The Convolvulus species of the Canary Isles, the Mediterranean region and the Near and Middle East

This study was undertaken in 1963 at the suggestion of Prof. Dr. J. Lanjouw. As the genus Convolvulus is so large that a revision of all its species would have taken too much time, and as a revision of the African ones alone would not have been interesting because these species do not form a natural group, it was decided to choose a middle way, and to take into consideration also the species occurring in the adjoining countries. This was all the more Indicated as the Convolvulus species of the area which includes besides the Mediterranean region also the area extending eastwards of the latter to the western border of Afghanistan, i. e. such countries as Iraq and Iran, show many signs of affinity. During our study of the species occurring in these parts, it was realized that it would be desirable to consider also those occurring in Afghanistan and Turkmeniskaya and further to the west in the Caucasus, Armenia and a part of the area surrounding the Black Sea. The Canary and Madeira Isles were also included, as they are close to the North African part of this region and as these islands moreover are interesting because they show a high degree of endemism and because some of the Convolvulus species occurring here were regarded by some authors as sufficiently distinct from those found elsewhere to be referred to a genus of their own, a genus for which the name Rhodorrhiza was proposed. The genus Convolvulus was introduced by Linnaeus (1753). In 1789 it was revised by Desrousseaux, who described 107 species under the heading “Liseron”; he divided the genus into two subdivisions, viz. 1° “peduncles with solitary flowers” and 2° “peduncles with numerous flowers”; in the delimitation of the genus he followed Linnaeus.