Two New Species of Chusquea (Poaceae, Bambuseae) from Northwestern Argentina

Abstract

Chusquea Kunth (Poaceae, Bambusoideae, Bambuseae) is the largest bamboo genus in the world. Approximately 13 species of Chusquea occur in the southern Andes of Argentina and Chile and all of them are endemic. In the present work, two new species found in high-altitude grasslands of the Andes mountain range in northwestern Argentina, Chusquea egluma and Chusquea floribunda, are described and illustrated. Morphological and anatomical characters are described and two identification keys for the Andean Chusquea species from northwestern Argentina are provided, one based on morphological characters (vegetative and reproductive), and the other on anatomical characters (culm and leaf epidermis and cross section). The new taxa and related species are compared in tables based on characters of taxonomic value.Resumen-Chusquea Kunth (Poaceae, Bambusoideae, Bambuseae) es el ge ´nero de bambu ´es ma ´s grande del mundo. Aproximadamente, 13 especies de Chusquea habitan en los Andes australes de Argentina y Chile, y todos ellos son ende ´micos. En el presente trabajo, se describen e ilustran dos nuevas especies de bambu ´es len ˜osos que habitan en pastizales de altura en los Andes del noroeste de la Argentina, Chusquea egluma y Chusquea floribunda. Se describen caracteres morfolo ´gicos y anato ´micos, y se presentan dos claves de identificacio ´n de las especies andinas de Chusquea del noroeste de la Argentina, una basada en caracteres morfolo ´gicos (vegetativos y reproductivos) y otra, en caracteres anato ´micos (epidermis y seccio ´n transversal caulinar y foliar). Se presentan tablas comparativas de caracteres de valor taxono ´mico de los nuevos taxones y especies relacionadas.

The Catalogue of Vascular Plants of the Southern Cone and the Flora of Argentina: their contribution to the World Flora

“…There are several possible causes to explain this variation: description of new taxa, record of new occurrences for the area or adjustment of taxonomic circumscription at all levels, often as a result of new taxonomic and phylogenetic research. Therefore the species number accepted within a certain genus may decrease when new synonymies are proposed, as seen in genus Phyla L. (O'Leary & Múlgura 2012) or it may increase through the description of new species, as was the case with Chusquea Kunth, through the description of Chusquea egluma Guerreiro & Rúgolo and Chusquea floribunda Guerreiro & Rúgolo in 2013(Guerreiro & Rúgolo de Agrasar 2013. The number of genera may increase through segregation of a group of species to another genus, as seen in 2014 for Panicum validum Mez that was split from Panicum L. and placed within the new genus Osvaldoa J.R. Grande (Grande Allende 2014), causing an increase in the number of genera in the Poaceae.…”

Evolution of the bamboos (Bambusoideae; Poaceae): a full plastome phylogenomic analysis

“…The New World Chusqueinae also exhibited a higher substitution rate in our ML analyses. While some species within Chusqueinae flower as infrequently as once every 70 years, flowering intervals are extremely variable in this lineage [ 26 - 28 ]. Chusquea spectabilis was formerly classified within the genus Neurolepis, which has shorter flowering intervals correlating with higher altitude habitats [ 29 ].…”

Revalidation of Chusquea argentina (Poaceae, Bambusoideae, Bambuseae) on the basis of morphological, anatomical and phenological characters

“…Chusquea Kunth (1822: 151) is the most diverse woody bamboo genus in the world; it comprises ca. 163 species (Bamboo Phylogeny Group 2012, Costa da Mota et al 2013, Guerreiro & Rúgolo de Agrasar 2013. The genus is distributed from Mexico to Argentina and Chile from sea level to over 4000 m. The species of Chusquea are often significant, sometimes dominant, components of montane forest and high altitude grassland vegetation, where they can be aggressive colonizers (Judziewicz et al 1999).…”