Macrosamanea macrocalyx (Ducke, 1922) Barneby & J. W. Grimes, Mem., 1996

Esilva, Wanderson Luisda Silva, Batistasoares, Marcosvinicius, Morim, Marli Pires, Iganci, João Ricardo Vieira & Santos, João Ubiratan Moreira Dos, 2015, Rediscovery of Macrosamanea macrocalyx (Leguminosae: Mimosoideae), a threatened endemic species from the Middle Xingu River, Amazonia, Brazil, Phytotaxa 224 (3), pp. 276-282 : 277

Rediscovery of Macrosamanea macrocalyx

Macrosamanea macrocalyx was rediscovered during field expeditions that covered an area of about 30 km ² along the Middle Xingu River and included Ambé, Altamira, Panelas and smaller igarapés (creeks) along the Xingu and Arapujá Island.

The only population of M. macrocalyx found comprises around 20 flowering and fruiting individuals along Ambé igarapé, near the Trans-Amazon Highway (BR 230) in an area of about 6,000 m ², on clay soil (03° 11’ 44”S, 052° 12’ 32”W). The population consists of scattered individuals about 100–150 m distant from each other. No seedlings were observed in the area.

Herbarium samples of Macrosamanea were examined in the following collections: BM, F, IAN, INPA, K, MFS, MG, MO, NY, P, RB, R, S, U and US (acronyms according to Thiers, continuously updated). We also examined the herbarium teaching collection of the Universidade Federal do Pará (ATM, polo Altamira—Middle Xingu flora collection) and digital images available in the INCT-Virtual Herbarium of Flora and Fungi (http://inct.splink.org.br/). The 11 samples of M. macrocalyx located came from only two field collections, by A. Ducke (16622) in 1916, and by J.G. Kuhlmann (2035) in 1924, in the same area where we found the species.