Leaf morfology and anatomy of Argyrochosma nivea (Poir.) Windham var. nivea (Pteridaceae) in an altitudinal gradient in the Northwestern Argentina

Abstract

Hernández Marcela, Patricia Albornoz, María Eugenia Guantay y Omar Varela. 2005. Leaf morfology and anatomy of Argyrochosma nivea (Poir.) Windham var. nivea (Pteridaceae) in an altitudinal gradient in the Northwestern Argentina. Lilloa 42 (1-2). This study describes and analyses the leaf morphology and anatomy of Argyrochosma nivea (Poir.) Windham var. nivea (Pteridaceae) in an altitudinal gradient from 1000 to 4960 above sea level in the Northwestern Argentina. The study has been done with fresh and herborized plants. Transversal sections and diaphanization of the pinnules have been by means of conventional techniques and stains. The leaf morphology does not show significant differences from the original description. Anatomically, the leaf is dorsiventral and hypostomatic with anisocytic and polocytic type stomata. Glandular trichomes secrete wax in the abaxial epidermis. The stem is terete with protostelic vascular bundle, xylem Y-shaped. The statistical analysis shows that the trichome index correlationates positively with height, while an opposite relationship was found for the stomatic index. The leaf anatomy of this species is described for the first time and the altitudinal distribution range is increased in this variety.