Tarasa Phil.
Contenido
Descripción
Annual herbs or subshrubs, decumbent, ascending, or erect in habit, stellatepubescent. Leaves petiolate, the blades triangular, rhomboid, or suborbicular, simple, lobed or parted , lacking foliar nectaries. Flowers usually in scorpioid cymes; involucel of (2-) 3 usually filiform bracts; calyx more or less accrescent, 5-lobed, stellate-pubescent, the hairs often stipitate (the stipe purplish); corolla purple or blue (rarely white); androecium included, the staminal column glabrous or pubes cent, antheriferous at apex, the anthers few (5-20); styles 6-13, the stigmas capitate. Fruits schizocarpic, the mericarps 6-13, apically usually aristate (sometimes merely apiculate), indehiscent or ventrally dehiscent, densely covered with stellate hairs, these often stipitate; seeds solitary, glabrous. Base chromosome number: x = 5A
Discusión taxonómica
Tarasa is a South American genus of ca. 30 species that occur principally at elevations of 2200 to 3800 m from Chile and Argentina to Peru. Two species occur in Mexico as disjuncts.A