Search

• This is the first study on the floral morphology and anatomy of Mesanthemum. • The type of petal fusion of Mesanthemum may be related to space constraints. • M. radicans distinguishes by the presence of three vascular bundles in the petals. • Short outer stamens may be a step towards their loss in Paepalanthoideae. • Petal glands and carpellodes show diagnostic features for Eriocaulaceae. Mesanthemum is a genus of Eriocaulaceae endemic to Africa whose petals are free at the base and fused from the middle region up to the apex. Detailed studies on its floral morphology are scarce and based only on exsiccates, while the floral anatomy remains understudied. However, information regarding its floral structure is key to understanding the evolution of Eriocaulaceae. We provided details on the floral morphology and anatomy of M. radicans to evaluate characters with taxonomic and evolutionary importance. The flowers of M. radicans have tightly packed floral parts and reduced vasculature. They have petals with three vascular bundles, in contrast to a single bundle in petals of other Eriocaulaceae. Each petal receives three vascular traces, as in Xyridaceae, but they diverge from common petal-inner stamen traces. The type of petal fusion and the presence of stamens at two heights in M. radicans are probably related to space constraints in the floral buds of this species. However, further studies are necessary to comprehend the developmental processes that lead to petal fusion in Mesanthemum. The fact that the outer stamens are shorter than the inner ones can be interpreted as a step towards their loss in Paepalanthoideae. Furthermore, the petal glands and the carpellodes share characteristics, such as shape and the presence and location of papillae, that may be diagnostic for Eriocaulaceae. [ABSTRACT FROM AUTHOR]

Understanding how climate change will affect regeneration from seeds is important for developing conservation strategies. We evaluated seed germination requirements for sympatric species of Xyris from montane rupestrian grasslands (campo rupestre) in Brazil to determine their thermal niche and thermal requirements for seed germination. We also assessed whether projected temperature increases would affect seed germination of the species. Seed germination was evaluated at a wide range of constant temperatures (10–40°C) under light (12‐hr photoperiod) and dark conditions. Base temperatures (Tb) and thermal times for 50% germination (θ50) were calculated for three species. The effects of projected mean temperature increase on seed germination percentage and timing were evaluated. All species revealed an absolute light requirement for germination. Thermal germination niche breadth was greatest for X. asperula (15 to 35°C) and narrowest for X. seubertii (20 and 25°C). Base temperatures for X. asperula, X. pilosa and X. trachyphylla were 9.0, 12.8 and 11.1°C, respectively. In the scenario with the highest temperature increase (A2), the greatest reductions in seed germination are observed for X. pilosa and X. seubertii. The lowest projected temperature increase (2°C) was sufficient to decrease by 1 day the germination time of X. asperula and X. pilosa. Species of Xyris do not present a pattern for thermal germination niche and thermal requirements values, indicating that the effects of climate warming on the regeneration of these seeds will probably vary among species. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Xinyang Normal University Natural Science Edition is the property of Journal of Xinyang Normal University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Germination ecology was investigated in a natural population of Xyris longiscapa, a perennial herbaceous species endemic to the Brazilian campo rupestre. Seeds were collected over four consecutive years (2014 to 2017) to evaluate germination responses to a range of temperatures (from 15 to 30°C). The light requirement was evaluated in seeds collected in 2014. Seeds collected in 2014 were also buried in soil in the natural habitat of the species to evaluate changes in germinability at different temperatures over the time. Seeds showed an absolute light requirement for germination. Seed germination was affected by temperature, collection year and the interaction between these two factors. Seeds collected in 2014 showed a narrower temperature range for germination (15–20°C), compared with the seeds collected in 2015, 2016 and 2017 that germinated in a temperature range of 15–25°C. Buried seeds remained viable in soil for at least 14 months and exhibited seasonal dormancy cycling. Secondary dormancy was induced during the rainy season and alleviated during the dry season, following a conditional dormancy/dormancy cycle. The degree of primary dormancy appeared to be influenced by the environmental conditions experienced by seeds during maturation. Primary dormancy (when present), seed persistence in soil and seasonal dormancy cycles are strategies of X. longiscapa to enhance regeneration success in the harsh environment of the Brazilian campo rupestre. [ABSTRACT FROM AUTHOR]

Copyright of Geominas is the property of FUNDA-GEOMINAS. (Fundacion de Egresados d Amigos de la Escuela de Ingenieria Geologica y de Minas) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Xyris irwinii (Xyridaceae), a new species from the cerrado of Goiás, Brazil is described and illustrated. The distribution, phenology, and conservation status of the new species are presented, as well as a comparison of a complex of morphologically related cerrado species. [ABSTRACT FROM AUTHOR]

Abstract: Aim: Climate tends to explain phenological variations in tropical ecosystems. However, water availability and nutrient content in soil strongly affect plant communities, especially those on old, climatically buffered, infertile landscapes (OCBILs), and may impact these ecosystems’ plant reproductive phenology over time. Here, we compare the reproductive phenology of sandy and stony tropical grasslands, two co‐occurring herbaceous communities of the campo rupestreOCBILs. We asked whether flowering, fruiting and dispersal are seasonal in both grasslands, and whether these phenophases differ due to variations in soil properties. We also asked whether the phenological strategies and the number of flowers and fruits differ between these two grasslands as soil conditions vary. Location: Serra do Cipó, Minas Gerais, Brazil. Methods: The phenology of herbaceous species of sandy and stony grasslands was monitored monthly over two consecutive years. Results: Plants on sandy and stony grasslands flowered and fruited throughout the year. We did not find a distinct seasonal pattern at the community level of either studied grassland. However, flowering, fruiting and seed dissemination occurred in stony grasslands mainly during the rainy season, while sandy grassland species flowered in both seasons and fruited and disseminated seed mainly during the dry season, as observed in other savanna vegetation types in the Cerrado. Flower and fruit production was higher in sandy grasslands than in stony grasslands, which may be linked to higher water retention in sandy grassland soils. In both communities, species of Cyperaceae, Eriocaulaceae and Xyridaceae contributed most to overall production, whereas Poaceae and Velloziaceae, two important families in campo rupestre, barely participated in the reproductive phenology during our 2‐yr survey. Conclusions: Despite a strong seasonal climate, there was no reproductive seasonal pattern at the community level in campo rupestre. This first investigation of Neotropical grassland phenology indicates that the differences in soil content may constrain the grassland reproductive phenology and restrict reproduction of stony grassland species to the most favourable season. Further studies of grassland phenology are necessary to disentangle the relative importance of soil, climate and other triggers, especially fire. [ABSTRACT FROM AUTHOR]

Campo rupestre is a fire-prone ecosystem with marked seasonality. In this work, we evaluated the effects of two recurrent stressors in campo rupestre on seed germination of two typical perennial herbs – Xyris asperula and X. trachyphylla . Heat shock at different temperatures and exposure times were used to simulate fire passage, and desiccation of germinating (imbibed) seeds was used to simulate drought. The aim of this study was to evaluate the tolerance (based on germination) of seeds subjected to these stressors. Seeds of both species showed a significant tolerance to heat shock. Exposure at 100 °C for any amount of exposure time does not affect seed germination. Decrease in germinability (seed death) became more evident only at 180 °C. Water uptake by seeds was fast, and slow drying for 48 h does not affect the germination of seeds imbibed for 24, 48, 72 or 96 h. Similarly, slow or fast drying for up to eight days did not cause changes in seed germination. Our results demonstrated that seeds of X. asperula and X. trachyphylla are tolerant to high temperatures caused by fire passage and to drought. These characteristics are important for these species to maintain reproductive success in the harsh environment of campo rupestre . [ABSTRACT FROM AUTHOR]

Xyridaceae comprises the seventh largest monocot family in Brazil, with Xyris L. being the largest and most representative genus there. The most important center of diversity for this genus is the Espinhaço Range in southeastern Brazil, where these plants grow in rocky open fields ( campo rupestre ), usually on humid or boggy soils. The present work examined the seed germination of Xyris species to evaluate the relationships between the germination requirements and their geographic distribution patterns and the distinct micro-habitats they occupy. Laboratory tests were carried out to evaluate light, temperature, and oxygen restriction effects on the germination of eight Xyris species occurring in the Espinhaço Range. All eight species had small seeds that were intolerant of high temperatures (≥35 °C) when imbibed, absolute light requirements for germination, and were able to germinate under hypoxic conditions. The effects of temperature on seed germination do not explain the patterns of geographic distribution nor the endemism seen among the species examined here. Additionally, the occurrence of Xyris species in soils with different water retention capacities cannot be attributed to the capacity of their seeds to germinate under conditions of hypoxia, as the seeds of species that occur on well-drained soils also germinated under low-oxygen condition. [ABSTRACT FROM AUTHOR]

We provide a detailed comparative study of floral ontogeny and vasculature in Xyridaceae, including Xyris, Abolboda and Orectanthe. We evaluate these data in the context of a recent well-resolved phylogenetic analysis of Poales to compare floral structures within the xyrid clade (Xyridaceae and Eriocaulaceae). Xyrids are relatively diverse in both flower structure and anatomy; many species incorporate diverse and unusual floral structures such as staminodes and stylar appendages. Xyridaceae possess three generally epipetalous stamens in a single whorl; the 'missing' stamen whorl is either entirely absent or transformed into staminodes. Fertile stamens each receive a single vascular bundle diverged from the median petal bundle. In Xyris, the stamen bundle diverges at the flower base, but it diverges at upper flower levels in both Abolboda and Orectanthe. In species of Abolboda that possess staminodes, staminode vasculature is closely associated with the lateral vasculature of each petal. Despite the likely sister-group relationship between Eriocaulaceae and Xyridaceae, our character optimization indicates that the stylar appendages that characterize some Xyridaceae (except Xyris and Achlyphila) are non-homologous with those of some Eriocaulaceae. On the other hand, it remains equivocal whether the loss of a fertile outer androecial whorl occurred more than once during the evolutionary history of the xyrid clade; this transition occurred either once followed by a reversal to fertile stamens in Eriocauloideae and staminodes in some Xyridaceae, or twice independently within both Xyridaceae and Eriocaulaceae. [ABSTRACT FROM AUTHOR]

Dormancy cycles are an important mechanism for avoiding seed germination under unfavourable periods for seedling establishment. This mechanism has been scarcely studied in tropical species. Here, we studied three tropical and perennial species of Xyris, X. asperula, X. subsetigera and X. trachyphylla, to investigate in situ longevity and the existence of seasonal seed dormancy cycles., Seeds of three species of Xyris were buried in their natural habitat, with samples exhumed bimonthly for 18 months. Germination of exhumed seeds was assessed under a 12-h photoperiod over a broad range of temperatures. Seeds of X. trachyphylla were also subjected to treatments to overcome secondary dormancy., Seeds of all species are able to form a persistent seed bank and exhibit seasonal changes in germinability. Secondary dormancy was acquired during the rainy summer and was overcome during the subsequent dry season (autumn/winter). Desiccation partially overcomes secondary dormancy in X. trachyphylla seeds., Soil seed bank persistence and synchronisation of seed germination under favourable conditions for seedling establishment contribute to the persistence and regeneration of X. asperula, X. subsetigera and X. trachyphylla in their natural environment. [ABSTRACT FROM AUTHOR]

Premise of research. Orectanthe consists of only two species with a distribution limited to the Guayana Highlands, in locations where sample collection is challenging. The genus belongs to Abolbodoideae, one of the two subfamilies of Xyridaceae. The development of the ovule, fruit, and seed of Orectanthe sceptrum was studied using a comparative approach to provide useful information for the taxonomy and phylogeny of the family. Methodology. Flowers and fruits at different developmental stages were analyzed by light and scanning electron microscopy. Optimization of select characters on a previously published phylogeny was conducted to evaluate the evolution of some embryological characters in Poales. The seed weights of O. sceptrum and species of Abolboda and Xyris were measured for comparison. Pivotal results. Orectanthe sceptrum presents anatropous, tenuinucellate, and bitegmic ovules with a micropyle bounded by both integuments. The multilayered outer integument forms the seed wing, which is a unique feature of this genus. The development of megagametophyte is of the Polygonum type. The seed has a tanniferous hypostase, a starchy endosperm, and a reduced and undifferentiated embryo. The seed coat is composed of a tanniferous tegmen (endotegmen and exotegmen) and testa (endotesta and exotesta). The mechanical layer of the seed coat is the exotesta. The fruit has a sclerenchymatous exocarp. The ancestral character-state reconstructions show that anatropous, crassinucellate ovules, megagametophyte development of the Polygonum type, and nuclear endosperm are the ancestral conditions in Poales. Orthotropous, tenuinucellate ovules appear in the most recent common ancestor of the xyrid, restiid, and graminid clades. The seed weight of O. sceptrum is one to two orders of magnitude greater than the seed weight of Abolboda and Xyris species. Conclusions. Anatropous ovules and a seed coat formed by endotegmen, exotegmen, endotesta, and exotesta link Orectanthe to Abolboda (Abolbodoideae). Such characteristics are not found in Xyris (Xyridoideae), which is consistent with the subfamilial division. The presence of anatropous ovules in Abolbodoideae most likely represents a character reversal. The greater seed weight of O. sceptrum may explain the presence of wings in the seeds. [ABSTRACT FROM AUTHOR]

The effects of fire on the vegetation vary across continents. However, in Neotropical fire-prone grasslands, the relationship between fire and seed germination is still poorly understood, while their regeneration, especially after strong anthropogenic disturbance, is challenging for their conservation. In the present study, we assessed diversity of germination strategies in 15 dominant herbaceous species from Neotropical altitudinal grasslands (locally known as campos rupestres). We exposed seeds to several fire-related treatments. We also compared germination between regularly and post-fire fruiting species. Finally, we investigated the diversity of dormancy classes aiming at better understanding the biogeography and phylogeny of seed dormancy. Germination strategies varied among families. Velloziaceae and Xyridaceae produced non-dormant, fast-germinating seeds. Cyperaceae and Poaceae showed an extremely low or null germination due to a high proportion of unviable or embryo-less seeds. The seeds of campo rupestre grasslands are fire resistant, but there is no evidence that fire triggers germination in this fire-prone ecosystem. Although heat and charred wood did not promote germination, smoke enhanced germination in one grass species and decreased the mean germination time and improved synchrony in Xyridaceae and Velloziaceae. Fire had a positive effect on post-fire regeneration by stimulating fruit set in some Cyperaceae and Poaceae species. These species produced faster germinating seeds with higher germination percentage and synchrony compared to regularly fruiting Cyperaceae and Poaceae species. This strategy of dispersion and regeneration seems to be an alternative to the production of seeds with germination triggered by fire. Physiological dormancy is reported for the first time in several clades of Neotropical plants. Our data help advance the knowledge on the role of fire in the regeneration of Neotropical grasslands. [ABSTRACT FROM AUTHOR]

Premise of research. Xyridaceae includes two subfamilies with a total of five genera. Xyridoideae has only the single genus Xyris, and Abolbodoideae includes the remaining genera. The inter- and intrafamilial relationships among Xyridaceae have not yet been clarified, and this study therefore aimed to investigate the anther wall and pollen grain development in Abolboda and Orectanthe species, searching for characters that can be used in taxonomic and phylogenetic analyses. Methodology. Anthers from flowers at different stages of development were examined using both LM and SEM. Pivotal results. All studied species present the following: monocotyledonous type of anther wall development, single-layered endothecium with band-like thickenings in the mature anther, single ephemeral middle layer, multilayered and plasmodial tapetum, successive microsporogenesis, and spherical inaperturate pollen grains. Characteristics such as reduced type of anther wall development, single-layered and secretory tapetum with uninucleate or binucleate cells, and elliptical sulcate pollen grains with a reticulate exine are present in Xyris and differentiate this genus from Abolboda and Orectanthe. The characteristics reported for Xyris are also present in Mayacaceae, which used to form the xyrid clade of Poales with Eriocaulaceae and Xyridaceae. Abolboda and Orectanthe share with Eriocaulaceae the monocotyledonous type of anther wall development with an ephemeral middle layer, an endothecium with band-like thickenings, and pollen grain exine with projections. The presence of a multilayered tapetum is exclusive to Abolboda and Orectanthe among the Xyridaceae and also among the Poales. Conclusions. The embryological characteristics support the division of Xyridaceae into two subfamilies. In contrast with the megasporogenesis and megagametogenesis, the microsporogenesis and microgametogenesis characteristics were quite variable within the xyrid clade, with successive microsporogenesis being the only characteristic shared by Xyridaceae, Eriocaulaceae, and Mayacaceae. [ABSTRACT FROM AUTHOR]

The development of the ovule, fruit and seed of Xyris spp. was studied to assess the embryological characteristics of potential taxonomic usefulness. All of the studied species have (1) orthotropous, bitegmic and tenuinucellate ovules, with a micropyle formed by both the endostoma and exostoma; (2) a cuticle in the ovules and seeds between the nucellus/endosperm and the inner integument and between the inner and outer integuments; (3) helobial, starchy endosperm; (4) a reduced, campanulate and undifferentiated embryo; (5) a seed coat formed by a tanniferous endotegmen, endotesta with thick-walled cells and exotesta with thin-walled cells; and (6) a micropylar operculum formed from inner and outer integuments. The pericarp is composed of a mesocarp with cells containing starch grains and an endocarp and exocarp formed by cells with U-shaped thickened walls. The studied species differ in the embryo sac development, which can be of the Polygonum or Allium type, and in the pericarp, which can have larger cells in either endocarp or exocarp. The Allium-type embryo sac development was observed only in Xyris spp. within Xyridaceae. Xyris also differs from the other genera of Xyridaceae by the presence of orthotropous ovules and a seed coat formed by endotegmen, endotesta and exotesta, in agreement with the division of the family into Xyridoideae and Abolbodoideae. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177, 619-628. [ABSTRACT FROM AUTHOR]

A taxonomic treatment of the Xyridaceae in the Viruá National Park is presented. Located in Roraima state, northern Brazil, the park comprises a mosaic of lowland vegetation types, including forests, wetlands, and one of the largest continuous areas of campinarana in the Brazilian Amazon Basin. Xyridaceae are represented in the park by 20 species in the genera Abolboda and Xyris. Although the four species of Abolboda are widespread, most of the Xyris species (75%) are endemic to Amazonian open vegetation formations, such as campinaranas and savannas. This study was based on field, herbarium, and scanning electron microscopy research. The taxonomic treatment includes identification keys to the genera and species, morphological descriptions, SEM images of seeds for Xyris species, iconography, geographic distribution and comments on the ecology of the species. The poorly known Xyris connosepala is synonymized in Xyris guianensis. [ABSTRACT FROM AUTHOR]

Poales represents a major part of Angiosperm and Monocot diversity. The families encompass ca. 20,000 species which is about 7% of the Angiosperms and 33% of the Monocots. Bromeliaceae, Cyperaceae, Eriocaulaceae, Juncaceae, Mayacaceae, Poaceae, Rapateaceae, Thurniaceae, Typhaceae, and Xyridaceae are the families represented in the Neotropics. In general terms some areas in the Neotropics could be considered hotspots for Poales with a high number of species in several genera and several centers of endemism - the Guayana Shield, Espinhaço Range and Atlantic Forest are highly diverse in Poales. In terms of the Brazilian flora, the order is well represented in the entire country with almost 4,400 species. It represents more than 50% of the total number of species of Monocotyledons in Brazil. The main goal here is to summarize the available information and provide an overview of the Poales in the Neotropics. The state of knowledge for each family, focused on the Brazilian flora, is provided and reinforces the importance of new studies in key-groups. [ABSTRACT FROM AUTHOR]

Cercosporoid fungi (formerly Cercospora s. lat.) represent one of the largest groups of hyphomycetes belonging to the Mycosphaerellaceae (Ascomycota). They include asexual morphs, asexual holomorphs, or species with mycosphaerella-like sexual morphs. Most of them are leaf-spotting plant pathogens with special phytopathological relevance. In the first part of a new monographic work, cercosporoid hyphomycetes occurring on other fungi (fungicolous species), on ferns (pteridophytes) and gymnosperms were treated. This second part deals with cercosporoid fungi on monocots (Liliopsida; Equisetopsida, Magnoliidae, Lilianae), which covers species occurring on host plants belonging to families arranged in alphabetical order from Acoraceae to Xyridaceae, excluding Poaceae (cereals and grasses) which requires a separate treatment. The species are described and illustrated in alphabetical order under the particular cercosporoid genera, supplemented by keys to the species concerned. A detailed introduction, a survey of currently recognised cercosporoid genera, a key to the genera concerned, and a discussion of taxonomically relevant characters were published in the first part of this series. Neopseudocercospora, an additional recently introduced cercosporoid genus, is briefly discussed. The following taxonomic novelties are introduced: Cercospora alpiniigena sp. nov., C. neomaricae sp. nov., Corynespora palmicola comb. nov., Exosporium miyakei comb. nov., E. petersii comb. nov., Neopseudocercospora zambiensis comb. nov., Passalora caladiicola comb. nov., P. streptopi comb. nov., P. togashiana comb. nov., P. tranzschelii var. chinensis var. nov., Pseudocercospora beaucarneae comb. nov., P. constrictoflexuosa comb. et stat. nov., P. curcumicola sp. nov., P. dispori comb. nov., P. smilacicola sp. nov., P. urariigena nom. nov., Zasmidium agavicola comb. nov., Z. cercestidis-afzelii comb. nov., Z. citri-griseum comb. nov., Z. cyrtopodii comb. nov., Z. gahnae comb. nov., Z. indicum comb. nov., Z. liriopes comb. nov., Z. mycovellosielloides sp. nov., Z. scleriae comb. nov., Z. smilacicola comb. nov., and Z. thaliae comb. nov. Article info: Submitted: 2 June 2014; Accepted: 31 October 2014; Published: [ABSTRACT FROM AUTHOR]

La familia Xyridaceae es reconocida en el Perú por presentar un género, Xyris, y once especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004), todas hierbas. En este trabajo reconocemos un endemismo. Este taxón ha sido encontrado en los pajonales de la región Páramo, a 3300 m de altitud. No se encuentra representada dentro de áreas naturales protegidas.

"Sempre-vivas" é o nome dado no Brasil a partes de plantas, geralmente escapos e inflorescências, que conservam a aparência de estruturas vivas mesmo depois de destacadas e secas e que são comercializadas e exportadas para decoração de interiores. Folhas, frutos e sementes também são utilizados, mas em menor escala. As espécies de "sempre-vivas" são oriundas dos cerrados do Centro-Oeste e Sudeste do Brasil e, as de maior valor comercial, dos campos rupestres de Minas Gerais, Bahia e Goiás. Entre estas, predominam espécies de Eriocaulaceae, Poaceae (Gramineae), Xyridaceae, Cyperaceae e Rapateaceae, em ordem decrescente de importância. O maior centro de comercialização é a cidade de Diamantina, em Minas Gerais, com 25 espécies de Eriocaulaceae, 12 de Poaceae, 9 de Xyridaceae, 2 de Cyperaceae e 1 de Rapateaceae. São apresentadas chaves para identificação dos gêneros, baseadas em caracteres do material comercializado, além de breves descrições, ilustrações, listagem de material analisado, nomes populares e comentários sobre as espécies."Sempre-vivas" is the name given in Brazil to parts of plants, usually scapes and inflorescences, that conserve the appearance of the living structures even after dryed out (everlasting). They are sold locally and exported for interior decoration. In a smaller scale, leaves, fruits and seeds are also used. "Sempre-vivas" species are gathered in the savanna-like formations ("cerrados") of the Central-West and Southeast regions of Brazil, while species of greater commercial value originate from the grasslands with rocky outcrops ("campos rupestres") from the States of Minas Gerais, Bahia and Goiás. Species of Eriocaulaceae, Poaceae (Gramineae), Xyridaceae, Cyperaceae and Rapateaceae predominate in a decreasing order. The largest commercial center for this material is the city of Diamantina, in the State of Minas Gerais, where 25 species of Eriocaulaceae, 12 of Poaceae, 9 of Xyridaceae, 2 of Cyperaceae and 1 of Rapateaceae are commercialized. Identification keys for the genera based on characters found in the commercialized parts, brief descriptions, illustrations, list of the analysed material, popular names and comments on the species are presented.

São propostas alterações nomenclaturais e taxonômicas em Xyris, status novum e dois novos sinônimos.Nomenclatural and taxonomic changes are proposed in Xyris; one new status and two new synonym.

As folhas de X. anamariae, X. archeri, X. hymenachne, X. melanopoda, X. minarum, X. obcordata, X. paraensis, X. pilosa, X. platystachia, X. pterygoblephara, X. savanensis, X. spinulosa, X. tortilis e X. tortula, foram preparadas segundo técnicas usuais para estudos anatômicos. A análise comparativa, da região basal desses órgãos, mostrou diferenças na estrutura da epiderme, na organização do mesofilo e no número e grau de agrupamento dos feixes vasculares, dependendo da espécie considerada. Esses aspectos foram utilizados na caracterização de cada representante estudado e, analisados em conjunto para indicar formas diferentes de especialização foliar, relacionadas à deficiência hídrica.The leaves ofX. anamariae, X. archeri, X. hymenachne, X. melanopoda, X. minarum, X. obcordata, X. paraensis, X. pilosa, X. platystachia, X. pterygoblephara, X. savanensis, X. spinulosa, X. tortilis e X. tortula were prepared with the usual methods for anatomical studies. The comparative analysis of the blade base showed differences in the epidermis structure, in the mesophill organization and in the vascular bundles number and fusion, according to the species. These features were used to characterize each species and when combined they may be used to demonstrate leaf specialization forms, related to hydric deficiency.

Xyridaceae belongs to the xyrid clade of Poales, but the phylogenetic position of the xyrid families is only weakly supported. Xyridaceae is divided into two subfamilies and five genera, the relationships of which remain unclear. The development of the ovule, fruit and seed of Abolboda spp. was studied to identify characteristics of taxonomic and phylogenetic value. All of the studied species share anatropous, tenuinucellate and bitegmic ovules with a micropyle formed by the inner and outer integuments, megagametophyte development of the Polygonum type, seeds with a tanniferous hypostase, a helobial and starchy endosperm and an undifferentiated embryo, seed coat derived from both integuments with a tanniferous tegmen and a micropylar operculum, and fruits with a parenchymatous endocarp and mesocarp and a sclerenchymatous exocarp. Most of the ovule and seed characteristics described for Abolboda are also present in Xyris and may represent a pattern for the family. Abolboda is distinguished by the ovule type, endosperm formation and the number of layers in the seed coat, in agreement with its classification in Abolbodoideae. The following characteristics link Xyridaceae to Eriocaulaceae and Mayacaceae, supporting the xyrid clade: tenuinucellate, bitegmic ovules; seeds with a tanniferous hypostase, a starchy endosperm and an undifferentiated embryo; and a seed coat with a tanniferous tegmen. A micropylar operculum in the seeds of Abolboda is described for the first time here and may represent a synapomorphy for the xyrids. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175, 144-154. [ABSTRACT FROM AUTHOR]

Abstract. As part of the results of an inventory of Xyridaceae species from the Rio Preto State Park, Minas Gerais, Brazil, three species of Xyris are proposed as new to science. Xyris nigra, with its blackish and globose spikes, X. scoparia, with linear leaf blades and densely caespitose habit, and X. velutina, with margins of the leaf blades conspicuously villous, are here described and illustrated. For each species, comments are provided on ecology, phenology, and conservation status, in addition to comparisons with morphologically similar species. [ABSTRACT FROM AUTHOR]

Four new species of Xyris (Xyridaceae), X. bituberosa, X. buengkanensis, X. emarginata, and X. thailandica from North-Eastern Thailand are described and illustrated. A provisional conservation assessment for each species is given. [ABSTRACT FROM AUTHOR]

Xyridaceae, Eriocaulaceae, and Mayacaceae form the xyrid clade, which is weakly supported in Poales. The floral anatomy of xyrid species was studied, to contribute to the understanding of the relationships within the group. Both Eriocaulaceae and Xyridaceae have petals with elongated epidermal cells with straight walls, epipetalous stamens, staminodes, anthers with longitudinal dehiscence, an endothecium with band-like thickenings, and a style vascularized by the dorsal carpellary bundles; these characteristics thus corroborate the close relationship of these groups indicated by phylogenetic analyses. Mayacaceae is distinguished by the presence of papillose epidermal cells in the petals, a reduced inner whorl of stamens, poricidal anthers, an endothecium lacking thickenings, a style and stigma vascularized by the dorsal and ventral carpellary bundles, and the presence of an obturator in the ovary wall. A reduction in the inner whorl of fertile stamens also occurs in Juncaceae and Cyperaceae, linking Mayacaceae to the cyperids. The stylar appendages of Orectanthe (Xyridaceae) have been shown to be nectariferous and anatomically similar to those of Abolboda, differentiating these two genera from Xyris (Xyridoideae) and confirming their placement in Abolbodoideae. Stylar appendages also occur in Eriocaulaceae, with the same function, position, and vascularization, and are therefore homologous structures, reinforcing the phylogenetic proximity between Eriocaulaceae and Xyridaceae. [ABSTRACT FROM AUTHOR]