Orchidaceae da Reserva Particular do Patrimônio Natural Parque do Zizo, Tapiraí, São Paulo, Brasil

Abstract

Orchidaceae is one of the two largest families of flowering plants in the world, with 28,000 species distributed across 736 genera, divided into five subfamilies: Apostasioideae Horan., Vanilloideae Kostel, Cypripedioideae Lindl. ex Endl., Orchidoideae A.A.Eaton, and Epidendroideae Szlach. In Brazil, there are approximately 2,683 species. Considering the scarcity of detailed taxonomic studies of the family in the Atlantic Forest and its high diversity and taxonomic complexity, the objective of this study is to prepare a checklist of the Orchidaceae species occurring in the Reserva Particular do Patrimônio Natural (RPPN) Parque do Zizo, one of the remaining areas of Dense Ombrophilous Forest in the state of São Paulo. The RPPN Parque do Zizo is located on the top of the Serra Paranapiacaba, in the southern region of the state of São Paulo, between the municipalities of São Miguel Arcanjo and Tapiraí, covering approximately 9,000 ha. The survey included the following steps: consulting the literature, field data collection through 15 expeditions, and analysis of specimens in herbaria. A total of 89 Orchidaceae species were recorded in the RPPN Parque do Zizo, belonging to 36 genera, namely: Acianthera (3 spp.), Anathallis (2 spp.), Barbosella (2 spp.), Bifrenaria (2 spp.), Bulbophyllum (1 sp.), Campylocentrum (2 spp.), Cattleya (2 spp.), Cirrhaea (1 sp.), Cleistes (1 sp.), Cyclopogon (1 sp.), Dichaea (2 spp.), Elleanthus (1 sp.), Encyclia (1 sp.), Epidendrum (8 spp.), Eurystyles (1 sp.), Gomesa (9 spp.), Grobya (1 sp.), Isochilus (1 sp.), Lankesterella (1 sp.), Maxillaria (8 spp.), Mesadenella (1 sp.), Microchilus (3 spp.), Octomeria (5 spp.), Pabstiella (9 spp.), Pelexia (1 sp.), Phymatidium (2 spp.), Polystachya (1 sp.), Promenaea (2 spp.), Prosthechea (3 spp.), Scaphyglottis (1 sp.), Specklinia (1 sp.), Stelis (5 spp.), Warrea (1 sp.), Xylobium (1 sp.), Zygopetalum (3 spp.), Zootrophium (1 sp.). These species are distributed across three subfamilies (Epidendroideae, Orchidoideae, and Vanilloideae), with the majority being epiphytic (94%), and the remaining being terrestrial (6%). Of the 89 Orchidaceae species sampled, 50 species are endemic to Brazil, with 47 species exclusive to the Atlantic Forest biome. Five species found in the area are listed as endangered. Gomesa albinoi is reported as a new occurrence for the state of São Paulo. Microchilus caraguatatubensis is the only species sampled that is endemic to São Paulo, and was first recorded outside its type locality (municipality of Caraguatatuba), contributing to the knowledge of the taxonomic diversity of Orchidaceae in Brazil. An identification key for the species, with photographic records of those occurring in RPPN Parque do Zizo, based on diagnostic characters, is provided. Seven families were sampled as forophytes and substrates of Orchidaceae in the area, with the most representative family being Myrtaceae, which had 6 species.