Aristolochiaceae

Birthwort family
California Pipevine (Aristolochia californica)
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Magnoliids
Order:	Piperales
Family:	Aristolochiaceae Juss.
Subfamilies
Aristolochioideae Asaroideae
Synonyms
Asaraceae Vent. Sarumaceae Nakai, nom. nud.

The Aristolochiaceae, or the Birthwort family, are a family of flowering plants with 7 genera and about 400 species belonging to the order Piperales. The type genus is Aristolochia L.

Description

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.

Classification

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Phylogeny Group, place the family Aristolochiaceae in the order Piperales, but it is still quite common, though superseded, for the Aristolochiaceae to be assigned, sometimes with some other families, their own order (Aristolochiales).

Phytochemistry

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.

Ecology

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

Subfamily Aristolochioideae Aristolochia L. – Pipevine Asiphonia Griff. Pararistolochia Hutch. & Dalziel Thottea Rottb.

Subfamily Asaroideae Asarum L. – Wild ginger Hexastylis Raf. – Little brown jug Saruma Oliv.

Excluded genera

• Lactoris Phil. -> Lactoridaceae

External links

• International Agency for Research on Cancer evaluation
• Dietary Supplements: Aristolochic Acid, U.S. Food and Drug Administration alerts
• Health Canada advising not to use products labelled to contain Aristolochia