Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Based on an intense fieldwork, on the critical review of the specimens of Asteraceae held in three important Mexican herbaria, as well as the study of specialized literature, a checklist of the Asteraceae of the state of Zacatecas is provided. The checklist includes 141 genera, 456 species, and 119 infraspecific taxa, distributed in 14 tribes. The tribes with the largest number of taxa are Heliantheae (50 genera and 149 species), Astereae (22 and 68), and Eupatorieae (17 and 96). The most diverse genera are Stevia (27 species), Ageratina (23), Brickellia (21), Viguiera (15), Verbesina (14), Pseudognaphalium (13) and Acourtia (12). Fifty four percent of the species occurring in Zacatecas are endemic to Mexico, four of them plus one variety are restricted to the political boundaries of the state. The largest number of endemisms are shared with Durango and Jalisco, two neighbor states. In Zacatecas the Asteraceae constitute the most diversified family of flowering plants. Its richness is largely the result of the confluence in the state of four physiographic provinces (Sierra Madre Occidental, Sierra Madre Oriental, Central Plateau and Transvolcanic Belt), as well as of the confluence of the Holarctic and Neotropical Floristic Kingdoms.

Aristolochia colimensis is a new species described for the state of Colima, México. This species differs from related taxa of the subsection Pentandrae (A. brevipes Benth., A. occidentalis Santana-Michel et S. Lemus, A. oaxacana Eastwood and A. pringlei Rose) in its reflexed calyx limb at anthesis and in the utricle with a gibba on its upper part.

During preparation of the treatment of Portulacaceae for Flora del Bajío y de Regiones Adyacentes, it was determined that some species situated in genus Talinum require transfer to Phemeranthus, so in this paper the following new combinations are proposed: P. mexicanus (Hemsley) G. Ocampo, P. multiflorus (Rose & Standley) G. Ocampo and P. napiformis (DC.) G. Ocampo. In addition, the description for P. mexicanus is enlarged.

Eleocharis obtusetrigona (Lindl. & Nees) Steud., previously known only from South America, is recorded here for southeastern United States, Mexico and Central America. A description of the species is presented, as well as a key to separate E. obtusetrigona from other robust species of subgenus Limnochloa with which it has been confused.

Ribes grandisepalum, a shrub that lives in the forest of Abies in the state of Michoacan, Mexico, is proposed as a new species to science. The new taxon belongs to subgenus Coreosma section Calobotrya (Spach) Jancz. (Grossulariaceae) and is related to Ribes pringlei Rose. It is distinguished by its glandular-pubescent sepals that reach sizes of 5.5-8.5 mm in length, pedicels 7-17 mm in length and the ovary and fruit with glandular hairs.

Bursera heliae and B. isthmica are described as new and illustrated. The  distribution of both seems to be restricted to the southeastern part of the Mexican state of Oaxaca. The first one is related to B. cuneata (Schlecht.) Engl., while the second is linked with B. glabra (Jacq.) Tr. & Planch. and with B. ribana Rzed. & Calderón. A list of additional 30 species of Bursera known from Oaxaca is included.

Genlisea filiformis A.St.-Hil. is reported for the first time from Mexico. Its distinctive characters, as well as information on its habitat and geographic distribution are presented.

La Dra. Helia Bravo Hollis ha sido sin duda alguna pilar de la botánica mexicana del siglo XX. Dedicó más de 50 años de su  vida académica a consolidar estudios sobre florística y  taxonomía, con particular énfasis en las cactáceas de México,  por lo que se convirtió en la especialista más reconocida para ese grupo de plantas.

The vacuole, occupying up to 95% of the volume of a mature higher plant cell, serves as a main store of solutes and as the key element of intracellular Ca2+- and pH-stat. The role of the vacuole in the ionic homeostasis of the cell is also evident under K+-starving conditions and under salt stress. It is involved in the regulation of turgor and cell volume, and in specialized cells, such as stomatal guard cells, a large central vacuole is a principle component of the cell osmotic motor. For more than a decade, the guard cell has gained the status of a higher plant cell model, intensely studied by physiological, cell and molecular biology techniques. Despite tremendous progress in the understanding of signal transduction events taking place at plasma membrane of guard cells, the involvement of vacuolar ion transporters remains a significant challenge. Like in a plasma membrane, the ionic transport across the vacuolar membrane, the tonoplast, is directed and coordinated through a complex set of specific transport proteins, including pumps, transporters, and ionic channels. During recent years, the application of modern electrophysiological techniques (principally, the patch-clamp) has enabled numerous individual ion channels to be functionally characterized, although none of them has been structurally identified. The work of our group is focused on the characterization of so called slow (SV) and fast (FV) vacuolar ion channels, which have a wide, if not ubiquitous, distribution in higher plants, and can be detected in stems, leaves, as well as in root storage tissue. Their ionic selectivity, gating by membrane voltage and by physiologically abundant cations, as well as their possible roles in signal transduction and ionic balance are discussed.

Hobsonia mirabilis (Peck) Linder, a helicosporous fungus, is recorded for the first time from Mexico. This saprobic, leaf litter species forms white, gelatinous sporodochia on decaying vegetation. The fungus is described and illustrated in situ, and additional information on its morphology in culture is presented. Results of tests of its ability to grow on several carbon sources are also presented.