Kenneth Bauters

An integrative approach to understanding the evolution and diversity of Copiapoa (Cactaceae), a threatened endemic Chilean genus from the Atacama Desert

PREMISE OF THE STUDY Species of the endemic Chilean cactus genus Copiapoa have cylindrical or (sub)globose stems that are solitary or form (large) clusters and typically yellow flowers. Many species are threatened with extinction. Despite being icons of the Atacama Desert and well loved by cactus enthusiasts, the evolution and diversity of Copiapoa has not yet been studied using a molecular approach. METHODS Sequence data of three plastid DNA markers (rpl32-trnL, trnH-psbA, ycf1) of 39 Copiapoa taxa were analyzed using maximum likelihood and Bayesian inference approaches. Species distributions were modeled based on geo-referenced localities and climatic data. Evolution of character states of four characters (root morphology, stem branching, stem shape, and stem diameter) as well as ancestral areas were reconstructed using a Bayesian and maximum likelihood framework, respectively. KEY RESULTS Clades of species are revealed. Though 32 morphologically defined species can be recognized, genetic diversity between some species and infraspecific taxa is too low to delimit their boundaries using plastid DNA markers. Recovered relationships are often supported by morphological and biogeographical patterns. The origin of Copiapoa likely lies between southern Peru and the extreme north of Chile. The Copiapó Valley limited colonization between two biogeographical areas. CONCLUSIONS Copiapoa is here defined to include 32 species and five heterotypic subspecies. Thirty species are classified into four sections and two subsections, while two species remain unplaced. A better understanding of evolution and diversity of Copiapoa will allow allocating conservation resources to the most threatened lineages and focusing conservation action on real biodiversity.

Phylogenetics, ancestral state reconstruction, and a new infrageneric classification of Scleria (Cyperaceae) based on three DNA markers

The genus Scleria (Cyperaceae), with ca. 250 species, is placed in the monotypic tribe Sclerieae. It has a primarily pantropical distribution. Previously, infrageneric classifications have been proposed but none has been based on molecular phylogenetic evidence and most studies have treated the genus from only one geographical region. In this study, DNA portions from 101 species of Scleria from across its distributional range and all infrageneric groups were extracted and amplified for three molecular markers: the coding chloroplast marker ndhF, the chloroplast intron rps16 and the nuclear ribosomal region ITS. Phylogenetic hypotheses were constructed using Bayesian inference and maximum likelihood approaches. Additionally, ancestral states of four morphological characters were reconstructed at important nodes using the program BayesTraits. A new infrageneric classification based on molecular evidence and supported by morphology is presented. Scleria is confirmed as monophyletic and sister to tribe Bisboeckelereae. A subdivision of Scleria into four subgenera (S. subg. Browniae, S. subg. Hypoporum, S. subg. Scleria, S. subg. Trachylomia) is supported by our results. In this paper, twelve major clades are recov- ered within Scleria subg. Scleria. Clear morphological diagnostic features match these clades. Ancestral state reconstruction indicates that androgynous spikelets, a zoniform hypogynium, a paniculate inflorescence with staminate and subandrogynous spikelets, and normal linear leaves are ancestral in Scleria. Androgynous spikelets are found in the three first-branching subgenera, while in S. subg. Scleria an evolutionary shift towards subandrogynous and strictly unisexual spikelets is noted. Hypogynia are generally well developed with the exception of S. subg. Hypoporum, where the hypogynium is reduced or even lost. Inflorescences in Scleria vary from short, densely paniculate and pyramidal to subcapitate, only in S. subg. Hypoporum a glomerate-spicate inflorescence is found. The pseudopremorse leaf habit arose only once within S. subg. Scleria. Scleria sect. Scleria shows a reversal to normal leaf tips.

Molecular phylogenetic study of Scleria subgenus Hypoporum (Sclerieae, Cyperoideae, Cyperaceae) reveals several species new to science

Scleria subgen. Hypoporum (Cyperaceae), with 68 species, is the second largest subgenus in Scleria. Species of this pantropically distributed subgenus generally occur in seasonally or permanently wet grasslands or on shallow soils over sandstone or lateritic outcrops, less often they can be found in (open) woodlands. Previous studies established the monophyly of the subgenus, but the relationships between the species remained uncertain. In this study, DNA sequence data of 61 taxa of Scleria subgen. Hypoporum, where possible represented by multiple accessions from across their distributional range, were obtained for four molecular markers: the coding chloroplast marker ndhF, the chloroplast intron rps16 and the nuclear ribosomal regions ETS and ITS. Phylogenetic trees were constructed using Bayesian inference and maximum likelihood approaches. A species tree was constructed to summarise the results. The results indicate the existence of three sections: the monotypic, pantropically occurring, Scleria sect. Lithospermae, a new section from central and south America containing two species, and Scleria sect. Hypoporum, also pantropically distributed, containing the remainder of the species of the subgenus. Relationships in the latter section are not fully resolved. However, three or four different clades can be distinguished supported by some morphological characters. Our results indicate at least six new species in Scleria sect. Hypoporum. The new section and species are described in a taxonomical treatment. Their morphology is compared with (morphologically) closely related species.

Scleria cheekii , a new species of Scleria subgenus Hypoporum (Cyperaceae, Cyperoideae, Sclerieae) from Cameroon

SummaryAn endemic species of Scleria (Cyperaceae) from Cameroon, Scleria cheekii Bauters, is described as new to science. Scleria cheekii is an annual known from basalt pavements in the Bamenda Highlands in Cameroon. It can be distinguished from related species by the presence of tuberculated yellow-orange translucent tissue covering the trigonous stipe. This species is described, illustrated and compared with morphologically closely allied species.

Phylogeny and Systematics of Cyperaceae, the Evolution and Importance of Embryo Morphology

Despite recent advances in molecular phylogenetic studies, deep evolutionary relationships in Cyperaceae are still not entirely resolved. Reduction of floral morphology and complex inflorescences pose difficulties to unravel relationships based on morphology alone. One of the most phylogenetically informative structures in Cyperaceae are the embryos. The utility of embryo characters and types in Cyperaceae systematics is reviewed in a molecular phylogenetic context using a DNA supermatrix incorporating sequences from five plastid (matK, ndhF, rbcL, rps16, trnL-F) and two nuclear ribosomal (ETS, ITS) regions. The phylogenetic hypothesis presented includes the most extensive sampling of the family to date. Fourteen qualitative morphological embryo characters were coded, ancestral state reconstructions were performed, and the embryo of each sampled genus was classified in a typological system based on key morphological features. Embryo morphology provides a valuable source of independent data for Cyperaceae systematics that can be used to place species with unknown affinities, when molecular data is not available, or when results of analyses are inconclusive or conflicting. Integrating embryo data will remain critical for future higher level studies of Cyperaceae evolution and classification.

Cyperus albescens, a new combination in Cyperus (Cyperaceae) for the common (sub)tropical African and Asian species Lipocarpha chinensis

SummaryThe replacement name Cyperus lipocarpha T. Koyama published in 1960 for Lipocarpha chinensis (Osbeck) J. Kern is incorrect, because an earlier epithet of a heterotypic name is available for combination in Cyperus. A new combination, Cyperus albescens (Steud.) Larridon & Govaerts is here proposed.

Two New Species of Cyperus (Cyperaceae) from the Zambezian Region of Africa

Abstract Cyperus absconditicoronatus Bauters, Reynders & Goetgh. and C. unispicatus Bauters, Reynders & Goetgh., two new species of Cyperus L. (Cyperaceae) from Angola and Zambia, are recognized. Cyperus absconditicoronatus is a tall species (55–100 cm) characterized by a scaled rhizome, a single terminal capitulum, a ciliated spikelet bract, and deciduous spikelets. Cyperus unispicatus can be recognized by a swollen and fibrous stem base growing from slender rhizomes, a single terminal spike, and short involucral bracts. The taxa are described and illustrated, and differences with the closest resembling species are discussed.