Memecylon nervosum Vadhyar, J.H.F.Benj. & Sujana, a new species of Melastomataceae from the Kanyakumari Wildlife Sanctuary, Western Ghats, India, is described and illustrated. It is compared with the closely allied Memecylon heyneanum Benth. and Memecylon jambosioides Wight.

Leaf anatomical and carbon isotope ratio (δ13C) data from previous studies suggest that the species of the Melastomataceae perform C3 photosynthesis and that leaf anatomical features of some epiphytic taxa resemble the characteristics found in CAM plants. The δ13C values of 67 species of neotropical Melastomataceae (including epiphytes) were obtained from herbarium material deposited at the California Academy of Sciences for assessing the presence of the CAM pathway. The δ13C values obtained from leaves (−23.4‰ to −34.5‰) were congruent with C3 photosynthesis (< −20‰), and the δ13C data from terrestrial (56 samples) and epiphytic species (11 samples) were not statistically different. Our results suggest that CAM photosynthesis is not found in neotropical Melastomataceae. The leaf anatomical features found in some species of Melastomataceae represent adaptations to cope with water stress and are not necessarily correlated with CAM photosynthesis. Photosynthetic pathways can be assessed with the use of leaf anatomical and δ13C data, but further biochemical assays are warranted to corroborate the absence of the CAM pathway in the Melastomataceae.

Coexistence of closely related species is a central issue in community ecology, and those species are expected to present niche differentiation, particularly when resources become scarce (García & Arroyo 2005). Hence, resource abundance and diet differences might be playing a key role in determining species coexistence (Chapman & Rosenberg 1991, Stevenson et al. 2000). Trophic niche differentiation in frugivorous birds could be driven by fruit selection, morphology, behaviour (Moermond & Denslow 1983, 1985) and the spatiotemporal resource dynamics (Blake & Loiselle 1991, Saracco et al. 2005, Solórzano et al. 2000).

Tigridiopalma magnifica, a perennial herb and the only species in the genus Tigridiopalma (Family Melastomataceae) is rare and endemic to China where it is categorized as Critically Endangered on the national Red List. Twelve locations with populations of T. magnifica have been identified (1 extinct, 11 extant). T. magnifica only grows in the surface soil on stone walls or rocks under the canopy of secondary forests and plantations and has no specific associated plant species. Canopy closure, soil water content and the distance to the closest stream are the main factors influencing the distribution of T. magnifica. We reintroduced T. magnifica plantlets produced by tissue culture into three locations: one within the species' original range, and 11.5 and 400 km from the species' original range. After 11 months survival rate was 40–58% but survival was higher and plantlet crowns were larger at the location within the species' original range than at the other two sites. The combination of advanced propagation techniques and ecological restoration could facilitate reintroduction and conservation of T. magnifica and other rare and threatened plants. This example of the successful reintroduction of a rare, threatened herb has implications for human-assisted migration and colonization of rare plant species under future climate change scenarios.

Similarities and differences among eight upland rain forest sites in Peruvian Amazonia were measured separately by using Melastomataceae, pteridophyte and tree species compositions and edaphic characteristics of the sites. All three plant groups showed a similar pattern among the sites, and this pattern could be explained by edaphic differences but not by geographical distances among the sites. The explicability of site-specific edaphic characteristics on the basis of geological history is discussed. The results suggest that both pteridophytes and Melastomataceae can be used as indicators of floristically different rain forest types that are edaphically defined. Distribution patterns of these plant groups can be studied much more rapidly than the patterns of trees and therefore both Melastomataceae and pteridophytes may be used in large scale phytogeographical studies that are urgently needed in the face of rapidly advancing deforestation.

An examination of living material of Bredia (Melastomataceae) in Taiwan and a comparison with herbarium material of the genus from eastern Asia (China, Japan and Taiwan) has led to the recognition of two new species, B. dulanica C.L.Yeh, S.W.Chung & T.C.Hsu and B. laisherana C.L.Yeh & C.R.Yeh. The morphology and diagnostic characters of these two species are described and illustrated and a key to the species of Bredia in Taiwan is given.

Studies in western Amazonian forests have found that similarities in soil cation concentration and texture explain floristic similarities between sites, when these are measured using trees, pteridophytes or Melastomataceae. However, it is not known to what extent the three plant groups react to the same soil characteristics, because tree studies have almost always been conducted in different areas than studies on the understorey plant groups. We made inventories in 23 sites representing non-inundated rain forests on clayey to loamy soil in three regions of western Amazonia. Significant Mantel correlations between the floristic patterns of trees and pteridophytes were found in all three regions when floristic differences were measured with species presence–absence data. When species abundance data were used, and when the floristic patterns of trees and Melastomataceae were compared, significant correlations were found in one or two regions. Mantel correlations between plant groups were highest in the two regions where the observed variation in soil characteristics was largest. In all regions, the same soil variables emerged with significant Mantel correlations with trees, pteridophytes and Melastomataceae. Soil calcium and magnesium were most frequently retained in the models of multiple regression on distance matrices. On average, soil differences explained 50% of the variation in floristic differences (range = 14–84%), and geographical distances explained 16% (range = 0–64%). Our results demonstrate that beta diversities of the three plant groups are highly correlated, and that much of this congruence is explained by similar reactions to soil variation. These results support the idea that pteridophytes, and to a lesser degree Melastomataceae, can be used as indicators of general floristic and edaphic patterns in Amazonian rain forests. Since understorey plants are much quicker to inventory than trees, this would make it possible to recognize and map floristic patterns over huge areas of lowland Amazonia within a reasonable time.

Plethiandra (Melastomataceae–Melastomatoideae–Dissochaeteae) comprises seven species in Borneo and one (P. sessiliflora) in the southern part of Peninsular Malaysia and central Sumatra. Plethiandra is easily recognized by its polystaminate androecium, having 16–40 stamens with short, straight, inappendiculate anthers. The closely related Medinilla has a diplostemonous androecium with 8–12 stamens and variously appendaged anthers. Ontogenetic studies in P. hookeri show that the increase in stamen number in Plethiandra results from subdivision of the stamen primordia into three or more subprimordia.

This paper provides a key, genus and species descriptions including diagnostic characters, distribution maps and ecological notes. One species, P. tomentosa, is newly described. During field observations on P. hookeri and P. cuneata pollination by bees and dispersal by birds and squirrels were observed.

Beetles of the family Cerambycidae can girdle stems and larvae bore live or dead stems of their host plants (Linsley 1961), and when they use active tissues (e.g. xylem), can affect the development and survivorship of their hosts (Nowak et al. 2001). Moreover, borer attack can rapidly stress host plants (Matter 2001), often killing them (Nowak et al. 2001). Consequently, they can cause changes in size structure of the plant population, depending on the intensity of attack and plant survival rates (Caraglio et al. 2001). Cerambycids of the genus Oncideres (Lamiinae) present the most specialized behaviour in host-plant use, in which the female cuts stems with its mandibles and prepares the oviposition site above the cut portion by perforating the bark and then inserting eggs (Caraglio et al. 2001, Rice 1989, 1995).

The Amazonian rain forests form one of the largest areas of continuous forest in the world, and they harbour a substantial part of the world's biodiversity (World Conservation Monitoring Centre 1992). The extravagant species richness of Amazonia makes collecting information on species distribution patterns there a formidable challenge. Relatively few studies have been able to provide data that cover both a large enough number of species and wide enough geographical areas to allow relevant biogeographical and ecological generalizations (such studies concerning plants include Balslev 1988, de Oliveira & Daly 1999, Pitman et al. 1999, Prance 1973, ter Steege et al. 2000, Terborgh & Andresen 1998, Tuomisto & Poulsen 1996). The scarcity of field observations is undoubtedly one of the reasons why very different ideas exist about the mechanisms that control plant distributions and patterns of species richness in Amazonia (Balslev 1988, Condit 1996, Gentry 1988, Nelson et al 1990, Pitman et al. 1999, Prance 1973, 1982; ter Steege et al. 2000, Tuomisto et al. 1995).

This study addresses the pollination ecology of shrub species in an upper montane forest in Costa Rica, where the diversity of insect visitors is much below that of the well-studied tropical forests of lower elevations. Data are presented on visitation rates by the tropical bumblebee Bombus ephippiatus to flowers of three species, pollen loads on bumblebee bodies, and pollen loads on stigmas of two of the species. High visitation rates to flowers of Palicourea brenesii were found, a species which produces copious amounts of nectar. Visitation rates to nectarless Leandra subseriata and Deppea grandiflora were much lower. Conspecific pollen comprised on average 90% of the pollen load on stigmas of Leandra, while Palicourea stigmas carried only 26 to 55% conspecific pollen. With only two ovules per flower, fruit and seed set in Palicourea were not limited by a shortage of conspecific pollen. In Leandra, 20–25% of the flowers received too few conspecific pollen grains for maximum seed set among 440 ovules per flower. Individual bumblebees showed no constancy in plant choice, judging from the high number of different pollen types (6–12) on their bodies. Workers returned frequently to the same Palicourea patch without visiting nearby Palicourea plants, which suggests the use of foraging paths.