Morfología y anatomía foliar comparada de Chuquiraga y géneros afines (Asteraceae)

Abstract

Chuquiraga is a genus of evergreen shrubs endemic to the arid and semiarid regions of the Andes and southern South America. It is the most variable morphologically of the subfamily Barnadesioideae and presents a great diversity of leaf types. The genus has been classified into two sections based on this morphological variation: Chuquiraga and Acanthophylla. Within section Chuquiraga, two series, Chuquiraga and Parviflorae, have been recognized taking into account variation in size of capitula. The objetive of this study was to conduct a comparative study of the morphology and anatomy of leaves of 19 of the 22 species of Chuquiraga, and four species of some of its related genera (Dasyphyllum, Doniophyton, and Duseniella). Our results indicate that four morpho-anatomical leaf types can be distinguished within Chuquiraga: 1) flat, dorsiventral and hypostomatic, 2) flat, isolateral and amphistomatic, 3) boat-shaped, isolateral and epiestomatic and, 4) acicular, dorsiventral inverted and epistomatic. These leaf types can be correlated with sections Chuquiraga (Types 1 and 2) and Acanthophylla (Types 3 and 4), supporting the traditional classification of the genus. In contrast, series Chuquiraga and Parviflorae cannot be distinguished on the basis of the observed leaf characteristics. Finally, leaf morphology and anatomy were useful to distinguish Chuquiraga from related genera of Barnadesioideae. The four genera studied present different xeromorphic characteristics in their leaf morphology and anatomy.