George John Shepherd

Distribution and abundance of arboreal species in the atlantic ombrophilous dense forest in Southeastern Brazil

The relative densities of arboreal species of 17 surveys carried out in the Atlantic Ombrophilous Dense Forest of São Paulo state, SE Brazil, were compared by means of multivariate analysis (cluster, TWINSPAN, PCA, DCA and CCA) to assess floristic and structural variation. The arboreal flora of this vegetation formation is heterogeneous: out of the 771 specific binomials cited, 478 were recorded only once. As the results were similar whether these 478 species were included or not, they were therefore excluded from subsequent analyses. The cluster analysis and TWINSPAN recognised two floristic-structural groups: Coastal Province and Atlantic Plateau. The DCA resulted in a gradient related to distance from the sea, from the Coastal Province towards the Atlantic Plateau (λ1=0.6944). The CCA confirmed this separation on the first axis (λ1=0.6944; 12.7% of total variance; p<0.01) and showed this gradient to be associated with altitude and latitude on one hand and temperature and precipitation on the other. The influence of latitude and longitude was weak. Although surveys used different criteria, only the minimum individual size adopted in sampling showed a weak influence on the second axis on the CCA (λ2=0.4437; 8% of total variance), and sampling method showed no influence. A positive relationship between geographical distance and floristic-structural dissimilarity was detected by the Mantel test (Zobs=0.320; Zave=0.300; p<0.001). The predominance of arboreal species of restricted distribution and the great spatial variation of abundance would appear to indicate narrow niches. The occurrence of complex and non-linear gradients suggests the importance of several other abiotic features in the spatial distribution and abundance of arboreal species in the Atlantic Ombrophilous Dense Forest in the state of São Paulo.

Studies on the reproductive biology ofMelastomataceae in “cerrado” vegetation

Controlled pollinations and observations of pollen tube growth, pollen fertility and cytological data were studied in 11 species ofMelastomataceae growing in “cerrado” in SE Brazil. Seven species produced apomictic fruits with viable seeds. Four species were not apomictic, with two self-incompatible (gametophytic SI) and two self-compatible, one showing spontaneous self-pollination. The apomictic species had lower pollen fertility than sexual ones — although in some cases differences were not significant — showing that low pollen fertility may be a useful indicator of apomixis if analysed using careful sampling supplemented by emasculation experiments. The apomictic species also showed meiotic irregularities, probably related to hybridization, polyploidy and the cause of low pollen fertility. Apomixis in this group probably is more associated with taxonomy and phylogeny than habitat or habit, since 85% of the apomictic species reported in the literature belong to the tribeMiconieae and occur in a wide range of vegetation types and have diverse habits. This suggests the existence of very extensive apomictic complexes comparable to those reported in mainly temperate genera ofAsteraceae andRosaceae.

Floristic comparison of mesophytic semideciduous forests of the interior of the state of São Paulo, Southeast Brazil

The floristic composition (trees) of 26 forests in the state of São Paulo, Brazil, was compared using cluster analysis and Principal Coordinates Analysis (PCO) with simple Euclidean distance. The results obtained indicate the existence of two floristically distinct groups of forests. One group contains forests from higher areas (above 700 m) with a colder climate (Cfa and Cfb) and includes surveys from Angatuba, Atibaia, Guarulhos, Jundiaí, São José dos Compos and São Paulo. The second group is floristically less homogeneous and includes forests of the central and western parts of the state, usually at lower altitudes (500–700 m) and subject to hotter climatic conditions (Cwa).

Floristic Composition and Community Structure of a Central Brazilian Gallery Forest

Summary An intensive study was made of a gallery forest near Cuiaba, State of Mato Grosso. Analysis of the vegetation on 67 plots of 30 m 2 demonstrated a great deal of heterogeneity related principally to differences in topography and drainage. Four distinct communities were recognized: dry cerradao, wet cerradao, wet forest and swampy forest. Comparison of an informal site classification based on field observations, showed a very high degree of coincidence with ordination and a hierarchical classification based on analysis of floristic, topographic and soil data from plots. A total of 89 species with individuals ≥3 cm basal diameter were recorded. Soil data for the plots are also presented.

The ecological and taxonomic importance of flower volatiles of Clusia species (Guttiferae).

The chemical composition of floral volatiles of sixteen species of Clusia (Guttiferae) belonging to four different taxonomic sections of the genus was investigated. The volatiles were extracted from fresh petals by microhydrodistillation and analysed by GC/MS. The composition of the volatiles was in part, but not always, related to the taxonomic position of the species, and to a minor extent to the type of pollinator observed on the flowers as revealed by clustering analysis. The composition of the volatile components of female and male flowers belonging to the same species (C. grandiflora, C. lanceolata, C. paralicola, C. parviflora and C. spiritu-sanctensis) was found to be almost identical. Field bioassays showed the petal extracts to be attractive to pollinating bees.

Floristic Composition and Community Structure in an Area of Cerrado in SE Brazil

Summary Cerrado is the generic name for the savanna-like vegetation which occupies the vast area of the central Brazilian plateau and also extends into peripheral, fragmented islands within the Surrounding moist forests. Cerrado occurs as a complex of intergrading structural sub-types which range from more or less closed forest to open grassland with scattercd shrubs, and it also shows phytogeographical shifts in floristic composition although these are as yet poorly studied. This investigation presents for the first time a full list of the woody species from one of the peripheral islands of cerrado in Sao Paulo state. In addition, a principal components analysis of the data from 60 quadrats of 10 × 25 m indicates that the two community subtypes present in this area, cerrado and campo cerrado , distinguished by Goodland on the basis of physiognomic characteristics, can also be defined in terms of species composition. The possible causes for these floristic and physiognomic sub-communities are examined but no single controlling factor can be established.

Clerodane-type diterpenes from the seed pods of Hymenaea courbaril var. stilbocarpa

Three known and two new diterpenes were isolated from the ethyl acetate extract of Hymenaea courbaril var. stilbocarpa seed pods. One of the compounds was elucidated as (5R*,8S*,9S*,10R*)-cleroda-3,13E-dien-15-oic acid and the other was elucidated, after treatment with diazomethane, as methyl (5S*,8S*,9S*,10R*)-cleroda-3,13E-dien-15-oate. The known diterpenes were identified as (-)-ozic acid, (-)-isoozic acid and (-)-kovalenic acid which were characterized as their methyl ester derivatives.

Análise temporal da heterogeneidade florística e estrutural em uma floresta ribeirinha

Floristic composition and phytosociological structure were studied in a fragment of riverine semideciduous forest, along Passa Cinco River, Ipeuna, Sao Paulo State, southeastern Brazil. A total of 157 continuous plots (5 x 10 m) totalising 0.785 ha were sampled. All trees ³ 5 cm DBH were measured and mapped in 1989 and 1998. The presence of a vegetacional mosaic was observed and possible factors determining this heterogeneity are discussed. Multivariate analysis of vegetation revealed the presence of three vegetacional groups, indicating a strong relationship with edaphic features in the area. Quantitative analysis of community structure showed differences among these groups, which have not changed over time, reinforcing the correlation with soil cover. Vegetational type above alluvial soil, at river banks, showed strong floristic differences, greater diversity, basal area and density. After nine years, few changes occurred in the phytosociological structure for the most important species in the area, with an increase of 2.01% in the total density and 2.80% in total basal area.

Reproductive systems and crossing potential in three species of Bulbophyllum (Orchidaceae) occurring in Brazilian 'campo rupestre' vegetation

Experimental self-, cross- and interspecific pollinations were carried out inBulbophyllum weddellii, B. involutum andB. ipanemense (Orchidaceae). The last two species are closely related, butB. weddellii is somewhat more distant. The three species are self-compatible, with pollination by a vector necessary for fruit formation. In all crossing types, high rates of fruit abortion and formation of seeds without embryos were observed, particularly in interspecific crosses that involvedB. weddellii. Crosses between the more closely relatedB. involutum andB. ipanemense produced fruit formation rates and seed viability similar to those obtained in intraspecific crosses. These results agree with current hypotheses that suggest that interspecific crossing rates reflect phylogenetic proximity. Examination of pollen tube growth and aborted fruits suggests that a series of factors may be involved in the high abortion rate for fruits and large proportion of seeds without embryos. The low interspecific fertility noted forB. weddellii andB. involutum is important in the maintenance of isolation between these species that are sympatric, flower in the same period and share the same pollinators.

Checklist das Spermatophyta do Estado de São Paulo, Brasil

The Phanerogamic Flora of Sao Paulo State project has been dedicated to create an inventory of the flora for 20 years. More than 200 collaborators are involved, mostly from the State of Sao Paulo, with the contributions of researchers from other states and from abroad. Since 2001, seven books with monographs of 151 families were published, dealing with 3,237 species within 722 genera. This project was the starting-point of the gathering of information about the diversity of spermatophytes of the State of Sao Paulo. The current checklist, at this point, presents an updated and virtually complete list of species, all certified by specialists. It also contains references to scientific collections for most of the taxa (vouchers) or to bibliography referring to the natural or subspontaneous occurrence of the species in the State. The list now contains 7,305 species distributed in 1,776 genera and in 197 spermatophyte families (according to Cronquist 1981) or 195 (according to APG III). 23% of the 31,728 species of spermatophytes listed in the Flora of Brazil occur in Sao Paulo State. The most representative families are Orchidaceae (797 species), Asteraceae (676 species), Fabaceae (513 species), Poaceae (500 species), Myrtaceae (304), Rubiaceae (265 species) and Melastomataceae (253 species), which, altogether, accumulate 3,308 species and constitute 45% of total species of spermatophytes in the state. The wealth of the Brazilian plant diversity, partially expressed in Sao Paulo, shows how important is the continuity of floristic studies in a country that is very likely to hold the largest plant diversity in the planet.