Estudo comparativo de flores casmógamas, cleistógamas e de frutos de Camarea affinis St.-Hil. (Malpighiaceae) Comparative study of casmogamous and cleistogamous flowers and Camarea affinis St.-Hil. fruits (Malpighiaceae)

O gênero Camarea pertence a tribo Gaudichaudieae caracterizada pela redução no número de elementos do androceu, gineceu parcialmente sincárpico, estilete único e ginobásico e pela ocorrência de flores cleistógamas. Neste trabalho é feito o estudo de Camarea affinis St-Hil. no que se refere à morfologia e á anatomia de flores casmógamas e cleistógamas, assim como de seus respectivos frutos.<br>The genus Camarea belongs to the tribe Gaudichaudieae, which is traditionally characterized by a solitaiy gynobasic style, presence of veiy reduced cleistogamous flowers, an androecium of 6 staminal elements and carpels only partially united. This paper presents information about the morphology and the anatomy of chamosgamous and cleistogamous flowers and fruits of Camarea affinis St Hi

Arid and Semiarid Rangelands of Argentina

Two thirds of continental Argentina are arid and semiarid rangelands. These rangelands include five phytogeographic regions: (1) Puna, (2) Chaco Occidental, (3) Monte, (4) Caldenal, and (5) Patagonia. This review includes and begins with a brief overview of the climate, soil, and vegetation characteristics of each region. After that, the major causes of degradation or desertification of these territories are indicated, together with the previous and current impacts on the water resources; the physicochemical and biological soil characteristics, and vegetation structure; productive activities; economy; and society. Fortunately, in contrast with various other arid and semiarid regions in the world, a threshold of losses of renewable natural resources has not yet been reached as a result of such degradation or desertification of the study ecological systems. Beyond this threshold, reestablishment of benefits which could have been obtained from rational (not abusive) utilization of those resources will be impossible. Our aim is an improved land use that allows sustainable production, the magnitude of which will depend upon its previous degree of degradation or desertification.Fil: Busso, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Fernandez, Osvaldo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; Argentin