Convolvulus L. Sp. Pl. 1: 153 (1753)
Rhodorhiza Webb in Bot. Reg.. Misc. 69 (1841)
Convolvulus arvensis L.
The genus is essentially temperate in its distribution. The most important centres of diversity are to be found in the Mediterranean (including Macaronesia), East Africa, Central Asia and Arabia. Southern Africa, temperate south America and Australasia also harbour significant numbers of species. There are only three species in north America although Calystegia, that constitutes a monophyletic group nested within Convolvulus, is diverse there. Convolvulus arvensis is a widely distributed weed species.
Carine et al (2004) identified two major groupings within
the genus. The first comprises perennial, mostly erect plants which have
sessile, always entire leaves. Chromosome numbers for this group are 30, 36 and
60. The second clade includes Calystegia and comprises species that have
distinctly petiolate leaves that are sometimes divided. The habit is variable
but typically, trailing or climbing. Chromosome numbers reported for this clade
are 20, 22, 24, and 28 (or multiples thereof). A project is currently underway
to expand the sampling of Carine et al (2004) more widely across the genus to
better understand morphological evolution and the classification of the genus.
Carine, M. A., Francisco-Ortega, J., Santos-Guerra, A. and Russell. S. J. (2004). Relationships of island and continental floras: molecular evidence for multiple colonisations into Macaronesia and subsequent back-colonisation of the continent in Convolvulus L. American Journal of Botany 91: 1070-1085.
Sa’ad, F. 1967. The Convolvulus species of the Canary Islands, the Mediterranean region and the near and Middle East. Medelingen van het Botanisch Museum en Herbarium van de Rijksuniversiteit te Utrecht 281: 1–288.