An integrative monograph of Carex section Schoenoxiphium (Cyperaceae)

Abstract

Carex section Schoenoxiphium (Cariceae, Cyperaceae) is endemic to the Afrotropical biogeographic region and is mainly distributed in southern and eastern Africa, with its center of diversity in eastern South Africa. The taxon was formerly recognized as a distinct genus and has a long history of taxonomic controversy. It has also an important morphological and molecular background in particular dealing with the complexity of its inflorescence and the phylogenetic relationships of its species. We here present a fully updated and integrative monograph of Carex section Schoenoxiphium based on morphological, molecular and cytogenetic data. A total of 1,017 herbarium specimens were examined and the majority of the species were studied in the field. Previous molecular phylogenies based on Sanger-sequencing of four nuclear and plastid DNA regions and RAD-seq were expanded. For the first time, chromosome numbers were obtained, with cytogenetic counts on 44 populations from 15 species and one hybrid. Our taxonomic treatment recognizes 21 species, one of them herein newly described (C. gordon-grayae). Our results agree with previous molecular works that have found five main lineages in Schoenoxiphium. We provide detailed morphological descriptions, distribution maps and analytical drawings of all accepted species in section Schoenoxiphium, an identification key, and a thorough nomenclatural survey including 19 new typifications and one nomen novum.

An Evolutionary Study of Carex Subg. Psyllophorae (Cyperaceae) Sheds Light on a Strikingly Disjunct Distribution in the Southern Hemisphere, With Emphasis on Its Patagonian Diversification

“…The monophyly of sect. Schoenoxiphium is well-supported (Clade B1; Supplementary Figure 5), which agrees with previous studies focusing on that group (Luceño et al, 2021, and references therein) despite resolution problems reported for its inner phylogenetic structure. Meanwhile, C. camptoglochin and C. phalaroides are nested within sect.…”

“…Schoenoxiphium was inferred to have originated in the Drakensberg range in South Africa, where its current center of diversity is still located (Márquez-Corro et al, 2020 ). In this area, species distributions are often overlapping, but with frequent turnover along various ecological gradients (elevation, wetness, forest to grassland; Luceño et al, 2021 ). Thus, speciation in this lineage appears to have been sympatric and driven by ecological factors.…”

“…Psyllophorae ; and 17 included in sect. Schoenoxiphium (all except C. acocksii C. Archer, C. chermezonii Luceño and Martín-Bravo, C. gordon-grayae Luceño, Márq.-Corro and Sánchez-Villegas, and C. sciocapensis Luceño, Márq.-Corro and Sánchez-Villegas; see Luceño et al, 2021 for more information). Our dataset comprises 87% of all the extant diversity known for subg.…”

Cyperaceae in a data‐rich era: New evolutionary insights from solid frameworks

“…Confertiflorae and Molliculae-and provide the first insights into Carex phylogeography in Eastern Asia. These examples show the strength of combining multiple data sources to investigate the evolution and diversity of Cyperaceae lineages and it demonstrates that considerable work is still needed on understudied lineages and geographic regions, as also found by recent studies in other sedge groups (e.g., Jiménez-Mejías et al, 2021;Luceño et al, 2021). Using population genomics based on RADseq data and ecological niche modeling, Nygaard et al (2021) found that Carex jemtlandica and C. lepidocarpa in Carex sect.…”

“…As such, we are moving toward solving the long-standing questions about taxon limits within this species complex, a problem evaluated multiple times using Sanger sequencing (Jiménez-Mejías et al, 2012 and allozyme variation (Hedrén & Prentice, 1996;Hedrén, 2002Hedrén, , 2004Blackstock, 2007) without clear resolution. Population genomics using GBS, RADseq, or targeted sequencing methods offer hope to tackle many more species complexes in future, as has already been shown in previous research efforts on sedges (Escudero et al, 2014;Maguilla et al, 2017;Léveillé-Bourret et al, 2020;Luceño et al, 2021).…”