colored lobe. There is no corolla. These flowers have a specialized pollination mechanism. The plants are aromatic and their strong scent attracts insects. The inner part of the perianth tube is covered with hairs, acting as a fly-trap. These hairs then wither to release the fly, covered with pollen. The appearance of the flowers gives rise to the genus' common name Dutchman's pipe.

The calyx is one to three whorled, and three to six toothed. The sepals are united (gamosepalous). There are six to 40 stamens in one whorl. They are united with the style, forming a gynostemium.

The ovary is inferior and is four to six locular.

The fruit is dehiscent capsule with many endospermic seeds.

Some species are commonly called Dutchman's Pipe or Pipevine (Aristolochia macrophylla) because the flowers resemble a meerscahum pipe, Birthwort (Aristolochia clematitis) because the flower shape resembles a birth canal and so because of the Doctrine of signatures was used in childbirth, and Virginia Snakeroot (Aristolochia serpentaria) because the root was used to treat snakebite. Birthwort was given to women in labor to expel the placenta, but since aristolochic acid is a poison, it sometimes resulted in the mother dying.

Some people claim aristolochic acid cures wounds or snakebites, that a decoction of birthwort stimulates the production of white corpuscles and increases their activity, and that birthwort contains a disinfectant which drains off fluid from the wound. Citations to back up these claims have not been provided.

Birthwort was highly-regarded by the ancient Egyptians, Greeks and Romans.

Epidemiological and laboratory studies have shown the toxicity of herbal remedies containing plant species of the genus Aristolochia. Herbal compounds containing Aristolochia are classified as a Group 1 carcinogen by the International Agency for Research on Cancer.

In July 1999, two cases of nephropathy associated with the use of Chinese botanical preparations were reported in the United Kingdom (1). These preparations were shown to contain aristolochic acid. Biopsy samples showed extensive loss of cortical tubules with interstitial fibrosis. Previously, a series of end-stage renal disease cases had been reported from Belgium associated with a weight loss treatment where one ingredient was suspected of being substituted with an aristolochia species. More than 100 patients were identified with nephropathy following the ingestion of this preparation from the same clinic from 1990-1992 Many required renal transplantation or dialysis. Subsequent follow up of these patients has shown they are at an increased risk of urological cancer.

Evidence is building that contamination of grains with Aristolochia clematis is a cause of endemic Balkan nephropathy a cause of renal disease in Croatia and Serbia {[1]]

Many species of Aristolochia are food for larvae of Swallowtail butterflies.

Some reference books state that the Latin name Aristolochia was developed from Greek etymons meaning aristos, "best", and locheia, "childbirth" or "childbed".