Sidastrum Baker f.
Contenido
Descripción
Erect subshrubs 1-2 m tall, more or less stellate-pubescent. Leaves petiolate to subsessile, the blades lanceolate or ovate to elliptic, serrate or crenate, acute or obtuse, lacking foliar nectaries; stipules subulate, erect. Flowers solitary in the leaf axils, in short axillary racemes, or forming ample terminal panicles or racemes; pedicels long or short, sometimes capillary, the individual pedicels often subtended by three stipuliform bractlets; involucel absent; calyx small, cupuliform, ecostate, 5-lobed; petals small, white, yellow, or orange (purple in one species); androecium included (though petals reflexed in one species), antheriferous at apex, the anthers few (5-20); styles 5~10, slender, the stigmas capitellate. Fruits schizocarpic, oblate to conical, often stellate-pubescent, smooth or rugulose; mericarps 5-10, essentially indehiscent, trigonal, smooth or somewhat reticulate laterally; seeds solitary, sparsely pubescent to subglabrous. Base chromosome number: x = 16.A
Discusión taxonómica
Sidastrum currently comprises seven Neotropical species from the West Indies and Mexico to South America. Four species occur in Mexico (Figs. 103, 106), three of them endemic to that country. Additional studies will probably require the enlargement of the genus to include a number of other species, especially from Australia, that have previously been assigned to Sida.A