Gomesa

Abstract: Anthropogenic disturbances have resulted in an increased threat of extinction of many native orchid taxa in Brazil's Atlantic rain forest. In nature, orchids utilize mycorrhizal fungi to initiate seed germination and seedling development, at least in the early stages of their life cycle. Mycorrhizal fungi associated with the roots of orchids have thus been isolated, characterized and stored as important resources for a future conservation program of orchid species through symbiotic seed germination. Three mycorrhizal Rhizoctonia-like fungi were isolated from roots of three neotropical orchid species Gomesa crispa, Campylocentrum organense and Bulbophyllum sp. from three different Atlantic rain forest fragments in Brazil. Taxonomic studies based on the nuclear condition, vegetative hyphal morphology and septal pore ultrastructure revealed that the isolates belong to the genera Ceratorhiza and Rhizoctonia. This is the first report on the isolation of mycorrhizal fungal species associated to the referred neotropical orchid species. Aspects concerning their taxonomy and use in the context of a native orchid conservation programs are discussed.

Abstract: The Orchidaceae species that occur in Prainha Municipal Natural Park are presented. The Park is located in Rio de Janeiro Municipality and has126 hectares. Park vegetation is mainly Atlantic Rain Forest, with a small portion of sandy coastal plain vegetation and several rocky outcrops. Eighteen genera and 26 species of Orchidaceae were found in the area: Bifrenaria (1 sp.), Brassavola (1 sp.), Catasetum (1 sp.), Cattleya (2 sp.), Cyclopogon (1 sp.), Cyrtopodium (2 sp.), Eltroplectris (1 sp.), Epidendrum (4 sp.), Gomesa (1 sp.), Isochilus (1 sp.), Maxillaria (2 sp.), Oeceoclades (1 sp.), Oncidium (1 sp.), Pleurothallis (3 sp.), Polystachya (1 sp.), Prescottia (1 sp.), Sarcoglottis (1 sp.) and Sophronitis (1 sp.). Several species are widely distributed geographically, but 14 occur only in the Atlantic Rain Forest domain. A species key, descriptions, illustrations, and comments on life form, flowering and fruiting, geographic distributions and habitats are included.

Abstract: This study reports the floristic survey of Orchidaceae occurring in 125 forest fragments distributed among 23counties of the central region of Sao Paulo state, Brazil. In this region, the family is characterized by 219species distributed in 96 genera. Individuals collected in the vegetative state were maintained in a greenhouseuntil flowering. The majority of species (64%) are epiphytes, while 35% are terrestrial, 14.6% are rupicolous,two (0.9%) are hemi-epiphytes and one is mycoheterotrophic (0.4%). Acianthera (13 spp.), Habenaria andGomesa (12 spp.), and Epidendrum (11 spp.) are the most representative genera. Of the unidentified species,four are possibly new to science: Anathallis sp., Baskervilla sp., Pelexia sp., Triphora sp. Furthermore, a newcombination for the genus Gomesa R.Br. is presented. The central portion of Sao Paulo state is an ecotonebetween Brazilian Savanna and Atlantic Forest with a high number of species from both formations. Manyspecies (44.7%) are rare in the study area and are threatened due to anthropogenic disturbance and indiscriminatecollecting of orchids.Key words: Savanna, ecotone, Atlantic Forest, floristic survey.