SYSTEMATIC AND BIOGEOGRAPHIC STUDIES ON THE GENUS ALONSOA RUIZ & PAV. (HEMIMERIDEAE, SCROPHULARIACEAE)

O'LEARY NATALY; OLMSTEAD, RICHARD

Quito

Congreso; XII Congreso latinoamericano de Botánica; 2018

Asociación Latinoamericana Botánica

Tribe Hemimerideae Benth. is a small tribe of 6 genera and ca. 134 species of annual and perennial plants: Alonsoa Ruiz & Pav., Colpias Benth., Diascia Link & Otto, Diclis Benth., Hemimeris L., and Nemesia Vent., found mainly in tropical and southern Africa, except Alonsoa, present in south Africa and mainly in the Andean regions of central and south America. Some authors united all the genera from tribe Hemimeridae because of the presence of a rotate o short-tubed corolla bearing one or two sacs, spurs or furrows, this structure being an adaptation to pollination by a specialized group of bees. Alonsoa reunites mostly perennial herbs and shrubs, exhibiting interesting differences among the species in pollination biology, probably related to its amphi-Atlantic distribution. The number of recognized valid taxa within Alonsoa is very inconstant and varies from 5 species to almost 65 taxa, all these different numbers proof the need for a comprehensive treatment of the genus. Some authors have even divided Alonsoa species into two subgenera because of differences in stigma and stamen morphology. The objectives of this study are to propose a modern taxonomic revision of Alonsoa and to analyze the phylogenetical relationship between the species of Alonsoa and the related genera from tribe Hemimerideae, checking monophyly of the genus. Furthermore we intend to perform biogeographical studies, analyzing dispersion routes and timing of dispersal, and we plan to examine pollination mechanisms and its optimization as an important morphological trait on the revealed phylogenies. Advances on this subject are being here presented. Preliminary studies evidence the presence of ca. 32 recognized valid taxa, being Alonsoa meridionalis (L. f.) Kuntze one of the most amply distributed taxa, ranging from southern south America to southern north America.