Oral Paper

         Floristics & Taxonomy

A new species of Chusquea subg. Swallenochloa (Poaceae: Bambusoideae) from the high Andes of Peru

Presenting Author
Nancy Refulio Rodriguez
Description
Chusquea, a woody bamboo genus native to the New World, consists of ca. 203 recognized species that are found mainly in Brazil and the Andes. About 33 described species of Chusquea are known from Peru, representing four of its five subgenera. Chusquea subg. Swallenochloa (McClure) L.G. Clark, characteristically inhabiting high elevation grasslands, is represented by eight species in Peru, seven of which are considered endemic. In Peru, Chusquea subg. Swallenochloa ranges in elevation from 2,800 to 3,800 m. While the number of recognized species in Chusquea has increased considerably in recent years, further substantial taxonomic work is needed to better integrate collections with uncertain placement into their appropriate taxonomic ranks, especially collections from the Peruvian Andes. After morphological and anatomical examination of specimens collected in Rio Abiseo National Park (La Libertad department, northern Peru) and the Otishi National Park (Junin department, central Peru), which were considered in a recent study as one of 11 different sets of Incertae Sedis specimens within Chusquea sect. Swallenochloa, we describe them as a new species, C. crassimarginalis. This new species resembles C. depauperata because of its fistulose culms, slightly falcate spikelets, subulate foliage leaf blades, anatomy of the foliage leaf blade with a simple midrib and absent fusoid cells, abaxial epidermis of foliage leaf blade with abundant rounded simple and branched papillae, and stomatal apparatuses obscured by abundant papillae. Chusquea crassimarginalis differs from C. depauperata in having glume I (sometimes absent) and glume II developed, culm leaf blades less than 1.5 mm long, corrugated foliage leaf blades, foliage leaf blade cross sections with a prominent, adaxially projecting rib associated with first and second order vascular bundles, and a mesophyll adjacent to the bulliform cells with five to six layers of rosette cells. If most or all of the remaining 10 sets of Incertae Sedis specimens of Chusquea subg. Swallenochloa in Peru represent new species, we can expect its known diversity to double with additional taxonomic effort.