The inflorescences structure of Cyperus L. section Luzuloidei Kunth (Cyperaceae)

In the present work the inflorescences of 12 species of Cyperus sect. Luzuloidei Kunth sensu Kükenthal were analyzed using the methodology and terminology of Troll's school. All the inflorescences studied are polytelic (indeterminate). The inflorescences are anthela-like or capitate, and can be terminal or pseudolateral. Below the main florescence a paracladial zone is present. In this zone three types of branching were observed, i.e. normal, accessory-axillar and prophyllar branching, whose position vary among the different species. In the paracladial zone a subzone of long paracladia and a subzone of short paracladia were observed. In the short paracladial subzone the spikelets are clustered in fascicles, which can be serial, prophyllar or mixed. Variation in length and position of pherophylls, length of prophyll, number and degree of branching were noticed. The systematic value of the inflorescences in the section Luzuloidei is discussed.     

Phylogenetic relationships in Cyperus L. s.l. (Cyperaceae) inferred from plastid DNA sequence data

The phylogeny of Cyperus and allied genera has been reconstructed using cladistic analysis of plastid rbcL gene, rps16 intron, trnL intron, and trnL-F intergenic spacer sequence data in 40 species of tribe Cypereae. Cyperus s.s. as currently circumscribed is not monophyletic because ten cyperoid genera are embedded within it. Eucyperoid Cyperus species (with a C₃ anatomy, e.g. C. involucratus ) and the genera Courtoisina , Kyllingiella and Oxycaryum form a clade that is sister to a clade comprising chlorocyperoid species (with a C₄ anatomy, e.g. C. papyrus ) and the genera Alinula , Ascolepis , Kyllinga , Lipocarpha , Pycreus , Remirea and Sphaerocyperus . The position of two species is uncertain; C . tenellus is resolved in a clade together with Isolepis although with typical cyperoid spikelets, whereas I. humillima is not resolved near either Isolepis or Cyperus s . l . © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 138 , 145–153.     

Typification of names in Cyperus section Arenarii (Cyperaceae)

The typification of names in the genus Cyperus was done as part of an ongoing study of the section Arenarii. The latest monograph on the genus by Kükenthal (1936), accepted eight species in the section Bobartia (= Arenarii ), and a number of lower level taxa, which are treated here either as distinct species or synonyms. The taxonomic treatment of the core species, C. conglomerates Rottb., turned out to be especially confusing, which is reflected in the past identifications of the material, and consequently, has created wrong interpretations on the distributions. C. jeminicus Rottb. has similarly caused a lot of confusion. Currently we recognize 26 species in the section, with two subspecies in C. conglomerate. Most names in the section have not earlier been typified. Here we designate lectotypes for 33 names, three epitypes, and one neotype. Cyperus sections Arenarii Kunth and Hymenolepides Nees are typified also.     

Phylogenetic position of Cyperus clandestinus (Cypereae,Cyperaceae) clarified by morphological and molecular evidence

Extreme morphological reduction and convergent evolution can obscure taxonomic relationships. This phenomenon is frequently encountered in Cyperaceae, where characters traditionally used to diagnose genera have been shown to have evolved independently multiple times. The Ethiopian high‐altitude perennial first described as Cyperus clandestinus was subsequently moved to Ficinia because it has spiral glume arrangement, unlike typical Cyperus species, which have distichous glume arrangement. However, this position has remained uncertain as no nutlets have previously been studied to establish the presence or absence of the gynophore – the synapomorphy for Ficinia. We resolve this 140‐year‐old puzzle by describing the morphology of the nutlet, which lacks a gynophore, and use DNA sequence data to resolve the taxon within Cyperus. Cyperus clandestinus was found to be closely related to Remirea maritima and Cyperus cyperoides in the C₄Cyperus clade, whose members predominantly have distichously arranged glumes. This provides further evidence for the unreliability of glume arrangement as a character to distinguish between members of the Cyperus and Ficinia clades, whereas gynophore presence is more congruent with molecular data.     

Eight new species of Cyperus (Cyperaceae) from Somalia

Eight new species and one new subspecies of Cyperus subgen. Cyperus (including Mariscus ) are described, illustrated and mapped, viz. C. densibulbosus, C. scabricaulis, C. pluricephalus, C. baobab, C. micromedusaeus, C. gypsophilus, C. somalidunensis, C. recurvispicatus and C. rotundus ssp. divaricatus .     

Towards a new classification of the giant paraphyletic genus Cyperus (Cyperaceae): phylogenetic relationships and generic delimitation in C4 Cyperus

Maximum likelihood and Bayesian inference analyses of nuclear ribosomal DNA (ETS1f) and plastid DNA (rpl32‐trnL, trnH‐psbA) sequence data are presented for ‘C₄ Cyperus’ (Cyperaceae). The term ‘C₄ Cyperus’ encompasses all species of Cyperus s.l. that use C₄ photosynthesis linked with chlorocyperoid vegetative anatomy. Sampling comprises 107 specimens of 104 different taxa, including many of the subdivisions of C₄ Cyperus s.s. and all C₄ segregate genera (Alinula, Ascolepis, Kyllinga, Lipocarpha, Pycreus, Queenslandiella, Remirea, Sphaerocyperus and Volkiella). According to our results, C₄ Cyperus is a well‐supported monophyletic clade nested in C₃ Cyperus. Despite the lack of resolution along the backbone of the C₄ Cyperus clade and for some internal branches, several well‐supported clades can be distinguished. The first clade in C₄ Cyperus is formed by Cyperus cuspidatus and C. waterloti. Other recognizable and well‐supported clades correspond to segregate genera, i.e. Ascolepis, Lipocarpha including Volkiella, and Kyllinga. Species of C₄ Cyperus s.s. form a core grade in which the C₄ segregate genera are embedded. Pycreus, the largest segregate genus composed of c. 120 species, is not monophyletic as it includes several C₄ species of Cyperus s.s. This study establishes a phylogenetic framework for revising the classification and character evolution in Cyperus s.l. © 2013 The Linnean Society of London     

Multiple origins of XY female mice (genus Akodon): phylogenetic and chromosomal evidence

Despite the diversity in sex determination across organisms, theory predicts that the evolution of XY females is rare in mammals due to fitness consequences associated with infertility or the loss of YY zygotes. We investigated this hypothesis from a phylogenetic perspective by examining the inter- and intraspecific distribution of Y chromosomes in males and females (XY females) in South American field mice (Akodon). We found that XY females occurred at appreciable frequencies (10-66%) in at least eight Akodon species, raising the possibility that this system of sex determination has arisen multiple times independently. To determine the number of origins of XY females in Akodon, we constructed a molecular phylogeny of 16 species of Akodon based on mitochondrial DNA control region sequences. Both parsimony and maximum-likelihood reconstruction of ancestral states suggest that multiple steps (gains or losses of XY females) best explain the evolution of XY females, but do not clearly differentiate between single and multiple origins. We then directly compared functional and non-functional Y chromosomes in six species by Southern blot analysis. We found that male and female Y chromosome restriction fragment length polymorphism patterns were identical within species, but always differed between species, providing evidence that XY females arose at least six times within the Akodon lineage. To our knowledge, this pattern in Akodon is the first documentation of a novel sex-determining system arising multiple times within a tight clade of mammals. In addition, this system provides a clear test of the accuracy of phylogenetic methods to reconstruct ancestral states.     

Studies in African Cyperaceae 18. Two new subgenera of Cyperus

Two new subgenera are described and illustrated. Cyperus subgen. Protocyperus has an eucyperoid culm–anatomy and digitate clusters of spikelets. It contains about 100 species. Cyperus subgen. Fimbricyperus has a chlorocyperoid culm anatomy and many stalked spikes giving the habit of a slender Fimbristylis. It is based on a single species, viz. Cyperus subparadoxus Kükenthal.     

Studies in African Cyperaceae 25. New taxa and combinations in Cyperus L.

Four new subgenera, nineteen new species, two new subspecies and two new varieties of Cyperus L. are described, viz. subgen. Aristomariscus Lye, subgen. Bulbomariscus Lye, subgen. Xerocyperus Lye, subgen. Micromariscus Lye, Cyperus micromariscus Lye, C. boreochrysocephalus Lye, C. crassivaginatus Lye, C. kyllingaeformis Lye, C. cremeomariscus Lye, C. gigantobulbes Lye, C. boreobellus Lye, C. longi–involucralus Lye, C. kwaleensis Lye, C. afrovaricus Lye, C. afrodunensis Lye, C flavoculmis Lye, C microumbellatus Lye, C. purpureoviridis Lye, C. graciliculmis Lye, C. afromon–tanus Lye, C. nyererei Lye, C. afroalpinus Lye, C castaneobellus Lye, C. soyauxii Boeck. ssp. pallescens Lye, C. usitatus Burch. ssp. palmatus Lye, C. renschii Boeck. var. scabridus Lye, and C. fischerianus A. Rich. var. ugandensis Lye. The following new combinations are made: Cyperus L. subgen. Bulbocaulis (C.B.C1.) Lye, Cyperus L. subgen. Courtoisia (Nees) Lye, Cyperus L. subgen. Sorostachys (Steudel) Lye, Cyperus L. subgen. Remirea (Aublet) Lye, Cyperus L. subgen. Alinula (Raynal) Lye, Cyperus lipocarphoides (Kükenth.) Lye, C. malawicus (Raynal) Lye, C. tanganyica–nus (Kiikenth.) Lye, C. mortonii (Hooper) Lye, C. pseudodiaphanus (Hooper) Lye, C. overlaetii (Hooper & Raynal) Lye, C. dewildeorum (Raynal) Lye, C. pagotii (Raynal) Lye, C. demangei (Raynal) Lye, C. afroechinatus Lye, C. niveus Retz. var. ledermannii (Kiikenth.) Lye, C. niveus Retz. var. tisserantii (Cherm.) Lye, C. distans L.f. ssp. longibracteatus (Cherm.) Lye, C. distans L.f. ssp. longibracteatus (Cherm.) Lye, var. rubrotinctus (Cherm.) Lye, C. cyperoides (L.) Kuntze ssp. alternifolius (Vahl) Lye, C. cyperoides (L.) Kuntze ssp. macrocarpus (Kunth) Lye, C. cyperoides (L.) Kuntze ssp. pseudoflavus (Clarke) Lye, C. dubius Rottb. ssp. macrocephalus (Kiikenth.) Lye, C. dubius Rottb. ssp. coloratus (Vahl) Lye, C. usitatus Burch. var. stuhlmannii (Clarke) Lye, C. laxus Lam. ssp. sylvestris (Ridley) Lye, and C. laxus Lam. ssp. buchholzii (Boeck.) Lye and C. globifer (Clarke) Lye.     

The systematic anatomy of south Indian Cyperaceae: Cyperus L. subgen. Juncellus, Cyperus subgen. Mariscus and Lipocarpha R. Br.

The three investigated species of Cyperus L. subgen. Juncellus (Griseb.) C. B. Clarke show anatomical differences in the leaf pertaining to the number of vascular bundles and bundle sheaths, size of silica-cells and their wall thickness, while those of subgen. Mariscus (Gaertner) C. B. Clarke segregate into two primary groups depending on the presence or absence of a distinct hypodermis; and the species within each group are further differentiated on the basis of the presence or absence of air-cavities, the number of vascular bundles and their pattern of arrangement in the leaf. The interspecific differences observed within the genus Lipocarpha R. Br. concern the size of the interstomatal cells and the number of vascular bundles and bundle sheaths of the leaf. Keys for the identification of the species in each genus and subgenus are given separately.     

Studies in African Cyperaceae 38: Cyperus inselbergensis sp. nov. from inselbergs in Gabon and Cameroun

Cyperus inselbergensis Lye is described from northern Gabon and adjacent Cameroun. It has a very characteristic ecology as it grows in seasonally wet, shallow soils on or close to inselbergs. The species belongs to Cyperus subgen. Kyllinga and is most similar to C. triceps, but differs in its hemispherical inflorescence, smaller spikelets, different glumes with scabrid midrib, and smaller fruits. The species is widespread and locally common in its restricted habitat.     

Developmental origins of structural diversity in pollen walls of Compositae

Compositae exhibit some of the most complex and diverse pollen grains in flowering plants. This paper reviews the evolutionary and developmental origins of this diversity in pollen structure using recent models based on the behaviour of colloids and formation of micelles in the differentiating microspore glycocalyx and primexine. The developmental model is consistent with observations of structures recovered by pollen wall dissolution. Pollen wall diversity in Compositae is inferred to result from small changes in the glycocalyx, for example ionic concentration, which trigger the self-assembly of highly diverse structures. Whilst the fine details of exine substructure are, therefore, not under direct genetic control, it is likely that genes establish differences in the glycocalyx which define the conditions for self-assembly. Because the processes described here for Compositae can account for some of the most complex exine structures known, it is likely that they also operate in pollen walls with much simpler organisation.     

Allozyme variation and racial differentiation in Swedish Carex lepidocarpa s.l. (Cyperaceae)

Two morphological races have previously been recognized within the sedge, Carex lepidocarpa , in Sweden. These largely allopatric races are accorded specific status, as C. lepidocarpa s.s. and C. jemtlandica , in Scandinavian floras. A study of allozyme variation in populations from 80 Swedish sites supports the morphological evidence for racial differentiation within C. lepidocarpa. The two races differ from each other in terms of allele frequencies at polymorphic loci and also show different levels of within-population genetic diversity. Material that is morphologically referable to C. lepidocarpa s.s. is characterized by relatively high levels of allozyme variation, both within and between populations. Carex lepidocarpa s.s. is widespread in southern Sweden. In contrast, material that is morphologically assignable to C. jemtlandica shows low levels of within-population genetic diversity, and there is little differentiation between the geographically separated isolates of C. jemtlandica in northern Sweden and on the Baltic island of Gotland. The high degree of morphological similarity and moderate levels of genetic differentiation between the two races within C. lepidocarpa indicate that it is more appropriate to recognize the races as subspecies than as species. The low levels of genetic variation in C. jemtlandica , both within and between populations, suggest that C. jemtlandica may have arisen from C. lepidocarpa (or a near ancestor of C. lepidocarpa) as a result of population fragmentation and isolation in glacial refugia, or during the process of post-glacial colonization of Scandinavia. Lack of allozyme evidence for extensive hybridization between the two races of C. lepidocarpa , despite their ability to hybridize freely where their ranges overlap at present, supports the suggestion that the two races have had separate post-glacial histories.     

The past,present and future of thermophilous Cyperus polystachyos Rottb. (Cyperaceae) on the island of Ischia (southern Italy)

Cyperus polystachyos is a hygrophilous, thermophilous and heliophilous plant with a punctiform distribution in southern Italy, where it is almost exclusively found on Ischia, an island in the Bay of Naples characterized by widespread volcanic hydrothermal activity. This species is a native of tropical and subtropical areas and there is evidence for ancient isolation events in the creation of its current distribution pattern. We have studied the historical literature available for this plant since 1800 and collected temporal and spatial presence data of this species in order to develop a habitat suitability map based on a GIS approach and using a multiple linear regression model. Moreover, we have used univariate and multivariate statistical analysis. The results show the importance of the environmental mosaic around fumaroles to preserve the species; urbanization and geothermal energy use of fumaroles in the past and the combination of abandonment of the typical agricultural system and the natural occurrence of reforestation in the present are the main causes of the decline in the number of populations.     

Affinities in C3Cyperus lineages (Cyperaceae) revealed using molecular phylogenetic data and carbon isotope analysis

Maximum likelihood and Bayesian analyses of nrDNA (ETS1f) and plastid DNA (rpl32‐trnL, trnH‐psbA) sequence data are presented for ‘C₃Cyperus’ (Cyperaceae). The term ‘C₃Cyperus’ indicates all species of Cyperus s.l. that use C₃ photosynthesis linked with eucyperoid vegetative anatomy. Sampling comprises 77 specimens of 61 different taxa, representing nearly all previously recognized subdivisions of C₃Cyperus and the segregate genera Courtoisina, Kyllingiella and Oxycaryum. According to our results, the Cyperus clade is divided in six well‐supported clades. The first of these clades (clade 1) forms three subclades largely corresponding to Cyperus sections Haspani, Incurvi and Diffusi. Clade 2 comprises the entirely New World C. section Luzuloidei sensu Denton (1978). Clade 3 is a highly diverse clade including two subclades: clade 3a, C. sections Pseudanosporum and Anosporum plus the segregate genera Courtoisina and Oxycaryum; and clade 3b, C. section Fusci. Clade 4 corresponds to C. section Alternifolii and clade 5 to C. section Leucocephali plus the segregate genus Kyllingiella. The sixth clade is a well‐supported monophyletic clade encompassing all C₄Cyperus s.l. species (‘C₄Cyperus’). This study establishes a phylogenetic framework for future studies. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167 , 19–46.     

Leaf anatomical characters in relation to the C3 and C4 photosynthetic pathway in Cyperus (Cyperaceae)

Leaf anatomical characters of twelve species from the genus Cyperus, a genus known to contain species with both C₃ and C₄ plants, have been investigated. We investigated and established the usefulness of all‐inclusive functional leaf anatomical characters for identifying the photosynthetic pathways of these species. The species investigated were C. articulatus L., C. compressus L., C. difformis L., C. dilatatus Schum. & Thonn., C. distans L., C. esculentus L., C. haspan L., C. imbricatus Retz., C. iria L., C. rotundus L., C. sphacelatus Rottb. and C. tenuiculmis (Boeck.) Hooper, collected from locations in southwestern Nigeria. Standard anatomical procedures for examining epidermal and cross sections of leaves were employed. Our data suggested that a combination of characters, such as the occurrence of Kranz tissue, maximum cell distant count, maximum lateral cell count, interveinal distance, and to some extent leaf and mesophyll thickness, provide a reliable basis for the assessment of the photosynthetic pathways of the investigated species as compared to the isolated characters used previously. The study indicate that C. difformis and C. haspan are C₃ species while the rest follow the C₄ photosynthetic pathway. A salient feature of this study is the identification of C. dilatatus as belonging to the C₄ group.     

A molecular survey concerning the origin of Cyperus esculentus (Cyperaceae,Poales): two sides of the same coin (weed vs. crop)

Background and AimsCyperus esculentus is widespread in tropical and temperate zones and is also present in cooler regions. It is used as a crop plant, but it also occurs in the wild and as a weed. As a consequence of its ecological plasticity, C. esculentus has remarkable variability, with several morphotypes. Four wild-type varieties are presently recognized, in addition to the cultivated form. This study investigates the phylogenetic position and biogeography of C. esculentus with the objective of contributing new data to increase the understanding of its evolutionary history.Methods Genealogical relationships among genotypes were inferred by using plastid DNA haplotype and nuclear ribosomal (nr) DNA ribotype sequences for 70 specimens either collected in the field or obtained from herbaria. Statistical dispersal–vicariance (S-DIVA) and Bayesian binary method (BBM) analyses were used to reconstruct the possible ancestral ranges of C. esculentus. In order to determine the age of C. esculentus, a time-measured phylogenetic analysis was performed.Key Results Considerable variation between the chosen nuclear and plastid markers was detected (27 ribotypes vs. six haplotypes). No geographical structure was displayed among the haplotypes, but information on the dispersal pattern may be deduced. Two types of ribotypes were detected in nrDNA, with an evident geographical segregation into an Old World group and a polymorphic New World group. Both S-DIVA and BBM analyses suggested a biogeographical history in which dispersal from the African region has been crucial in shaping the current distribution pattern of C. esculentus. The most recent common ancestor between C. esculentus races has an age of 5.1 million years (95 % highest posterior density 2.5–10.2).Conclusions The molecular analysis provides novel insights into the evolutionary history of C. esculentus. The results have various taxonomic and phylogenetic implications, including a hypothesis on the origin and phylogeography of this species, which probably originated in the late Cenozoic in Africa, and reached the Americas repeatedly, independently of Columbian exchanges.