New Entities of Paspalum and a Synopsis of the Dilatata Group

Abstract New entities in the allopolyploid Dilatata complex of Paspalum are formally described and illustrated. Three sexual tetraploids formerly subsumed under Paspalum dilatatum are recognized as discrete taxonomic entities: P. plurinerve and P. vacarianum are described as new species, and P. dilatatum subsp. flavescens is upgraded to species rank as P. flavescens. Both P. vacarianum and P. plurinerve are distributed in the Brazilian southern Plateau (Planalto Meridional), in the states of Rio Grande do Sul and Santa Catarina, the first one in the eastern region and the second one in the western region including adjacent areas of NE Argentina. Paspalum flavescens is distributed in southeastern Uruguay and the provinces of Buenos Aires and Córdoba (Argentina). The apomictic allohexaploid P. torrense, distributed along the coastal areas of the Brazilian states of Rio Grande do Sul, Santa Catarina, and Paraná, and adjacent regions along the edge of the southern Plateau, also deserves specific status, whereas two further hexaploid biotypes are differentiated from the pentaploid P. dilatatum var. dilatatum and described as Paspalum dilatatum var. chiru and P. dilatatum var. uruguaianense. Paspalum dilatatum var. chiru is restricted to a small area around the locality of Molles Grande, in the department of Paysandú, Uruguay; whereas P. dilatatum var. uruguaianense is distributed in the SW of Rio Grande do Sul, Brazil, and northern Uruguay. The Dilatata group of Paspalum is thus comprised of 8 species and 3 varieties, which are summarized here and for which an identification key is provided.

[1]  P. Speranza,et al.  Distribution of genetic and phenotypic diversity in the autogamous perennial Paspalum dilatatum subsp. flavescens Roseng., Arrill. & Izag. (Poaceae) , 2019, Genetic Resources and Crop Evolution.

[2]  R. Vašut,et al.  How apomictic taxa are treated in current taxonomy: A review , 2017 .

[3]  J. Valls,et al.  Paspalum chilense (Poaceae, Paspaleae): A new species from southern South America , 2015 .

[4]  Ben Scott,et al.  Supporting Red List threat assessments with GeoCAT: geospatial conservation assessment tool , 2011, ZooKeys.

[5]  Mónica Arakaki,et al.  A phylogenetic analysis of the genus Paspalum (Poaceae) based on cpDNA and morphology , 2010, Plant Systematics and Evolution.

[6]  P. Speranza.  Evolutionary patterns in the Dilatata group (Paspalum, Poaceae) , 2009, Plant Systematics and Evolution.

[7]  D. Hojsgaard,et al.  Chromosome numbers and ploidy levels of Paspalum species from subtropical South America (Poaceae) , 2009, Genetic Resources and Crop Evolution.

[8]  J. F. Valls,et al.  Cytogenetic analyses in Paspalum L. reveal new diploid species and accessions , 2008 .

[9]  G. Folle,et al.  Nuclear DNA content in allopolyploid species and synthetic hybrids in the grass genus Paspalum , 2007, Plant Systematics and Evolution.

[10]  P. Balatti,et al.  Genetic variability in natural populations of Paspalum dilatatum Poir. analyzed by means of morphological traits and molecular markers , 2007, Genetic Resources and Crop Evolution.

[11]  Neil A. Harriman.  Revisión de las Especies de Paspalum para América del Sur Austral (Argentina, Bolivia, sur del Brasil, Chile, Paraguay, y Uruguay) , 2005 .

[12]  F. Espinoza,et al.  2n+n Hybridization of Apomictic Paspalum dilatatum with Diploid Paspalum Species , 2000, International Journal of Plant Sciences.

[13]  J. Kirschner,et al.  Modes of speciation and evolution of the sections inTaraxacum , 1996, Folia Geobotanica.

[14]  B. Burson.  Genome Relationship and Reproductive Behavior of Intraspecific Paspalum dilatatum Hybrids: Yellow-Anthered x Uruguaiana , 1995, International Journal of Plant Sciences.

[15]  I. Caponio,et al.  Cytogenetics and Reproduction of Paspalum dasypleurum and Its Hybrids with P. urvillei and P. dilatatum Ssp. Flavescens , 1995, International Journal of Plant Sciences.

[16]  I. Caponio,et al.  Cytology and Reproduction of Paspalum densum and Its Genomic Relationship with P. intermedium and P. urvillei , 1993 .

[17]  B. Burson.  Cytology and reproductive behavior of hybrids between Paspalum urvillei and two hexaploid P. dilatatum biotypes. , 1992 .

[18]  B. Burson.  Homology of chromosomes of the X genomes in common and Uruguayan dallisgrass, Paspalum dilatatum , 1991 .

[19]  B. Burson.  Genome Relationships between Tetraploid and Hexaploid Biotypes of Dallisgrass, Paspalum dilatatum , 1991, Botanical Gazette.

[20]  G. W. Evers,et al.  Cytology, Reproductive Behavior, and Forage Potential of Hexaploid Dallisgrass Biotypes , 1991 .

[21]  G. Norrmann,et al.  Interspecific Hybrids between Five Paspalum Species , 1990, Botanical Gazette.

[22]  B. Burson.  Cytogenetics of Paspalum urvillei ✕ P. intermedium and P. dilatatum ✕ P. paniculatum Hybrids 1 , 1979 .

[23]  B. Burson.  GENOME RELATIONS BETWEEN PASPALUM CONSPERSUM AND TWO DIPLOID PASPALUM SPECIES , 1978 .

[24]  F. Salzano,et al.  CYTOGENETIC, ECOLOGIC AND MORPHOLOGIC STUDIES IN BRAZILIAN FORMS OF PASPALUM DILATATUM , 1968 .

[25]  E. C. Holt,et al.  Megasporogenesis, Embryo Sac Development and Embryogenesis in Dallisgrass, Paspalum Dilatatum, Poir1 , 1958 .

[26]  H. Hayward.  Gramineae , 1934, Botanical Gazette.

[27]  M. Guerra,et al.  Effects of the diploidisation process upon the 5S and 35S rDNA sequences in the allopolyploid species of the Dilatata group of Paspalum (Poaceae, Paniceae) , 2019, Australian Journal of Botany.

[28]  Noel H. Holmgren,et al.  Index Herbariorum: A global directory of public herbaria and associated staff , 1998 .

[29]  S. Tt,et al.  Variability in seed production and germination in paspalum-dilatata group (gramineae) , 1995 .

[30]  I. Caponio,et al.  Intra- and interspecific hybridization between dallisgrass and vaseygrass. , 1990 .

[31]  E. Kellogg.  Variation and species limits in agamospermous grasses. , 1990 .

[32]  J. Smith,et al.  Proceedings Of The Xiv International Grassland Congress , 1983 .

[33]  B. Burson,et al.  Cytogenetics of Paspalum urvillei ✕ P. juergensii and P. urvillei × P. vaginatum Hybrids 1 , 1972 .

[34]  A. Chase.  The North American species of Paspalum , 1929 .