Angélica Martínez-Bernal

Mimosa tejupilcana, a New Species of series Plurijugae (Leguminosae) from the State of Me&xico, Mexico

Mimosa tejupilcana, a new species from the State of Mexico, Mexico, is described and illustrated. It is presently known only from the Municipios of Valle de Bravo, Temascaltepec, Tejupilco de Hidalgo, and Amatepec. The new species is referred to series Plurijugae and that series is placed in sect. Mimosa. A key to distinguish the new species from all other taxa in the series, as well as from the similar M. adenantheroides, is provided.

Crop and non-crop productivity in a traditional maize agroecosystem of the highland of Mexico

BackgroundIn Mexico, the traditional maize cultivation system has resisted intensification attempts for many decades in some areas, even in some well-connected regions of the temperate highlands. We suggest that this is due to economics.MethodsThe total useful biomass of several fields in Nanacamilpa, Tlaxcala, are evaluated for productivity and costs.ResultsMaize grain production is low (1.5 t ha-1) and does not cover costs. However, maize stover demands a relatively high price. If it included, a profit is possible (about 110 US

Comparative study of pollen morphology and exine ultrastructure in tetrads, octads and polyads of the genus Mimosa (Leguminosae)

ha-1). We show that non-crop production (weeds for food and forage) potentially has a higher value than the crop. It is only partially used, as there are constraints on animal husbandry, but it diversifies production and plays a role as a back-up system in case of crop failure.ConclusionThe diversified system described is economically rational under current conditions and labor costs. It is also stable, low-input and ecologically benign, and should be recognized as an important example of integrated agriculture, though some improvements could be investigated.

MORFOLOGÍA DEL POLEN DE MIMOSA SERIE QUADRIVALVES (LEGUMINOSAE, MIMOSOIDEAE)

ABSTRACT This is the first study of exine ultrastructure to be performed in five endemic Mexican Mimosa taxa (M. pringlei var. pringlei, M. calcicola, M. spirocarpa, M. caerulea and M. sousae), one occurring in Mexico and Central America (M. occidentalis), one widely distributed throughout the neotropics (M. setosa var. paludosa), and two in South America (M. irrigua and M. daleoides). Mimosa pollen grains are associated in polyads (12 grains), octads and tetrads. Polyads and octads in members of the basal clade of Mimosa phylogeny (sect. Mimadenia) evince the affinity of Mimosa with Piptadenia. Octads are retained in sect. Batocaulon and tetrads are evolved in this section. More recent clades (sect. Habbasia, Mimosa and Calothamnos) only show tetrads varying in size and shape. Polyads show greater variation in the exine layers, with a bistratified granular structure. Octads display a columellar-granular infratectal structure while tetrads in sect. Mimosa exhibit a less variable exine with a granular infratectal structure.