Las plántulas de Ficus, subgénero Pharmacosycea (Moraceae), en Veracruz, México

The germination and morphology of seedlings of the following five species of Ficus subgenus Pharmacosycea, from Veracruz are described: Ficus insipida Willd., F. lapathifolia (Liebm.) Miq., F. maxima Mill., F. patenensis Lundell y F. yoponensis Desv. The five taxa have epigeal seedlings (phanerocotylar or Macaranga type). The germination in all species occurred within three weeks. The seedlings characteristics are very similar and do not permit the separation of species. The presence of hydathodes in the leaf margins is reported for the first time in the subgenus Pharmacosycea.Se describe e ilustra la germinación y morfología de las plántulas de cinco especies de Ficus subgénero Pharmacosycea, nativas de Veracruz: Ficus insipida Willd., F. lapathifolia (Liebm.) Miq., F. maxima Mill., F. patenensis Lundell y F. yoponensis Desv. Los cinco taxa presentaron plántulas epígeas (fanerocotilares o del tipo Macaranga), germinando en un máximo de tres semanas, sin permitir la caracterización a nivel de especie. Se documenta por primera vez la presencia de hidátodos en los márgenes de las hojas para los miembros del subgénero Pharmacosycea

Landscape variation of liana communities in a Neotropical rain forest

We studied local and landscape variation of liana communities across habitats differing in soil and topography in the Lacandon tropical rain forest, southeast Mexico. All liana stems greater than or equal to1 cm diameter breast height (DBH) were sampled within each one of eight 0.5 ha plots. Two plots were sampled in each of the following habitats: alluvial-terrace, flood plain, low-hill, and karst-range. In the whole sampled area, we recorded 2092 liana stems ha(-1) representing a total basal area of 1.95 m(2) ha(-1) and 90 species within 34 families. Lianas showed a strong clumped spatial pattern and a high taxonomic diversity at the scale of 50 m(2). On average (+/- s.e.), we found 10.4 +/- 0.6 stems, 4.4 +/- 0.2 species and 3.4 +/- 0.2 families per 50-m(2) quadrat. Bignonaceae (19 species), Malpighiaceae (9), and Fabaceae (8) comprised about 40% of total number of recorded species, and almost 50% of the total liana biomass, as expressed by an importance value index that combines species relative abundance, spatial frequency and basal area. Nineteen families (56%) were represented by just one species and Cydista (Bignoniaceae) and Machaerium (Fabaceae) were the most diverse genera with four species each. In the landscape, lianas showed a geometric diversity-dominance relationship with only three species (Combretum argenteum, Hiraea fagifolia and Machaerium floribundum) accounting for more than 50% of total biomass. More than 30% of the species were rare (\u3c15 stems ha(-1)) and showed low spatial frequency (recorded in just one of the eight plots). Liana communities differed in structure and composition among sites and habitats. Among sites, lianas exhibited four-fold variation both in stem density and basal area and two-fold variation in species richness. Liana density was significantly and positively correlated with treefall disturbance. Ordination analysis indicated a strong habitat differentiation of lianas at the family and species levels. Most species with non-random distribution among habitats (69% from 25 species) were significantly most abundant in low-hill or flood plain sites, and some (12%) were preferentially found at the karst-range sites. The karst-range habitat was well differentiated from the others in species composition and structure, and shared only 50% of common species with other habitats

Liana diversity and reproductive attributes in two tropical forests in Mexico

We describe liana diversity and variation in morphology of flowers and diaspores in two tropical forests in Mexico: a seasonally deciduous forest at Chamela, Jalisco and a lowland rain forest at Chajul, Chiapas. Flowers were classified as inconspicuous (le1 cm in length and white or pale green flowers) or conspicuous (\u3e 1 cm and brightly colored flowers). Dispersal syndrome was classified as anemochory, barochory, and zoochory. We recorded a higher number of lianas species in Chajul (128 spp.) than in Chamela (71 spp.). In both sites, families with the highest number of species were Bignoniaceae, Leguminosae, Sapindaceae, and Malphigiaceae, and almost half of the liana species had inconspicuous flowers. Most of the species had an abiotic syndrome of dispersal with 40 (56.3%) and 71 (55.5%) wind-dispersed species in Chamela and Chajul, respectively. Zoochory was significantly associated with inconspicuous flowers and anemochory with conspicuous flowers. Our results suggest that (1) flower morphology and dispersal type are not related with the amount of rainfall and (2) lianas are more prone to be wind-dispersed