The Araceae in Ceará, Brazil: humid forest plants in a semi-arid region

Publication Type:Journal Article
Year of Publication:2013
Authors:de Andrade, I. Moreira, Mayo, S. Joseph, Silva, M. Francilene, de Sousa, D. José Lima, Matias, L. Queiroz, Ribeiro T. Alves
Journal:Rodriguesia; Revista do Instituto de Biologia Vegetal, Jardim Botanico e Estaçao Biologica do Itatiaya
Start Page:445
Keywords:florestas serranas, floristics, Geocat, Monocotyledons, semiarid region

The study consists of a taxonomic treatment of the Araceae of Ceará, a state lying within Brazil’s semi-arid region. The aroid flora shows greater similarity to those of central Brazil and Amazonia than to the Atlantic forest. Most species occur in humid forest fragments - the “florestas serranas”. Geophytes are also found in caatinga and dry forest (Taccarum ulei) and lithophytes on rock outcrops in dry forest (Philodendron acutatum). Floating aquatics occur in ponds and lakes throughout the state (Pistia stratiotes, Lemna aequinoctialis, Lemna minuta, Spirodela intermedia, Wolffia columbiana, Wolffiella welwitschii), and freshwater helophytes (Montrichardia linifera) along river margins. 28 taxa (species and varieties) in 19 genera are described and most are illustrated: Anthurium (three spp.), Caladium (one sp.), Dieffenbachia (one sp.), Dracontium (one sp.), Lemna (two spp.), Monstera (two spp., one with two varieties), Montrichardia (one sp.), Philodendron (four spp.), Pistia (one sp.), Scaphispatha (one sp.), Spathicarpa (one sp.), Spathiphyllum (one sp.), Spirodela (one sp.), Syngonium (one sp.), Taccarum (one sp.), Wolffia (one sp.), Wolffiella (one sp.), Xanthosoma (two spp.), Zomicarpa (one sp.). New records for Ceará are Dieffenbachia aglaonematifolia, Dracontium nivosum, Monstera adansonii var. laniata, Philodendron sp. aff. ruthianum and the naturalized exotic Typhonium roxburghii. An identification key and data on geographic distribution and conservation status are provided.

Full Text

The family Araceae Juss. currently consists of 126 genera and 3305 species (Boyce & Croat 2012). It is sub-cosmopolitan in distribution and most species and genera occur in the tropics (Mayo et al. 1997). The family is very diverse in life form, morphology and anatomy (Grayum 1990), ranging from massive arborescent or epiphytic herbs to minute floating aquatics (Bogner 1987; Croat 1990; Mayo et al. 1997). The duckweeds, formerly known as Lemnaceae S.F. Gray, are now subfamily Lemnoideae, a near-basal clade within Araceae (Cabrera et al. 2008; Cusimano et al. 2011). Armstrong (2012) is an excellent illustrated reference for duckweeds. The Araceae form the basal clade in the order Alismatales (Stevens 2001 onwards; APGIII 2009). Braga’s (1960) checklist, based on information from Ceará, includes many cultivated taxa and remains a useful source although the nomenclature is often out of date. Coelho et al. (2010, 2012) is currently the most complete checklist for Brazil. Andrade et al. (2006) published a checklist for Brazil’s semi-arid region. Papers dealing with one or several species, mostly reports of new discoveries or records, have been published by Gonçalves & Temponi (2004) and Bogner (1980). Population genetics and biogeography of Anthurium Schott and Monstera Adans. in the upland humid forests of Ceará have been studied by Andrade et al. (2007, 2009), who also studied leaf morphometrics in the same taxa (Andrade & Mayo 2010; Andrade et al. 2008, 2010). Some Ceará species are included in more general revisions: Philodendron Schott: Sakuragui et al. (2006); Scaphispatha Brongn. ex Schott: Gonçalves (2005); tribe Spathicarpeae: Gonçalves (2002); Spathiphyllum Schott: Bunting (1960); Syngonium Schott: Croat (1981) and Zomicarpa Schott: Gonçalves (2012).

The state of Ceará lies within the semi-arid region of Northeast Brazil and is almost entirely covered with caatinga vegetation, a deciduous thorn forest (Figueiredo 1997). During the rainy season, temporary lakes and ponds with aquatic species are found throughout the landscape. Montane forests (“brejo forests”) occur naturally where higher rainfall is caused by suitable combinations of humid winds, altitude, scarps and position (usually facing to the east and northeast). These areas are classified as remnants of formerly more extensive areas of Brazilian Atlantic Forest (Figueiredo 1997: “Floresta subperenifolia tropical pluvionebular”). Higher rainfall and lower temperatures allow the development of large evergreen trees and epiphytic and hemi-epiphytic flora in uplands on granitic geology at Baturité, Maranguape, Meruoca, Uruburetama, Pacatuba, and along the leading edge and scarp of sedimentary outcrops in northern Ibiapaba and the Chapada do Araripe (Oliveira & Araújo 2007).
The aim of this study is to provide the first published taxonomic treatment for the State of Ceará of the family Araceae, plants which in this mostly semi-arid region are confined largely to relictual humid montane forest fragments (Andrade & Mayo 2010).

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith