Malachra L.
Contenido
Descripción
Erect herbs or subshrubs, sometimes puberulent, more commonly hispid, often with urticating hairs. Leaves petiolate, the blades suborbicular to broadly ovate, angular, palmately lobed to digitately divided, truncate, serrate, acute to obtuse, usually pubescent, lacking foliar nectaries; stipules filiform, relatively persistent. Flowers in condensed, bracteate, headlike racemes, the “heads” axillary or terminal, sessile or pedunculate; specialized bracts subtending the inflorescence broadly cordate-ovate, sessile or subsessile, basally often with prominent nerves alternating with white intercostal tissue, distally green and foliaceous, often dissected or setose basally; involucel absent (present in M. radiata); calyx small, deeply 5-lobed; corolla white, yellow, or lavender, often inconspicuous; androecium included, the staminal column with 5 apical teeth; styles 10, the stigmas capitate. Fruits schizocarpic, glabrous or puberulent; mericarps 5, usually smooth or reticulately costate, 1-seeded; seeds glabrous. Base chromosome number: x = 28.A
Discusión taxonómica
Malachra is a Neotropical genus of perhaps eight to ten species, of which four occur in Mexico. Its occurrence in the Old World is probably a result of relatively recent introduction.A