Roupala

Abstract: Proteaceae are restricted to the Southern Hemisphere, and of the seven tribes of the subfamily Grevilleoideae, only three (Macadamieae, Oriteae, and Embothrieae) have living members in Argentina. Megafossil genera of Proteaceae recorded from Patagonia includeLomatia, Embothrium, Orites, andRoupala. In this report, we evaluate and revise fossil Argentine Proteaceae on the basis of type material and new specimens. The new collections come from the Tufolitas Laguna del Hunco (early Eocene, Chubut Province), the Ventana (middle Eocene, Rio Negro Province), and the Rio Nirihuau (late Oligocene-early Miocene, Rio Negro Province) formations, Patagonia, Argentina. We confirm the presence ofLomatia preferruginea Berry,L. occidentalis (Berry) Frenguelli,L. patagonica Frenguelli,Roupala patagonica Durango de Cabrera et Romero, andOrites bivascularis Romero, Dibbern et Gandolfo. Fossils assigned toEmbothrium precoccineum Berry andE. pregrandiflorum Berry are doubtful, and new material is necessary to confirm the presence of this genus in the fossil record of Patagonia. A putative new fossil species of Proteaceae is presented as Proteaceae gen. et sp. indet. Fossil Proteaceae are compared with modern genera, and an identification key for the fossil leaf species is presented. Doubtful historical records of Proteaceae fossils for the Antarctic Peninsula region and Patagonia are also discussed. Based on this revision, the three tribes of Proteaceae found today in Argentina were already present in Patagonia by the early Eocene, where they probably arrived via the Australia-Antarctica-South America connection.

Abstract: The upper montane forests are known to have a different floristic composition and phytosociological structure from forests located at lower altitudes. A survey was carried out in an area of upper montane forest of the Mantiqueira Range near Monte Verde, municipality of Camanducaia, Minas Gerais State, Brazil. The main objective of this study was to analyze the effect of an altitudinal gradient on the floristic composition and vegetation structure. Seven blocks, each with five of 10 × 10 m plots, were located at altitudes ranging from 1,820 m to 1,940 m, and all bamboos and trees with GHB >15 cm were sampled. A total of 1,191 individuals were included, belong to 64 tree species and two bamboos in a total of 42 genera and 26 families, including the standing dead individuals. The estimated density was 3,403 ind ha-1 and the value of the Shannon-Wiener (H') index was 3.284 nat ind-1. The dead biomass had the highest importance value (42.06), followed by Pimenta pseudocaryophyllus (Gomes) Landrum (24.59), Roupala rhombifolia Mart. ex Meisn. (19.98) and Drimys brasiliensis Miers (18.57). The structural parameters maximum canopy height and number of branched individuals were correlated with altitude. Although the altitudinal gradient is relatively short, a considerable degree of species substitution was observed, leading to a well-marked floristic gradient.

Abstract: The American Proteaceae are outliers from the main centres of diversity of the family in Australia and South Africa. There are about 83 species in eight genera which all belong to the monophyletic subfamily Grevilleoideae. Three genera, Embothrium, Oreocallis and Lomatia, are placed in the tribe Embothrieae (sensu Johnson and Briggs), four Euplassa, Gevuina, Panopsis and Roupala in the Macadamieae and the single genus Orites in the Oriteae. There are five genera endemic to America and three also have species in Australia and New Guinea (Gevuina, Lomatia and Orites). The Proteaceae appear to have arrived in South America via two routes. The larger genera Euplassa, Panopsis and Roupala, which are all endemic to America and have a general distribution in northern South America and south-eastern Brazil, are derived from Gondwanaland before it separated from South America. The remaining genera are distributed either in temperate South America or in the high Andes and appear to have arrived more recently via the Australia–Antarctica–South American connection. Three of these genera have species in both regions. The centres of species diversity of Euplassa, Panopsis and Roupala fall outside hypothesised forest refugia, indicating that they are not true rainforest species but species of seasonal habitats like those achieved at higher altitudes where they are commonly found. Two genera,Panopsis and Roupala, have reached Central America after the central American land bridge was formed six million years ago. The exact relationship to genera on other continents is still unclear and there is a need for a cladistic biogeographic analysis of the group based on both morphological and molecular data.

Abstract: The physiognomy and structure of the tree component of a montane forest fragment located in an area at 900 m altitude (8o11'144" -8o12'27" S and 36o23'730" -36o24'638" W), with 948 mm of annual rainfall, and deep soil were studied. All alive or dead standing plants with diameter at breast height > 5 cm, within 50 contiguous plots, 10 x 20 m each, had their trunk diameter, total plant height and canopy projection area measured. The species were classified in relation to their leaf size, deciduousness, and lamina composition. A total of 61 species were sampled plus one unidentified taxon. Plant density, basal area and average and maximum height and diameters were 1,553 plant ha-1, 39 m2 ha-1, 10.3 and 30 m, 14.2 and 105 cm, respectively. About 75% of all alive plants had between 1.4 and 3 m high. The distribution of basal and canopy areas according to height class indicated two ranges of plant concentrations: 7-13 and 19-22 m. The forest fragment represents a transition between humid and dry montane forests. Most of the species are evergreen with simple microphyllous leaves (Casearia sylvestris Sw., Guapira nitida (Schmidt) Lundell, Marlierea clausseniana (O. Berg) Kiaersk., Ocotea aff. elegans Mez, Plinia sp.), they occurred in the canopy of the forest, together with notophyllous species (Amaioua cf. guianensis Aubl. and Roupala paulensis Sleumer) and mesophyllous (Fabaceae sp. and Inga marginata Willd.). The emergent trees are mostly deciduous and compound leaf species, such as Copaifera trapezifolia Hayne and Eriotheca crenulaticalyx A. Robyns.