Aristolochiaceae

taxobox
name = Birthwort family


image_caption = Calico Flower ("Aristolochia littoralis"), about to open
regnum = Plantae
unranked_divisio = Angiosperms
unranked_classis = Magnoliids
ordo = Piperales
familia = Aristolochiaceae
familia_authority = Juss.
subdivision_ranks = Genera
subdivision = See text.|

The Aristolochiaceae, or the Birthwort family, are a family of flowering plants with 8 genera and about 400 species belonging to the order Piperales. The type genus is "Aristolochia" L.

The Aristolochiaceae are magnoliids, a basal group of angiosperms which are not part of the large categories of monocots or eudicots.

Some newer classification schemes, such as the Update of the Angiosperm Phylogeny Group, place the family Aristolochiaceae in the order Piperales, but it is still quite common, though superseded, for the Aristolochiaceae to be assigned, sometimes with some other families, their own order (Aristolochiales).

They are mostly perennial, herbaceous plants, shrubs, woody vines or even lianas.

The membranous, cordate simple leaves are spread out, growing alternately along the stem on leaf stalks. The margins are commonly entire. There are no stipules.

The bizarre flowers are large to medium-sized, growing in the leaf axils. They are bilaterally or radially symmetrical.

Many members of "Aristolochia" and some of "Asarum" contain the toxin aristolochic acid, which discourages herbivores and is known to be carcinogenic in rats. "Aristolochia" itself is carcinogenic to humans.

Pipevine swallowtail butterflies lay their eggs on pipevine ("Aristolochia" species), and the larvae dine on the plant but are not affected by the toxin, which then offers the adult butterfly protection against predators.

Genera

*"Apama"
*"Aristolochia" : Pipevine
*"Asarum" : Wild ginger
*"Euglypha"
*"Holostylis"
*"Saruma"
*"Thottea"
*"Hexastylis" : Little brown jug

External links

* [http://monographs.iarc.fr/htdocs/monographs/vol82/82-01.html International Agency for Research on Cancer evaluation]
* [http://www.cfsan.fda.gov/~dms/ds-bot.html U.S. Food and Drug Administration alerts]
* [http://www.hc-sc.gc.ca/ahc-asc/media/advisories-avis/2001/2001_91_e.html Health Canada advising not to use products labelled to contain Aristolochia]