Format: ORAL

Lynn G. Clark1, Nancy F. Refulio-Rodriguez1

1 Department of EEOB, Iowa State University, USA

Although bamboos (Bambusoideae) are typically associated with the Eastern Hemisphere, especially China, India and Japan, 600 bamboo species (of over 1700) are native to the Americas. Of these, 203 (one-third) belong to Chusquea, the most diverse genus of bamboo, and the description of new species in this genus continues unabated. Chusquea is the most widespread bamboo genus in the Americas, extending from 2540N in Mexico to 47S in Chile and Argentina. Species of Chusquea grow primarily in montane forests and high elevation grasslands in Mesoamerica, the Greater Antilles, the Andes and eastern Brazil, and are often dominant elements in these habitats. Chusquea has the broadest elevational range of any bamboo genus, from sea level to over 4300 m, although few of its species occur below 1000 m. Morphologically, Chusquea has a uniform spikelet structure of four glumes and one fertile floret with no rachilla extension, but exhibits extreme vegetative diversity, from aerially unbranched culms bearing leaves to 4 m long and 30 cm wide to highly branched culms with 2-200 subsidiary branches per node, bearing leaves 1-40 cm long and 0.06-8.5 cm wide. Understanding of the complex evolutionary history of the woody bamboos, which involves ancient hybridization and polyploidy, has been enhanced by recent genomic-level analyses, but no WGS resources for Chusquea are available. Elucidation of species-level diversification has been hampered by lack of resolution in plastid sequence data but also likely rapid and recent radiation in the Euchusquea clade and homoploid hybridization. We are exploring the utility of nuclear target capture data (Angiosperms353) to study the evolution of this diverse and ecologically important genus. Questions include revisiting the apparent paraphyly of Neurolepis relative to Chusquea, testing the monophyly and relationships of morphologically defined groups within Chusquea, and unraveling the biogeographic history of the genus.