Polish Botanical Journal 58(2): 625–627, 2013 DOI: 10.2478/pbj-2013-0067 A new species of Cleistes (orchidAceAe, VAnilloideAe) from colombiA Marta KolanowsKa 1 & Dariusz l. szlachetKo Abstract. Cleistes cuatrecasasii Kolan. & Szlach. sp. nov. from the Pacifc slope of the Colombian Andes is described and illustrated. Information about its habitat and distribution is provided, and the taxonomic affnity of the new species is briefy discussed. Key words: Andes, biodiversity, Nariño, taxonomy Marta Kolanowska & Dariusz L. Szlachetko, Department of Plant Taxonomy and Nature Conservation, University of Gdańsk, ul. Wita Stwosza 59, 80-308 Gdańsk, Poland; e-mail: martakolanowska@wp.pl introDuction 1 Corresponding author The Neotropical genus Cleistes Rich. ex Lindl. was described by Lindley (1840) to separate plants characterized by the presence of longitudinal crests or lamellae on the lip, but its species usually have been united within Pogonia Juss. (Schweinfurth 1958; Schultes 1960; Foldats 1970; Williams et al. 1980). Subsequent morphological studies (Dressler & Dodson 1960; Garay 1978; Szlachetko & Rutkowski 2000) and molecular research (Cam- eron 2003) clearly indicated the generic distinc- tiveness of Cleistes. As currently recognized, the genus embraces plants characterized by sessile leaves remotely arranged along the stem. Usually a few showy resupinate fowers are produced per plant. Both sepals and petals are free; the sepals are sub- similar, usually longer but narrower than the petals. The lip is entire or 3-lobed, always or- namented with crests and/or lamellae, with two clavate basal projections. The erect, elongate, slender gynostemium is often ± sigmoid. The column foot is absent. The incumbent, ellipsoid anther is dorsiventrally fattened, motile, and 2-chambered. Four oblong-ovoid to narrowly cylindrical pollinia are produced. Staminodes are wing-like, connate partially with the fla- ment, with the style forming a prominent pocket hiding the basal part of the anther (Szlachetko & Rutkowski 2000). Nowadays over 50 Cleistes species are recog- nized (Christenson 1992; Campacci et al. 2011; Pansarin 2004; Pansarin & Barros 2008; Szla- chetko & Baranow 2012). The geographical range of the genus extends from Peru to Costa Rica, with the highest diversity observed in Brazil (Carnevali & Ramírez-Morillo 2003). The only species known from North America (southeastern USA) is C. di- varicata (L.) Ames. Plants of the genus prefer open areas such as savannas, rocky outcrops or bogs, and they are often found growing in moist, well-drained, sandy, acid soils (Cameron 2003; Carnevali & Ramírez- Morillo 2003). The occurrence of ca 13 Cleistes species has been reported from Colombia, most of them found in lowland and lower montane areas up to 2000 m a.s.l. (Ortiz Valdivieso & Uribe Vélez 2007; Szla- chetko & Baranow 2012). Our recent studies on the orchid flora of southern Colombia revealed the existence of a distinctive Cleistes species which is described here as new.