Abstract
Populations of Atriplex canescens var. gigantea were found in Lamta, Bouficha-Enfidha (central Tunisia), and Medenine (southern Tunisia). Literature data concerning the presence of this species in Tunisia are contradictory but now our data confirm its occurrence in the country. On the other hand, this variety is reported in the present paper for the first time both in Tunisia and in North Africa in general. Morphological characters and ecological data are presented, as well as notes about patterns of infraspecific variability of A. canescens. Nomenclatural notes on infraspecific names in A. canescens, as well as on the closely related species A. garrettii, are provided. The types of the names A. canescens var. laciniata, A. canescens var. macilenta, A. garrettii, Obione occidentalis var. angustifolia, and Pterochiton occidentale, that in earlier publications were erroneously considered to be holotypes, are in fact lectotypes (for most of taxa) under Art. 9.10 of the ICN. Isolectotypes were found at CAS (A. canescens var. laciniata and A. canescens var. macilenta), GH (A. canescens var. macilenta), and YU (Atriplex nuttallii).