Based on morphological and molecular evidence we transfer the species of Trisetum sect. Trisetaer... more Based on morphological and molecular evidence we transfer the species of Trisetum sect. Trisetaera, T. hispidum, and Trisetokoeleria taymirica into Koeleria, describe Koeleria sect. Hispanica, and provide a new generic emendation. A total of 49 new combinations or new names are included. Additionally, we lectotypify Avena clarkei Hook f., Avena micans Hook. f., Avena subalpestris Hartm., Avena subspicata var. agrostidea Laest., Trisetum pubiflorum Hack., Trisetum spicatum f. minor Kom., and Trisetum spicatum f. umbrosum Kom. RESUMEN De acuerdo con diversas pruebas de carácter morfológico y molecular, transferimos las especies de Trisetum sect. Trisetaera, T. hispidum y Trisetokoeleria taymirica a Koeleria, describimos Koeleria sect. Hispanica y enmendamos la descripción de este género. Presentamos un total de 49 combinaciones o nombres nuevos. Además, designamos lectotipos para Avena clarkei Hook f., Avena micans Hook. f., Avena subalpestris Hartm., Avena subspicata var. agrostidea Laest., Trisetum pubiflorum Hack., Trisetum spicatum f. minor Kom. y Trisetum spicatum f. umbrosum Kom. Recently there has been considerable progress in the systematics of Trisetum Pers. [Poeae: Pooideae: Poaceae; type T. flavescens (L.) P. Beauv.], a group of perennials with a complicated taxonomic history due to the variability and overlapping morphologies of its species and infrageneric taxa (Randall & Hilu 1986; Finot 2010). Recent molecular phylogenetic studies indicate that
Based on morphological and molecular evidence we present new combinations or new names for 77 tax... more Based on morphological and molecular evidence we present new combinations or new names for 77 taxa of Cinnagrostis, seven taxa of Deschampsia, and 24 taxa of Peyritschia; and describe three new genera, Greeneochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Echinopogoninae), Paramochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Calothecinae), and Laegaardia P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Calothecinae) with two, two and one species, respectively. In addition to the 116 new taxonomic entities, we provide a key to the genera of American grasses presently or formerly treated in Calamagrostis or Deyeuxia and generic emendations for Cinnagrostis and Peyritschia. RESUMEN De acuerdo con evidencias de carácter morfológico y molecular se presentan nuevas combinaciones o nuevos nombres para 77 táxones de Cinnagrostis, siete táxones de Deschampsia y 24 táxones de Peyritschia, así como la descripción de tres nuevos géneros, Greeneochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribu Echinopogoninae), Paramochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribu Calothecinae) y Laegaardia P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribu Calothecinae) con dos, dos y una especie respectivamente. Además de las 116 nuevas entidades taxonómicas, proporcionamos una clave para los géneros de gramíneas americanas tratadas actual o anteriormente en Calamagrostis o Deyeuxia y enmendamos los genéros Cinnagrostis y Peyritschia. In a large unpublished molecular DNA sequence study using four gene regions (ITS, rpl32-trnL spacer, rps16-trnK spacer, and rps16 intron) we found most South American species of Deyeuxia Clarion ex P. Beauv. and Calamagrostis Adans., to align in a large clade excluding the type species of each of these genera (Peterson et al., in prep.). These results were largely corroborated by Saarela et al, (2010, 2017) in the study of Poeae R. Br. chloroplast group I where genera were split into Koeleriinae Asch. & Graebn. clade A (e.g. Koeleria Pers. and others) and Koeleriinae clade B (Cinnagrostis Griseb., Peyritschia E. Fourn., and others). We, therefore are resurrecting Cinnagrostis (Grisebach, 1874), a little known genus described from a single dichogamous species, C. polygama Peterson et al.: New grass combinations and names styles 2, stigmas feathery; lodicules 2, membranous, generally with 2 unequal lobes, glabrous or sometimes ciliate. Caryopses usually fusiform to oblong, sometimes laterally compressed, pericarp adherent, endosperm dry, pasty, or liquid. Basic chromosome number x = 7.
Based on morphological and molecular evidence we present new combinations or new names for 77 tax... more Based on morphological and molecular evidence we present new combinations or new names for 77 taxa of Cinnagrostis, seven taxa of Deschampsia, and 24 taxa of Peyritschia; and describe three new genera, Greeneochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Echinopogoninae), Paramochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Calothecinae), and Laegaardia P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Calothecinae) with two, two and one species, respectively. In addition to the 116 new taxonomic entities, we provide a key to the genera of American grasses presently or formerly treated in Calamagrostis or Deyeuxia and generic emendations for Cinnagrostis and Peyritschia.
The original version of this Article contained an error in the title of the paper, where the word... more The original version of this Article contained an error in the title of the paper, where the word "polyploidization" was incorrectly given as "polypoidization". This has now been corrected in the PDF and HTML versions of the Article.
native to China. Mature, dry caryopses were examined with a low-power stereo microscope and the m... more native to China. Mature, dry caryopses were examined with a low-power stereo microscope and the most important characters were described for each species. When available, more than one accession was examined to study the variation, and additional accessions were drawn for certain species to show the variation. Consequently, the description and illustration for each species were derived from one to several accessions. The caryopses were drawn in four aspects: ventral, lateral, and dorsal views; and transverse section. Scanning electron microscopy (SEM) was conducted by direct mounting of the dry caryopsis on an aluminum stub and coating with gold palladium. Samples were then examined using SEM and photographed. The working classification adopted for the purpose of study arranges the genera according to genome (Table 1) starting with Elymus and includes the sometimes segregated genera Elytrigia, Leymus, and Psathyrostachys. Elymus is employed in a rather restricted sense and Aegilops and Triticum are treated as distinct. Sitanion and Hystri.x are tentatively included in Elymus because they share the same genome (Dewey, 1984:246-250; Love, 1982, 1984:447). Henrardia is included in the tribe in agreement with Hubbard (1946) and recent literature. Brachypodium is added to this study because Clayton and Renvoize (1986) included the genus in their treatment of the Triticeae and Macfarlane and Watson (1982) and Kellogg (1989) have recognized the genus as a sister group to the tribe. Acknowledgments.-We dedicate this paper to Regina O. Hughes in recognition of her long and distinguished career as a botanical artist, as well as for her accurate and artistic drawings that are presented here. Financial support during early parts of the study was provided by the
Evidence for global warming is inferred from spring advances in first-flowering in plants. The tr... more Evidence for global warming is inferred from spring advances in first-flowering in plants. The trend of average first-flowering times per year for the study group shows a significant advance of 2.4 days over a 30-year period. When 11 species that exhibit later first-flowering times are excluded from the data set, the remaining 89 show a significant advance of 4.5 days. Significant trends for earlier-flowering species range from •3.2 to •46 days, while those for later-flowering species range from-1-3.1 to-1-10.4 days. Advances of first-flowering in these 89 species are directly correlated with local increase in minimum temperature (Tf^in).
A new combination, Guadua chacoen¬ sis, is made. Based on morphological evidence, G. chacoensis a... more A new combination, Guadua chacoen¬ sis, is made. Based on morphological evidence, G. chacoensis appears closely allied to G. trinii. A detailed illustration of the species is included, and morphological descriptions and illustrations of the seedling and fruit are provided.
This paper provides several nomenclatural modifications based on a recent molecular study of Lept... more This paper provides several nomenclatural modifications based on a recent molecular study of Leptochloa. One generic transfer and four new varietal combinations are proposed for Dinebra Jacq. One orthographic correction and three new varietal combinations are provided in Diplachne P. Beauv. Two corrections are made for the specific epithets of Disakisperma. One orthographic correction is provided for Leptochloa.
Muhlenbergiinae are a subtribe in the grass (Poaceae) subfamily Chloridoideae, tribe Cynodonteae.... more Muhlenbergiinae are a subtribe in the grass (Poaceae) subfamily Chloridoideae, tribe Cynodonteae. The morphologically diverse group includes 10 genera and ca. 174 species and is restricted almost entirely to the New World, with a center of diversity in Mexico (125 species). With ca. 153 species, Muhlenbergia is by far the largest genus, and is divided into two subgenera, Muhlenbergia and Trichochloa, the latter with two sections. The other, much smaller genera are Aegopogon (4 species), Bealia (1), Blepharoneuron (2), Chaboissaea (4), Lycurus (3), Pereilema (4), Redfieldia (1), Schaffnerella (1), and Schedonnardus (1). We conducted a phylogenetic study of Muhlenbergiinae based on parsimony analysis of DNA sequences of the nuclear ribosomal internal transcribed spacer region (ITS1 + 5.8S + ITS2) and chloroplast trnL intron, trnL 3' exon, and trnL-trnF intergenic spacer. All genera were sampled, including 52 species of Muhlenbergia representing both subgenera and sections. Muhlenbergia and Pereilema are not monophyletic in the resulting trees. The species of Pereilema and the other small genera are nested within Muhlenbergia in three main lineages. One of the lineages includes a monophyletic Muhlenbergia subgen. Trichochloa. Another lineage comprises species having leaf anatomy predictive of the PCK subtype of C 4 photosynthesis. Based on the results of this study, we favor expanding the circumscription of Muhlenbergia to include the other nine genera of the subtribe.
Abstract Nomenclature, taxonomy, synonymy, original publications, type collections, secondary ref... more Abstract Nomenclature, taxonomy, synonymy, original publications, type collections, secondary references using the accepted names, and distribution by country and Caribbean region within the New World are presented for taxa within four grass subfamilies: ...
Aphanelytrum peruviamim Sanchez Vega, P.M. Peterson, Soreng & Laegaard, sp. nov., is described an... more Aphanelytrum peruviamim Sanchez Vega, P.M. Peterson, Soreng & Laegaard, sp. nov., is described and illustrated. The new species occurs on rocky sites near Cerro Akumullca in Cajamarca, Peru and represents the second known species ascribed to Aphanelytrum. Aphanelytrum peruvianum differs from A. procumbens by having nerved glumes (1-2 mm long), narrow leaf blades (0.2-1.2 mm wide), shorter culms (14-24 cm tall), shorter internodes (3-13 mm long), shorter lemmas (2.2-3.5 mm long), and shorter anthers (2-2.9 mm long). A key and table comparing the salient features distinguishing A. peruvianum and A. procumbens is given. RESUMEN Se describe y se ilustra Aphanelytrum peruvianum Sanchez Vega, P.M. Peterson, Soreng <5r Laegaard, sp. nov. Esta nueva especie crece en sitios rocosos cerca del Cerro Akumullca en Cajamarca, Peru. Esta nueva entidad representa la segunda especie conocida atribuida al genero Aphanelytrum. Aphanelytrum peruvianum difiere de A. proeumbens en que tiene glumas nervadas (1-2 mm largo), laminas de la hoja estrechas (0.2-1.2 mm ancho), culmos mas cortos (14-24 cm alto), entrenudos mas cortos (3-13 mm largo), lemas mas cortas (2.2-3.5 mm largo), y anteras mas cortas (2-2.9 mm largo). Se incluye una clave y una tabla de comparacion de las caracteristicas mas sobresalientes que distinguen a A. peruvianum de A. procumbens. The genus Aphanelytrum (Hack.) Hack., established in 1902, was first named without a description by Sodiro (1889) with a single species, "A. decumbens Hack." (ex Sodiro, nom. nud.). Hackel (1887) initially described it as a subgenus of Brachyelytrum P. Beauv.; B. subgen. Aphanelytrum Hack., including a single new species B. procumbens Hack. Hackel (1902) subsequently recognized Aphanelytrum as a genus with the single species A. procumbens (Hack.) Hack., all based on a single collection of Sodiro's from Ecuador (Chase 1916). The placement and evolutionary relationships of Aphanelytrum have been somewhat controversial since its inception. It was originally placed in the subfamily "Festuceae" [Festucoideae], applied in the broad sense of Bentham (1881), Hackel (1887), and Hitchcock (1935). Hackel mistook the individual florets for glumeless single-flowered spikelets and placed Brachyelytrum within tribe Agrostideae, subtribe Stipinae. Agnes Chase (1916) reinterpreted the spikelet morphology, and placed the genus between the subtribes Melicinae and Centothecinae, which at that time were considered adjacent subtribes of the subfamily Festucoideae, tribe Festuceae. More recently, after major realignments of the classification of the Poaceae family (e.g. Clayton & Renvoize 1986), the genus was placed in the much more narrowly defined subfamily Pooideae (syn. Festucoideae), tribe Poeae (syn. Festuceae) near Poa (Clayton & Renvoize 1986). Aphanelytrum and Poa have very similar leaf anatomical characteristics, as well as multi-flowered, membranous spikelets with 5-nerved, keeled lemmas, glabrous ovaries, and caryopses with oval hilums (Clayton &t Renvoize 1986). It was specifically placed in subtribe Poinae (Soreng et al. 2003; Soreng et al. 2006) and seems to align near
SMITHSONIAN CONTRIBUTIONS TO BOTANY Muhlenbergia Schreb. (160), and Sporobolus R. Br. (160)). Ele... more SMITHSONIAN CONTRIBUTIONS TO BOTANY Muhlenbergia Schreb. (160), and Sporobolus R. Br. (160)). Eleven (about 29%) of the New World genera are monotypic.
To better understand the responses of arid-adapted, alpine plants to Quaternary climatic oscillat... more To better understand the responses of arid-adapted, alpine plants to Quaternary climatic oscillations, we investigated the genetic variation and phylogeographic history of Orinus, an endemic genus of Poaceae comprising three species from the dry grasslands of the Qinghai-Tibet Plateau (QTP) in China. We measured the genetic variation of 476 individuals from 88 populations using three maternally inherited plastid DNA markers (matK, rbcL and psbA-trnH), the biparentally inherited nuclear ribosomal internal transcribed spacer (nrITS) and amplified fragment length polymorphisms (AFLPs). We found that the plastid DNA, nrITS and AFLPs show considerable, recent differentiation among the species. We detected 14 plastid haplotypes (H1-H14), of which only three were shared among all species, and 30 nrITS ribotypes (S1-S30), of which one (S10) was shared between two species, O. kokonoricus and O. intermedius, but absent in O. thoroldii. The nrITS types formed clades that were inconsistent with species boundaries. Based on these data, we propose and illustrate a complex hypothesis for the evolutionary history of Orinus involving lineage sorting and introgression, the latter of which may explain the shared S10 nrITS type. The AFLP results showed clades corresponding to current species delineation and suggest that lineage sorting in the genus is probably complete. We estimated the crown age of Orinus to be 2.85 (95% highest posterior density: 0.58-12.45) Mya (late Pliocene), and subsequent divergence occurred in the Quaternary. Early divergences were allopatric. More recently, Orinus probably underwent regional expansions corresponding to Quaternary climatic changes, especially glaciation, which is consistent with our divergence time estimates. These climatic changes could have facilitated the S10 event and other hybridization events. Our data also suggest that species of this small genus of grasses survived the Quaternary glacial period in the extremely adverse habitats of the QTP.
Circumscriptions of and relationships among many genera and suprageneric taxa of the diverse gras... more Circumscriptions of and relationships among many genera and suprageneric taxa of the diverse grass tribe Poeae remain controversial. In an attempt to clarify these, we conducted phylogenetic analyses of >2400 new DNA sequences from two nuclear ribosomal regions (ITS, including internal transcribed spacers 1 and 2 and the 5.8S gene, and the 3'-end of the external transcribed spacer (ETS)) and five plastid regions (matK, trnL-trnF, atpF-atpH, psbK-psbI, psbA-rps19-trnH), and of more than 1000 new and previously published ITS sequences, focused particularly on Poeae chloroplast group 1 and including broad and increased species sampling compared to previous studies. Deep branches in the combined plastid and combined ITS+ETS trees are generally well resolved, the trees are congruent in most aspects, branch support across the trees is stronger than in trees based on only ITS and fewer plastid regions, and there is evidence of conflict between data partitions in some taxa. In plastid trees, a strongly supported clade corresponds to Poeae chloroplast group 1 and includes Agrostidinae p.p., Anthoxanthinae, Aveninae s.str., Brizinae, Koeleriinae (sometimes included in Aveninae s.l.), Phalaridinae and Torreyochloinae. In the ITS+ETS tree, a supported clade includes these same tribes as well as Sesleriinae and Scolochloinae. Aveninae s.str.
Based on morphological and molecular evidence we transfer the species of Trisetum sect. Trisetaer... more Based on morphological and molecular evidence we transfer the species of Trisetum sect. Trisetaera, T. hispidum, and Trisetokoeleria taymirica into Koeleria, describe Koeleria sect. Hispanica, and provide a new generic emendation. A total of 49 new combinations or new names are included. Additionally, we lectotypify Avena clarkei Hook f., Avena micans Hook. f., Avena subalpestris Hartm., Avena subspicata var. agrostidea Laest., Trisetum pubiflorum Hack., Trisetum spicatum f. minor Kom., and Trisetum spicatum f. umbrosum Kom. RESUMEN De acuerdo con diversas pruebas de carácter morfológico y molecular, transferimos las especies de Trisetum sect. Trisetaera, T. hispidum y Trisetokoeleria taymirica a Koeleria, describimos Koeleria sect. Hispanica y enmendamos la descripción de este género. Presentamos un total de 49 combinaciones o nombres nuevos. Además, designamos lectotipos para Avena clarkei Hook f., Avena micans Hook. f., Avena subalpestris Hartm., Avena subspicata var. agrostidea Laest., Trisetum pubiflorum Hack., Trisetum spicatum f. minor Kom. y Trisetum spicatum f. umbrosum Kom. Recently there has been considerable progress in the systematics of Trisetum Pers. [Poeae: Pooideae: Poaceae; type T. flavescens (L.) P. Beauv.], a group of perennials with a complicated taxonomic history due to the variability and overlapping morphologies of its species and infrageneric taxa (Randall & Hilu 1986; Finot 2010). Recent molecular phylogenetic studies indicate that
Based on morphological and molecular evidence we present new combinations or new names for 77 tax... more Based on morphological and molecular evidence we present new combinations or new names for 77 taxa of Cinnagrostis, seven taxa of Deschampsia, and 24 taxa of Peyritschia; and describe three new genera, Greeneochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Echinopogoninae), Paramochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Calothecinae), and Laegaardia P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Calothecinae) with two, two and one species, respectively. In addition to the 116 new taxonomic entities, we provide a key to the genera of American grasses presently or formerly treated in Calamagrostis or Deyeuxia and generic emendations for Cinnagrostis and Peyritschia. RESUMEN De acuerdo con evidencias de carácter morfológico y molecular se presentan nuevas combinaciones o nuevos nombres para 77 táxones de Cinnagrostis, siete táxones de Deschampsia y 24 táxones de Peyritschia, así como la descripción de tres nuevos géneros, Greeneochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribu Echinopogoninae), Paramochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribu Calothecinae) y Laegaardia P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribu Calothecinae) con dos, dos y una especie respectivamente. Además de las 116 nuevas entidades taxonómicas, proporcionamos una clave para los géneros de gramíneas americanas tratadas actual o anteriormente en Calamagrostis o Deyeuxia y enmendamos los genéros Cinnagrostis y Peyritschia. In a large unpublished molecular DNA sequence study using four gene regions (ITS, rpl32-trnL spacer, rps16-trnK spacer, and rps16 intron) we found most South American species of Deyeuxia Clarion ex P. Beauv. and Calamagrostis Adans., to align in a large clade excluding the type species of each of these genera (Peterson et al., in prep.). These results were largely corroborated by Saarela et al, (2010, 2017) in the study of Poeae R. Br. chloroplast group I where genera were split into Koeleriinae Asch. & Graebn. clade A (e.g. Koeleria Pers. and others) and Koeleriinae clade B (Cinnagrostis Griseb., Peyritschia E. Fourn., and others). We, therefore are resurrecting Cinnagrostis (Grisebach, 1874), a little known genus described from a single dichogamous species, C. polygama Peterson et al.: New grass combinations and names styles 2, stigmas feathery; lodicules 2, membranous, generally with 2 unequal lobes, glabrous or sometimes ciliate. Caryopses usually fusiform to oblong, sometimes laterally compressed, pericarp adherent, endosperm dry, pasty, or liquid. Basic chromosome number x = 7.
Based on morphological and molecular evidence we present new combinations or new names for 77 tax... more Based on morphological and molecular evidence we present new combinations or new names for 77 taxa of Cinnagrostis, seven taxa of Deschampsia, and 24 taxa of Peyritschia; and describe three new genera, Greeneochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Echinopogoninae), Paramochloa P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Calothecinae), and Laegaardia P.M. Peterson, Soreng, Romasch. & Barberá, gen. nov. (subtribe Calothecinae) with two, two and one species, respectively. In addition to the 116 new taxonomic entities, we provide a key to the genera of American grasses presently or formerly treated in Calamagrostis or Deyeuxia and generic emendations for Cinnagrostis and Peyritschia.
The original version of this Article contained an error in the title of the paper, where the word... more The original version of this Article contained an error in the title of the paper, where the word "polyploidization" was incorrectly given as "polypoidization". This has now been corrected in the PDF and HTML versions of the Article.
native to China. Mature, dry caryopses were examined with a low-power stereo microscope and the m... more native to China. Mature, dry caryopses were examined with a low-power stereo microscope and the most important characters were described for each species. When available, more than one accession was examined to study the variation, and additional accessions were drawn for certain species to show the variation. Consequently, the description and illustration for each species were derived from one to several accessions. The caryopses were drawn in four aspects: ventral, lateral, and dorsal views; and transverse section. Scanning electron microscopy (SEM) was conducted by direct mounting of the dry caryopsis on an aluminum stub and coating with gold palladium. Samples were then examined using SEM and photographed. The working classification adopted for the purpose of study arranges the genera according to genome (Table 1) starting with Elymus and includes the sometimes segregated genera Elytrigia, Leymus, and Psathyrostachys. Elymus is employed in a rather restricted sense and Aegilops and Triticum are treated as distinct. Sitanion and Hystri.x are tentatively included in Elymus because they share the same genome (Dewey, 1984:246-250; Love, 1982, 1984:447). Henrardia is included in the tribe in agreement with Hubbard (1946) and recent literature. Brachypodium is added to this study because Clayton and Renvoize (1986) included the genus in their treatment of the Triticeae and Macfarlane and Watson (1982) and Kellogg (1989) have recognized the genus as a sister group to the tribe. Acknowledgments.-We dedicate this paper to Regina O. Hughes in recognition of her long and distinguished career as a botanical artist, as well as for her accurate and artistic drawings that are presented here. Financial support during early parts of the study was provided by the
Evidence for global warming is inferred from spring advances in first-flowering in plants. The tr... more Evidence for global warming is inferred from spring advances in first-flowering in plants. The trend of average first-flowering times per year for the study group shows a significant advance of 2.4 days over a 30-year period. When 11 species that exhibit later first-flowering times are excluded from the data set, the remaining 89 show a significant advance of 4.5 days. Significant trends for earlier-flowering species range from •3.2 to •46 days, while those for later-flowering species range from-1-3.1 to-1-10.4 days. Advances of first-flowering in these 89 species are directly correlated with local increase in minimum temperature (Tf^in).
A new combination, Guadua chacoen¬ sis, is made. Based on morphological evidence, G. chacoensis a... more A new combination, Guadua chacoen¬ sis, is made. Based on morphological evidence, G. chacoensis appears closely allied to G. trinii. A detailed illustration of the species is included, and morphological descriptions and illustrations of the seedling and fruit are provided.
This paper provides several nomenclatural modifications based on a recent molecular study of Lept... more This paper provides several nomenclatural modifications based on a recent molecular study of Leptochloa. One generic transfer and four new varietal combinations are proposed for Dinebra Jacq. One orthographic correction and three new varietal combinations are provided in Diplachne P. Beauv. Two corrections are made for the specific epithets of Disakisperma. One orthographic correction is provided for Leptochloa.
Muhlenbergiinae are a subtribe in the grass (Poaceae) subfamily Chloridoideae, tribe Cynodonteae.... more Muhlenbergiinae are a subtribe in the grass (Poaceae) subfamily Chloridoideae, tribe Cynodonteae. The morphologically diverse group includes 10 genera and ca. 174 species and is restricted almost entirely to the New World, with a center of diversity in Mexico (125 species). With ca. 153 species, Muhlenbergia is by far the largest genus, and is divided into two subgenera, Muhlenbergia and Trichochloa, the latter with two sections. The other, much smaller genera are Aegopogon (4 species), Bealia (1), Blepharoneuron (2), Chaboissaea (4), Lycurus (3), Pereilema (4), Redfieldia (1), Schaffnerella (1), and Schedonnardus (1). We conducted a phylogenetic study of Muhlenbergiinae based on parsimony analysis of DNA sequences of the nuclear ribosomal internal transcribed spacer region (ITS1 + 5.8S + ITS2) and chloroplast trnL intron, trnL 3' exon, and trnL-trnF intergenic spacer. All genera were sampled, including 52 species of Muhlenbergia representing both subgenera and sections. Muhlenbergia and Pereilema are not monophyletic in the resulting trees. The species of Pereilema and the other small genera are nested within Muhlenbergia in three main lineages. One of the lineages includes a monophyletic Muhlenbergia subgen. Trichochloa. Another lineage comprises species having leaf anatomy predictive of the PCK subtype of C 4 photosynthesis. Based on the results of this study, we favor expanding the circumscription of Muhlenbergia to include the other nine genera of the subtribe.
Abstract Nomenclature, taxonomy, synonymy, original publications, type collections, secondary ref... more Abstract Nomenclature, taxonomy, synonymy, original publications, type collections, secondary references using the accepted names, and distribution by country and Caribbean region within the New World are presented for taxa within four grass subfamilies: ...
Aphanelytrum peruviamim Sanchez Vega, P.M. Peterson, Soreng & Laegaard, sp. nov., is described an... more Aphanelytrum peruviamim Sanchez Vega, P.M. Peterson, Soreng & Laegaard, sp. nov., is described and illustrated. The new species occurs on rocky sites near Cerro Akumullca in Cajamarca, Peru and represents the second known species ascribed to Aphanelytrum. Aphanelytrum peruvianum differs from A. procumbens by having nerved glumes (1-2 mm long), narrow leaf blades (0.2-1.2 mm wide), shorter culms (14-24 cm tall), shorter internodes (3-13 mm long), shorter lemmas (2.2-3.5 mm long), and shorter anthers (2-2.9 mm long). A key and table comparing the salient features distinguishing A. peruvianum and A. procumbens is given. RESUMEN Se describe y se ilustra Aphanelytrum peruvianum Sanchez Vega, P.M. Peterson, Soreng <5r Laegaard, sp. nov. Esta nueva especie crece en sitios rocosos cerca del Cerro Akumullca en Cajamarca, Peru. Esta nueva entidad representa la segunda especie conocida atribuida al genero Aphanelytrum. Aphanelytrum peruvianum difiere de A. proeumbens en que tiene glumas nervadas (1-2 mm largo), laminas de la hoja estrechas (0.2-1.2 mm ancho), culmos mas cortos (14-24 cm alto), entrenudos mas cortos (3-13 mm largo), lemas mas cortas (2.2-3.5 mm largo), y anteras mas cortas (2-2.9 mm largo). Se incluye una clave y una tabla de comparacion de las caracteristicas mas sobresalientes que distinguen a A. peruvianum de A. procumbens. The genus Aphanelytrum (Hack.) Hack., established in 1902, was first named without a description by Sodiro (1889) with a single species, "A. decumbens Hack." (ex Sodiro, nom. nud.). Hackel (1887) initially described it as a subgenus of Brachyelytrum P. Beauv.; B. subgen. Aphanelytrum Hack., including a single new species B. procumbens Hack. Hackel (1902) subsequently recognized Aphanelytrum as a genus with the single species A. procumbens (Hack.) Hack., all based on a single collection of Sodiro's from Ecuador (Chase 1916). The placement and evolutionary relationships of Aphanelytrum have been somewhat controversial since its inception. It was originally placed in the subfamily "Festuceae" [Festucoideae], applied in the broad sense of Bentham (1881), Hackel (1887), and Hitchcock (1935). Hackel mistook the individual florets for glumeless single-flowered spikelets and placed Brachyelytrum within tribe Agrostideae, subtribe Stipinae. Agnes Chase (1916) reinterpreted the spikelet morphology, and placed the genus between the subtribes Melicinae and Centothecinae, which at that time were considered adjacent subtribes of the subfamily Festucoideae, tribe Festuceae. More recently, after major realignments of the classification of the Poaceae family (e.g. Clayton & Renvoize 1986), the genus was placed in the much more narrowly defined subfamily Pooideae (syn. Festucoideae), tribe Poeae (syn. Festuceae) near Poa (Clayton & Renvoize 1986). Aphanelytrum and Poa have very similar leaf anatomical characteristics, as well as multi-flowered, membranous spikelets with 5-nerved, keeled lemmas, glabrous ovaries, and caryopses with oval hilums (Clayton &t Renvoize 1986). It was specifically placed in subtribe Poinae (Soreng et al. 2003; Soreng et al. 2006) and seems to align near
SMITHSONIAN CONTRIBUTIONS TO BOTANY Muhlenbergia Schreb. (160), and Sporobolus R. Br. (160)). Ele... more SMITHSONIAN CONTRIBUTIONS TO BOTANY Muhlenbergia Schreb. (160), and Sporobolus R. Br. (160)). Eleven (about 29%) of the New World genera are monotypic.
To better understand the responses of arid-adapted, alpine plants to Quaternary climatic oscillat... more To better understand the responses of arid-adapted, alpine plants to Quaternary climatic oscillations, we investigated the genetic variation and phylogeographic history of Orinus, an endemic genus of Poaceae comprising three species from the dry grasslands of the Qinghai-Tibet Plateau (QTP) in China. We measured the genetic variation of 476 individuals from 88 populations using three maternally inherited plastid DNA markers (matK, rbcL and psbA-trnH), the biparentally inherited nuclear ribosomal internal transcribed spacer (nrITS) and amplified fragment length polymorphisms (AFLPs). We found that the plastid DNA, nrITS and AFLPs show considerable, recent differentiation among the species. We detected 14 plastid haplotypes (H1-H14), of which only three were shared among all species, and 30 nrITS ribotypes (S1-S30), of which one (S10) was shared between two species, O. kokonoricus and O. intermedius, but absent in O. thoroldii. The nrITS types formed clades that were inconsistent with species boundaries. Based on these data, we propose and illustrate a complex hypothesis for the evolutionary history of Orinus involving lineage sorting and introgression, the latter of which may explain the shared S10 nrITS type. The AFLP results showed clades corresponding to current species delineation and suggest that lineage sorting in the genus is probably complete. We estimated the crown age of Orinus to be 2.85 (95% highest posterior density: 0.58-12.45) Mya (late Pliocene), and subsequent divergence occurred in the Quaternary. Early divergences were allopatric. More recently, Orinus probably underwent regional expansions corresponding to Quaternary climatic changes, especially glaciation, which is consistent with our divergence time estimates. These climatic changes could have facilitated the S10 event and other hybridization events. Our data also suggest that species of this small genus of grasses survived the Quaternary glacial period in the extremely adverse habitats of the QTP.
Circumscriptions of and relationships among many genera and suprageneric taxa of the diverse gras... more Circumscriptions of and relationships among many genera and suprageneric taxa of the diverse grass tribe Poeae remain controversial. In an attempt to clarify these, we conducted phylogenetic analyses of >2400 new DNA sequences from two nuclear ribosomal regions (ITS, including internal transcribed spacers 1 and 2 and the 5.8S gene, and the 3'-end of the external transcribed spacer (ETS)) and five plastid regions (matK, trnL-trnF, atpF-atpH, psbK-psbI, psbA-rps19-trnH), and of more than 1000 new and previously published ITS sequences, focused particularly on Poeae chloroplast group 1 and including broad and increased species sampling compared to previous studies. Deep branches in the combined plastid and combined ITS+ETS trees are generally well resolved, the trees are congruent in most aspects, branch support across the trees is stronger than in trees based on only ITS and fewer plastid regions, and there is evidence of conflict between data partitions in some taxa. In plastid trees, a strongly supported clade corresponds to Poeae chloroplast group 1 and includes Agrostidinae p.p., Anthoxanthinae, Aveninae s.str., Brizinae, Koeleriinae (sometimes included in Aveninae s.l.), Phalaridinae and Torreyochloinae. In the ITS+ETS tree, a supported clade includes these same tribes as well as Sesleriinae and Scolochloinae. Aveninae s.str.
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Papers by Paul Peterson