Karyotype analysis in Brachiaria (Poaceae) species

This is the first karyotype characterization of Brachiaria species. Twelve accessions belonging to five species were analysed. The basic chromosome number was x = 9 and 7, the same reported for the tribe Paniceae. Variations in the chromosome number were observed in B. decumbens (2n = 18; 36) and B. humidicola (2n = 36; 42; 54). Chromosome numbers of 2n = 18 in B. ruziziensis and 2n = 36 in B. brizantha and B. jubata were recorded. Inter- and intraspecific karyotype differentiation of the accessions analysed was facilitated by variations in karyotypic symmetry. The karyotypes were generally considered symmetrical, with a tendency to asymmetry in the direction of the polyploids. It is suggested that addition, deletions and mainly polyploidy have been the most direct causes involved in the chromosome evolution of this genus.     

A new cleistogamous South American species of Eragrostis (Poaceae: Chloridoideae)

Eragrostis riobrancensis (Poaceae, Chloridoideae), a new species with cleistogamous spikelets from sandy river banks of southern Guyana and adjacent Terr. Roraima, Brazil, is described and illustrated.     

披碱草属(Elymus L.)两个物种之订正

披碱草属Elymus L．是小麦族Triticeae Dumort．中最大的属,全世界共有150多个种,广泛分布于 温带地区。我国约有80余种(包括鹅观草属Roegneria C．Koch),是披碱草属的重要分布区和多样性分 化中心。由于披碱草属植物种类繁多、分布广泛、生境多样以及形态变异较为复杂,导致该属在分类上 存在许多问题。同时,由于地域的局限和地区间交流的缺乏,致使同一种披碱草属植物被不同的学者多 次发表及同物异名现象的出现。本文对E．antiquus和E．burchan-buddae这两个曾多次被订名的披碱草 属物种进行了分类订正。     

A new species of Sporobolus (Poaceae) from southeastern India

A new species of Sporobolus, S. hajrae , from coastal Tamil Nadu in southern India is described and illustrated.     

八个四倍体鹅观草属物种的核型研究

对8个鹅观草属物种的核型进行了研究。核型公式如下:纤穗鹅观草2n=4x=28=20m+8sm(2sat);紫穗鹅观草2n=4x=28=22m(2sat)+6sm;假花鳞草2n=4x=28=24m(2sat)+4sm;肃草2n=4x=28=22m+6sm(2sat);小颖鹅观草2n=4x=28=22m+6sm(2sat);纤瘦鹅观草2n=4x=28=24m(4sat)+4sm;变颖鹅观草2n=4x=28=20m+8sm(2sat);毛花鹅观草2n=4x=28=24m(2sat)+4sm。它们的核型属1A或2A型。其中后5个物种的核型为首次报道。     

A new species of rhytachne (Poaceae: Andropogoneae) from northern South America

Rhytachne gonzalezii is described and illustrated. It ranges from Apure, Venezuela to Pará, Brazil. It is the third annual species known in this tropical African-American genus. Previously it had been confounded with the perennialR. rottboellioides from which it differs in its habit, branching culms, smaller sessile spikelets and rachis internodes, and awned upper glume.     

A new multiflorous species of Leymus (Poaceae: Triticeae) from western China

A new species of Leymus section Racemosus, L. pluriflorus L.B.Cai & T.L.Zhang, is described and illustrated. It grows in the eastern part of Qinghai Province and the southern part of Gansu Province, China. It most closely resembles L. crassiusculus L.B.Cai, from which it differs in having longer rachis internodes, some pedicellate spikelets, more florets per spikelet, glabrous lemmas, shorter paleas and shorter anthers. It differs from all other Chinese species taxa in Leymus with regard to the large number (8–12) of florets in its spikelets, and from all species of Leymus in adjacent countries in having three to four spikelets per node. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 343–348.     

A new rhizomatous Oryza species (Poaceae) from Sri Lanka

VAUGHAN, D. A., 1990. A new rhizomatous Oryza species (Poaceae) from Sri Lanka. The confusing taxonomy of the Sri Lankan Oryza officinalis complex is clarified with the recognition of a new rhizomatous species, Oryza rhizomatis Vaughan. This species has been found across the dry zone. The other species of the complex in Sri Lanka, O. eichingeri , occurs in moist habitats and is smaller and less common than 0. rhizomatis. The new species is described.     

10个四倍体披碱草属物种的核型（简报）

本文报道了来自北美和亚洲10个四倍体披碱草属物种Elymus(StStHH)的核型.其核型属于1A或2A型,核型公式如下:24m+4sm(2sat)(加拿大披碱草E. canadensis);20m+8sm(4sat)(E. elymoides);20m+8sm(4sat)(E. glaucus);22m+6sm(4sat)(E.lanceolatus);22m+6sm(2sat)(E. mutabilis);22m+6sm(2sat)(老芒麦.E.sibiricus);24m+4sm(E.trachycaulus);22m+4sm+2st(2sat)(E.trachycaulus ssp.subsecundus);24m+4sm(4sat)(E.virginicus);20m+8sm(4sat)(E.wawawaiensis).     

Relationships between seven species ofVulpia (Poaceae)

Seven species ofVulpia were subjected to morphological and protein studies using principal component and cluster analysis and theJaccard's Similarity Coefficient. Studies showed all species were uniform and distinct from each other. Species of sect.Loretia were very dissimilar from those of sect.Monachne and sect.Vulpia. The latter section comprises taxa of high mutual affinity.     

New species of cryptochloa and piresia (Poaceae: Bambusoideae)

Two new species are added toCryptochloa,C. unispiculata from Peru andC. capillata from Brazil, the latter transferred from the genusOlyra. The genusPiresia is also augmented by two new species,P. macrophylla from Peru andP. leptophylla from Bahia, Brazil. These species represent, respectively, the westernmost and easternmost limits of distribution of the genus.     

C-banding analysis of eight species ofKengyilia (Poaceae: Triticeae)

To characterize chromosomes and the interspecific relationships within the genus Kengyilia, 8 species were used for Giemsa C-banding analysis. Results indicated that the species differed in C-banding patterns. K. gobicola, K. alatavica and K. batalinii had distinct centromeric bands and no banded chromosomes, while K. hirsuta, K. longiglumis, K. melanthera, K. rigidula and K. thoroldiana had more abundant and diagnostic C-bands with interstitial and terminal bands.     

Relationships between five species ofLolium (Poaceae)

Morphological analysis and electrophoresis of seed proteins of fiveLolium species disclosed that they form two distinct groups corresponding to those recognized from compatibility data.Lolium temulentum andL. remotum of the self-pollinated group were shown to be distinct but closely related species. Morphological intergradation and high similarities between protein profiles ofL. perenne, L. multiflorum andL. rigidum (cross-pollinated species) suggest little genetic differentiation between these taxa. This implies that treatment at the infraspecific level might better accomodate the data.     

Characterization of microsatellite loci in Spartina species (Poaceae)

The cordgrasses in the genus Spartina have become model organisms for studying biological invasions from both ecological and genetic perspectives. Here we characterize 11 disomic loci in Spartina alterniflora that show promise for population studies and for studying hybridization events between S. alterniflora and S. foliosa. Comparisons among invasive and native S. alterniflora populations showed that levels of allelic variation are lower in invasive populations. In addition, nearly all loci that amplified in S. foliosa populations and in a swarm of S. alterniflora×foliosa hybrids were polymorphic. We also found that several loci amplified successfully in other Spartina species.     

Aulonemia yanachagensis (Poaceae: Bambusoideae: Bambuseae): A new species from central Peru

Aulonemia yanachagensis is described from cloud forests at 2600–3000 m elevation in the Parque Nacional Yanachaga-Chemillén Prov. Oxapampa, Dept. Pasco, Peru. It differs from all other congeners in its combination of prominent sheath auricles, with abundant radiate fimbriae, small foliage leaf blades, and awnless spikelets.     

Megasporogenesis and megagametogenesis in several Tripsacum species (Poaceae)

The Tripsacum agamic complex (x = 18) will provide valuable characters for maize breeding, provided that apomixis can be manipulated. Apomixis in Tripsacum was first reported 40 years ago, but its prevalence in the genus has not been established. Reproductive development was determined for eight Mexican and two South American Tripsacum species by microscopic analysis of ovaries cleared in a benzyl benzoate-dibutyl phthalate solution using interference contrast optics. The occurrence and distribution of callose deposition during megasporogenesis were determined by fluorescence microscopy of ovaries optically cleared in an aqueous sucrose solution containing aniline blue. Diploid genotypes were sexual. Polyploid forms reproduced apomictically following the Antennaria type (complete meiosis abortion) of diplospory. The Taraxacum type (unreduced megaspore production through meiotic restitution nuclei) of diplospory also occurred but rarely. The walls of diplosporic megasporocytes lacked callose whereas the walls of sexual megasporocytes contained a normal complement of callose. The absence of callose suggests that the diplosporic forms of reproduction result from mutations affecting the normal meiotic process. Apomixis in the Tripsacum genus is facultative, and the production of new polyploid genotypes through genetic exchanges involving both apomictic and sexual genotypes is possible.     

The species of Chusquea (Poaceae: Bambusoideae) with verticillate buds

A natural alliance of four species ofChusquea is characterized by having verticillate branches and a spikelet in which the transitional glumes one and two are very small or scalelike, and transitional glumes three and four are about equal to each other and about one-half or three-quarters as long as the lemma. Two of the four species,C. circinata andC. coronalis, are described as new and are provided with illustrations. The other two species,C. liebmannii Fourn. andC. pittieri Hack., are included in a key. The types and other collections are cited for the four species and their relationships are discussed.     

Three new species ofTrisetum (Poaceae) from China

Three new species of the genusTrisetum from the province Yunnan are described:Trisetum lautum, T. debile andT. yunnanense which belong toTrisetum flavescens-group.     

RAPD Study on Inter species Relationships in Roegneria (Poaceae: Triticeae)

To assess the relationships among 26 species in Roegneria C. Koch, 34 random decamer primers were screened for RAPD fragments. 28 primers produced polymorphic RAPD products. Data from 16 primers were used for RAPD assay. By NTSYS-pc program, Jaccard' s genetic similarity coefficients were generated and dendrogram was constructed using UPGMA. It is concluded as follows: (1) Distinct genetic differences and extensive genetic diversity were present among the species. (2) There were some genetic differences between StY and StYH genomes, and StY and StYH had a certain degree of differentiations respectively which were related to geographic regions, the farther the geographic distribution between species, the less the similarity to each other. (3) When different accessions in a species, such as species with similar morphological characters, homologous genomes and similar geographic distribution, were clustered together respectively, it suggusted that they had closer relationships. (4) The awnless species R. alashanica Keng and R. magnicaespes (D. F. Cui) L. B. Cai, in Roegneria, were separated from the other species analysed in this study, indicating that these two species had intensive genetic differences from the others. (5) R. caucasica C. Koch, a species from Western Asia, was quite different from the other species contained StY genomes in Roegneria from Eastern Asia and Central Asia. (6) The results were in consistance with that of the analysis of morphology and chromosome pairing in the taxonomic treatments for R. ciliaris (Trin) Nevski and R. japonensis (Honda) Keng, R. tenuispica J. L. Yang et Y. H. Zhou and R. pendulina Nevski, and R. tsukushiensis (Honda) Ohwi and R. kamoji Ohwi. The present study discussed the usefulness of RAPD markers in the systematic study of Roegneria.