Chorological and taxonomic notes on African plants, 2

Abstract

The taxonomy of complicated native African taxa, Biscutella maritima (Brassicaceae) and annual species of Sesuvium (Aizoaceae) is discussed. The distribution of B. maritima is widened to the most of the coastal areas of NE Algeria and N Tunisia. Morphological differences with regard to other North African members of Biscutella ser. Biscutella are reported to facilitate the identification of B. maritima. We propose to accept four annual Sesuvium species (instead of the one previously accepted species, S. sesuvioides sensu amplissimo) with different distributions in Africa: S. digynum, S. hydaspicum, S. sesuvioides s.str. and S. nyasicum. A delimitation key based on morphological and carpological characters is provided. Lectotypes of S. digynum, S. digynum var. angustifolium, S. hydaspicum, S. nyasicum, Diplochonium sesuvioides (Sesuvium sesuvioides) and Trianthema polysperma (synonym of Sesuvium hydaspicum) are selected. Other discussed taxa belong to the alien elements of the flora. Atriplex semibaccata (Amaranthaceae-Chenopodiaceae) is reported as a new species for Cape Verde. Gaillardia × grandiflora (Asteraceae) is discovered as a new species for Africa found in Morocco. Prosopis velutina (Fabaceae) is collected for the first time in Northern Africa (Morocco). Mollugo verticillata (Molluginaceae) is recorded as a new species for DR Congo. Its morphology, including seed ornamentation, is discussed in reference to other similar-looking Molluginaceae. Incidence of American species Heterotheca subaxillaris (Asteraceae) in North Africa is discussed. Vernonanthura polyanthes (Asteraceae) is recorded as a naturalized invasive species in eastern Zimbabwe. It seems to be the first documented discovery of this ergasiophyte in Africa.