Taxonomic novelties in Mikania ( Asteraceae : Eupatorieae ) from Atlantic Forest , Brazil

During studies of Brazilian Atlantic Forest Asteraceae, a new species and a replacement name were determined: Mikania amorimii from Bahia State and Mikania capixaba from Espirito Santo State. The former is a new species related to M. ternata but distinct by its leaves, involucral bracts and cypsela morphology. The latter is proposed as a replacement name for Mikania dentata G.M.Barroso, a later homonym of M. dentata Spreng. Line drawings and comments about conservation status are made for both species.

The Atlantic Forest is one of the major hotspots, harbouring almost 4 % of the world's flora -c.20 000 of 420 000 estimated plant species (Myers et al. 2000, Govaerts 2001, 2003).Of these, nearly 40 % are endemic to this biome -c. 8 000 (Myers et al. 2000, Da Fonseca et al. 2005).In the same way, the Atlantic Forest is home to 910 Asteraceae and 122 Mikania species (Stehmann et al. 2009) representing an important centre of diversity and endemism of the genus (Holmes 1995).
Etymology -The species is named after André M. Amorim, our friend, curator of CEPEC herbarium and collector of the type material.
Conservation -Mikania amorimii is represented only by the holotype, collected in one of three Atlantic Forest fragments in southern Bahia, place where 15 species of Mikania are presently registered (A.Amorim pers.comm.).Although these places present high levels of species richness and endemism (Amorim et al. 2005, Thomas et al. 1998), more information is needed to evaluate the true conservation status of the new species.According to previous recommendations of IUCN (2001), the new species is categorized under DD category.Borges & Fraga, Mikania dentata G.M. Barroso, Arch. Jard. Bot. Rio de Janeiro 16 (1959) 275, f.V-m, non Mikania dentata Spreng.( 1826 Notes - Barroso (1959) described 17 new taxa in her revision.Of these, Mikania barrosoana G.M.Barroso, M. hoffmaniana G.M.Barroso, M. pseudohoffmaniana G.M.Barroso and M. pseudohoffmaniana var.macrophylla G.M. Barroso were invalidly published (Art. 7.11,37.1,37.2 and 37.5).All were later validated by Holmes (1993).In the same publication, the species Mikania dentata G.M.Barroso was described with an illustration of the leaf.However, the name is a later homonym (Art.53.1) of M. dentata Spreng., which is a synonym of Calea pinnatifida (R.Br.)Less (Holmes 2001, Ritter & Miotto 2005).Barroso's use of the name M. dentata is therefore illegitimate (King & Robinson 1987).In preparing the Espírito Santo State List of Threatened Plant Species (Fraga et al. 2007), critical study of the type material of M. dentata G.M.Barroso confirmed that it represents a distinctive species, that needed to be validly published.

Mikania capixaba
Etymology -The replacement name makes reference to the known geographic distribution of the species.The specific epithet is a name of indigenous origin meaning fertile land, and generally used in allusion of people born in Espírito Santo.The use of 'capixaba' is supported by the Code's Article 23.2.(McNeill et al. 2006).
Conservation -The species was not mentioned in the Brazilian Red List of Endangered Plants (Mello-Filho et al. 1992).However, it was categorized by Kollmann et al. (2007) -under the name M. dentata G.M.Barroso -as a vulnerable species (VU) in the Threatened Plant Species Regional List of the Espírito Santo State.For the moment, following the Brazilian conservation context, the species is better classified under DD category.