Resumen

RZEDOWSKI, Jerzy; CALDERON DE RZEDOWSKI, Graciela  y  PEREZ-CALIX, Emmanuel. Tetrachyron Omissum and Trigonospermum alexandri, two new species of Compositae-Heliantheae from the central part of Mexico. Act. Bot. Mex [online]. 2008, n.84, pp. 1-8. ISSN 0187-7151.

Tetrachyron omissum and Trigonospermum alexandri are illustrated and described as new species. The first grows in northeastern Querétaro and is related to T. websteri (Wussow & Urbatsch) B. L. Turner. The second is an aquatic or subaquatic plant known only from two pools in the vicinity of the town of Santa Clara del Cobre in northern Michoacán. It is possibly related to T. adenostemoides Less.

Palabras llave : México; Michoacán; Querétaro; Tetrachyron; Trigonospermum.