Análisis preliminar sobre anatomía del le？o de 11 especies de la tribu Heliantheae (Asteraceae) de Los Andes venezolanos

the secondary xylem anatomy of eleven species of the heliantheae tribe (asteraceae) growing in the venezuelan andes is described. the species described are carramboa badilloi, c. littlei, c. pittieri, c. rodriguezii, c. tachirensis, c. trujillensis, libanothamnus granatesianus, l. neriifolius, l. occultus, montanoa quadrangularis and ruilopezia marcescens. m. quadrangularis is easy to separate from the others because it has septate fibres, exclusively simple perforation plates, pores with mean diameters greater than 100 mm and less than 20 pores/mm2. species from carramboa, libanothamnus and ruilopezia (espeletiinae subtribe) have remarkable similitude among them. the mean features to differentiate them are related with intervessel and ray-vessel pits. ruilopezia have wood anatomical features intermediate between carramboa and libanothamnus. we found sheath cells in c. littlei, c. pittieri, l. granatesianus and m. quadrangularis. the presence of growth rings was observed only in l. occultus. a dichotomous key for wood identification is included.