Aristolochia rotunda


Aristolochia rotunda, commonly known as smearwort or round-leaved birthwort, is a herbaceous perennial tuberous plant native to Southern Europe.

Etymology

The genus name Aristolochia derives from the Greek words αριστος meaning "the best" and 'lochéia' meaning 'childbirth', for the old use in promoting uterine contractions. The Latin name of the species rotunda refers to the rounded shape of the leaves.

Description

It grows to long, with slender, glabrescent, unbranched or branched stems. The root, a tuber, reaches in length and sometimes seems out of proportion to the slenderness of the plant. The stem has alternate, large, smooth-edged, heart-shaped, stalkless leaves long that clasp the stem with enlarged, basal lobes. The solitary flowers are tubular, about long, yellowish-green with a prominent, dark brown to dark purple flap, arising from the axils of the leaves; they have an unpleasant smell. The flowering period extends from April to June.

Reproduction

The flowers of Aristolochia rotunda are hermaphrodite, and are pollinated by midges and other small insects, attracted by the smell. The small hairs inside the cup prevent the flies from coming out and flying away. After the pollination these hairs sag and allow them to escape.
This species is a host plant of the caterpillars of an uncommon butterfly, the southern festoon Zerynthia polyxena. In eating the leaves of the plant, the larvae this insect ingest aristolochic acid that make them poisonous to birds.

Distribution

This plant is common in Mediterranean countries from Spain east to European Turkey. It is naturalised very locally in southern England.

Subspecies

Three subspecies are accepted:Aristolochia rotunda subsp. rotunda Aristolochia rotunda subsp. insularis GamisansAristolochia rotunda subsp. reichsteinii E.Nardi

Habitat

This plant occurs along the banks of canals, edges of ditches and fields, sides of roads, meadows, slopes and forests. It prefers chalky soils and moist, shady areas, and grows at altitudes of above sea level.

Chemical constituents

A. rotunda contains aristolochic acids which are carcinogenic, mutagenic, and nephrotoxic.

Additional references

  • Pignatti S. - Flora d'Italia - Edagricole – 1982, Vol. I, pag 135
  • Tutin, T.G. et al. - Flora Europaea, second edition - 1993
  • Björn Rulika, Stefan Wankeb, Matthias Nussa and Christoph Neinhuisb