Phylogeny and reclassification of Lampranthus (Ruschieae, Aizoaceae) in southern Africa

Abstract

Lampranthus consists of 85 species of succulent perennials which are all endemic to southern Africa. Most of its species are restricted to fynbos and regenerate in large numbers after fires. We use nine chloroplast markers to generate a phylogeny with a dense sampling of Lampranthus and some taxa which may be closely related to it. While we found that most of the species belong to one strongly supported “core” clade, we also found three minor clades of Lampranthus that fall outside this core. For Lampranthus we set up a new classification of three subgenera. The clades forming L. subg. Adunci (3 spp.) and subg. Calcarati (1 sp.) are unresolved within the Ruschieae and we treat them as subgenera until their relationships are clarified. Three sections are proposed for L. subg. Lampranthus and we also suggest new synonymy for several species in L. sect. Lampranthus (65 spp.) and sect. Blandi (15 spp.). Roosia and the type species for Esterhuysenia are nested in L. sect. Blandi and so these genera are subsumed under Lampranthus. Esterhuysenia stokoei forms part of Lampranthus and is the sole member of a new section within L. subg. Lampranthus. The two larger sections of L. subg. Lampranthus show different evolutionary trends and distributions: Lampranthus sect. Lampranthus contains more species, they are mostly in the winter rainfall region of the Western Cape and they have a greater range of floral shapes and colours. Lampranthus sect. Blandi contains a single species in the Kamiesberg, in the Northern Cape, while most of its species occur along the southern coast of southern Africa eastwards to southern Natal. These species are florally less diverse. Two species of Lampranthus are moved to a new genus, Malephoropsis gen. nov. These are unrelated to the rest of Lampranthus and they fall among species of Malephora, Disphyma and Gibbaeum with which they share softly corky branches, mesomorphic leaves and only slightly woody fruits with false septa. Several species, which were at one stage included in Lampranthus, are re‐instated in Ruschia; for four others, previously transferred out of Lampranthus to Esterhuysenia or Oscularia, but which cannot be accommodated into any of the existing genera, we propose a new genus, Sederbergia gen. nov. Lastly, we consider three monotypic genera which were sequenced here for the first time: Circandra is re‐instated in Erepsia; Malotigena is transferred to Delosperma subg. Proterogyna; the relationships of Daggodora remain unresolved.