Abstract Detail

Systematics

Clark, Lynn [1], Mota, Aline [2], Vidal, Kaio Vinicius de Araujo [3], Oliveira, Reyjane Patricia de [3].

Systematics and Evolution of Chusquea subg. Rettbergia (Poaceae: Bambusoideae: Bambuseae).

With 175 described species, Chusquea is the most diverse currently recognized genus of woody bamboo (Poaceae: Bambusoideae). Chusquea is defined by the putative synapomorphies of two papillae per subsidiary cell and a spikelet consisting of four glumes and one fertile floret with no rachilla extension. Molecular data strongly support the monophyly of Chusquea and its four constituent major lineages: Chusquea subg. Magnifoliae (10 species) + {Chusquea subg. Platonia (13 species) + [Chusquea subg. Rettbergia (15 species) + the Euchusquea clade (137 species)]}. Chusquea subg. Rettbergia + the Euchusquea clade share the presence of multiple, dimorphic buds per node, with one large central bud subtended or flanked by two to many smaller subsidiary buds. Chusquea subg. Rettbergia previously was thought to include as many as 30 Brazilian species, but recent molecular and morphological analyses support this lineage as a group of 15 described and two undescribed species defined by the combination of strongly infravaginal branching, a well-developed girdle on the culm leaves, a circular, dome-shaped central bud, geniculate subsidiary branches, and a connate lemma apex. Members of this subgenus are scandent and clambering, some to the extent of forming curtains that completely cover smaller trees and shrubs. Thirteen of the described and the two undescribed species are confined to the Atlantic forests of eastern and southeastern Brazil, with one species endemic to Bolivia and another endemic to Colombia. Chusquea mirabilis, endemic to Bahia, Brazil, is supported as sister to the rest of the subgenus based on ITS and plastid markers. The Colombian species is embedded in a polytomy of other Brazilian species of the subgenus, indicating at least one long-distance dispersal event in the evolution of this group (the Bolivian species has not yet been sampled in a molecular analysis). Chusquea bambusoides and C. oligophylla are the most common and widespread species of subg. Rettbergia, with C. pulchella (southern São Paulo state, Brazil) and C. arachniformis (Antioquia, Colombia) known from one population each. Some species in subg. Rettbergia appear to have gregarious flowering cycles of 15-16 years, whereas others appear to flower sporadically or frequently without a defined cycle.

1 - Iowa State University, Department Of Ecology, Evolution, And Organismal Biology, 251 Bessey Hall, Ames, IA, 50011-1020, USA
2 - University of Pernambuco, Biological Sciences, BR 203, Km 2 s/n, Vila Eduardo, Petrolina, Pernambuco, 56.328-903, Brazil
3 - State University of Feira de Santana, Laboratory of Plant Molecular Systematics, Av. Transnordestina s/n, Feira de Santana, Bahia, 44036-900, Brazil

Keywords:
Atlantic forest
Chusqueinae
Neotropical woody bamboos.

Presentation Type: Oral Paper
Session: 14, Systematics I: Basal Dicots, Monocots & Rosids
Location: Sundance 1/Omni Hotel
Date: Monday, June 26th, 2017
Time: 3:15 PM
Number: 14008
Abstract ID:423
Candidate for Awards:None