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1 Phytotaxa 218 (1): ISSN (print edition) Copyright 2015 Magnolia Press Article PHYTOTAXA ISSN (online edition) A taxonomic synopsis of the Mexican species of Acianthera (Orchidaceae: Pleurothallidinae) including a new species RODOLFO SOLANO GOMEZ Instituto Politécnico Nacional, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional Unidad Oaxaca, Hornos 1003, Santa Cruz Xoxocotlan, CP 71230, Oaxaca, México; solanogo@yahoo.com.mx Abstract Acianthera pollardiana is herein described as a new species based on specimens collected in Oaxaca, Mexico. Information concerning the distribution, habitat, phenology and conservation status for this taxon is provided. In addition, traits that distinguish this species from similar taxa are mentioned, and a line drawing, photograph, and a map of known localities are also shown. A taxonomic synopsis of Mexican Acianthera in which twenty species are accepted is also provided. Acianthera herrerae, whose presence has only previously been recorded in Guatemala, is here reported for first time for the Mexican flora. Acianthera javieri, A. markii, and A. martinezii are placed under the synonymy of A. angustisepala, A. tikalensis, and A. hondurensis, respectively. Moreover, an artificial key for Acianthera species is included in this synopsis and maps of known localities in Mexico are presented. Resumen Acianthera pollardiana es descrita aquí como nueva especie con base en especímenes colectados en Oaxaca, México. Se proporciona información referente a la distribución, hábitat, fenología y estatus de conservación para este taxón. Además se señalan los rasgos que distinguen esta especie de taxa similares, también se presenta un dibujo a línea, fotografía y un mapa de localidades conocidas. También se proporciona una sinopsis taxonómica para Acianthera mexicanas en la cual veinte especies son aceptadas. Acianthera herrerae, cuya presencia solo había sido registrada previamente en Guatemala, es reportada aquí por primera vez para la flora mexicana. Acianthera javieri, A. markii y A. martinezii son colocados bajo la sinonímia de A. angustisepala, A. tikalensis y A. hondurensis, respectivamente. Por otra parte, en la sinopsis se incluye una clave artificial para la especies de Acianthera y se presentan mapas de las localidades conocidas en México. Key words: Acianthera pollardiana, Mexico, orchids, taxonomy Introduction Acianthera Scheidweiler (1842: 292) is a genus comprising approximately 210 species within Pleurothallidinae, the largest orchid subtribe in number of species (Pridgeon & Chase 2001, Pridgeon et al. 2005, Chiron & van den Berg 2012). Members of Acianthera typically grow as epiphytes, lithophytes, or rarely as terrestrials in cloudy, wet or dry forests from Mexico to Uruguay and Northern Argentina, including the Antilles. This genus is richest in Brazil, where almost 120 species have been registered (Barros et al. 2010). Acianthera has long been included as a synonym of the broadly circumscribed Pleurothallis Brown in Aiton (1813: 211) in most taxonomic treatments and floras of Orchidaceae in Neotropical countries. At the end of the 20 th century, this group was treated at a subgeneric level as Pleurothallis subgen. Acianthera (Scheidw.) Luer (1986: 12). However, at the beginning of the 21 st century, a phylogenetic study of Pleurothallidinae, based on DNA sequences, provided strong support for the recognition of Acianthera as a different group within the subtribe (Pridgeon et al. 2001; Chiron & van den Berg 2012). Consequently, this group is currently recognized at the generic level. In Mexico, 18 species of Acianthera have been identified (Soto et al. 2007), six of which are endemic. An additional species, A. herrerae (Luer 1991: 100) Solano & Soto Arenas (2003: x), was discovered in Guatemala, and this taxon has only recently been found in Mexico. Taxonomic treatments are available for 14 Mexican Acianthera (Hágsater & Accepted by Cássio van den Berg: 4 Jun. 2015; published: 30 Jun

2 Soto 2003; Solano 2010), and treatments for three additional species are underway. Specimens belonging to another undescribed taxon were also collected several years ago in the state of Oaxaca in Southern Mexico. Although the name Acianthera pollardiana (Soto et al. 2007) has been previously mentioned in the literature, this name has not been formally published. Thus, herein, we provide the first formal description of this species. A taxonomic synopsis, an artificial key, and a map of all known localities for Mexican Acianthera are provided herein. The synopsis and the key presented herein could also be used to classify taxa in northern Central America (Belize, Guatemala, and El Salvador). Materials and methods The description of the new species was based on specimens cultivated at the orchid collections of AMO Herbarium and La Encantada (Octavio Suárez, Oaxaca, Mexico). For the line drawing, a complete specimen was drawn using a camera lucida, while fresh and dissected flowers were measured and drawn on a stereoscopic microscope (Wild Heerbrugg Type ) coupled with a drawing tube. For the taxonomic synopsis, type information was acquired from type specimens and protologues of the original descriptions. In the case of old publications (18 th, 19 th and the first half of the 20 th century), the protologues were accessible from Biodiversity Heritage Library ( The type specimens were observed from Mexican herbaria (AMO, MEXU, OAX) and online photos available through JSTOR Global Plants ( plants.jstor.org), Field Museum of Natural History (F, Lankester Botanical Garden, University of Costa Rica (CR, Missouri Botanical Garden (MO, Muséum National d Histoire Naturelle (P, The Natural History Museum (BM, Naturhistorisches Museum Wien (W, botany), Oak Ames Orchid Herbarium (AMES, Royal Botanical Gardens (K, kew.org/collections/herbcol.html), Smithsonian Institution (US, botany.si.edu/), and the Swedish Museum of Natural History (S, For each Mexican Acianthera species, information concerning the nomenclature (correct and synonyms names, cites of the original publications, and type references), general distribution within Mexico, and specimens with documented presence in the country was provided. In some cases, when the species type was not designated in the original publication or when this has been destroyed, it was necessary to select and designate a lectotype or neotype. The localities for Mexican Acianthera were obtained from the revision of collections deposited in AMO, ENCB, FCME, FEZA, HEM, IEB, MEXU, OAX, UAMIZ, XAL, XALU herbaria, and through online databases from the AMES, BM, F, K, MO, P, US, and W herbaria. The localities for all Acianthera records were georeferenced, when the available information facilitated this process, and superimposed onto a map of Mexico using ArcGIS 10.2 software (ESRI, 2012). It is necessary to justify here the use of the term stem to designate the more or less vertical axis carrying leaves and flowers in the Pleurothallidinae subtribe, instead of ramicaul as proposed by Stern & Pridgeon (1984). Ramicaul is defined as a branch of the cauline, stem or axial system in sympodial orchids, but this term has also been used to describe other orchid groups. Reeves & Reeves (1984) applied this term to describe the Malaxis scape. The term secondary stem was previously employed to designate the caulinar axis in Pleurothallidinae and the primary stem to the rhizome, which is completely erroneous, as all stems on the plant are secondary structures. However, caulome was proposed prior to ramicaul to designate the caulinar axis bearing leaves, branches and reproductive structures (Oxford English Dictionary, thus, both terms could generate equivalent results. In other groups of sympodial monocots, the term rhizome is used to designate the horizontal part of the plant bearing roots, while the stem is used to describe the usually erect axis carrying leaves and flowers, regardless of whether this structure is thickened or not (Rasmussen 1985, 1986, Andersen et al. 1988, Soto 1987). As a result, it would be considered inappropriate to use ramicaul, as this structure is not a branch and is not branched. Thus, herein, the caulinar axis of Pleurothallidinae will simply be referred to as a stem according to Rasmussen (1985) and Soto (1987), as there is no possibility of confusing this term with any other plant structure, such as rhizome, peduncle, or pedicel. 40 Phytotaxa 218 (1) 2015 Magnolia Press SOLANO GOMEZ

3 Figure 1. Acianthera pollardiana Solano & Soto Arenas. A. Habit. B. Abscision zone between stem and leaf with the inflorescence. C. Floral dissection. D. Ovary, lip and column, lateral view. E. Lip, ventral view. F. Column, ventral view. G. Anther. H. Pollinarium. Drawn by R. Solano based on specimen cultivated without locality data. A taxonomic synopsis of Acianthera Phytotaxa 218 (1) 2015 Magnolia Press 41

4 Taxonomic treatment Acianthera pollardiana Solano sp. nov. (Figs. 1 2, 5) Similar to Acianthera chrysantha (Lindley 1859: 14) Pridgeon & Chase (2001: 243), from which is distinguished by their broader leaves, tubular and nearly closed flowers, and fleshy, more lanceolate, five-veined sepals. Type: MEXICO. Oaxaca: Distrito Tlaxiaco, Municipio Santiago Yosondúa, paraje La Cueva del ex Presidente, localidad de Cascada la Esmeralda, 1913 m, 16º N, 97º O, bosque de galeria, 7 October 2014, D. Sandoval 1248 & A. Sandoval (holotype MEXU!). Figure 2. Acianthera pollardiana, photo by G. Salazar, based on Sandoval & Sandoval Epiphyte, erect, short cespitous herb, up to 25 cm tall. Roots flexuous, whitish, ca. 1 mm in diameter. Rhizome short, globose, comprising three internodes. Stem unifoliate, as long as or longer than the leaf, straight or slightly arching, progressively dilated and winged toward the apex, cm long, ca. 4 mm wide, 8.6 mm thick, comprising two internodes, the proximal shorter than the distal, the distal one conduplicate, covered by tubular, scarious, shedding sheaths. Leaf sessile, fleshy, elliptic to ovate-elliptic, obtuse-rounded, shortly bilobed at apex and with a minute mucro between lobes, cm. Inflorescence arising from the apex of the stem, racemose, up to 3 cm long; peduncle terete, 7 mm long, 1.2 mm diameter, enclosed by a conduplicate, obtuse, scarious bract, 8 9 mm long, with other two overlapping bracts similar to the floral one, mm long; rachis abbreviated, with 4 6 successively opening and erect flowers in a fan-like arrangement. Floral bracts obliquely funnel-shaped, obtuse, membranous, greenish yellow, 4 5 mm long, overlapping. Flowers with the sepals forming a tube, with a small aperture at apex, mm tall, mm long, 4 5 mm wide; sepals, petals, lip, and column, reddish orange, the anther yellow. Ovary stout, subpyramidal, subtriangular in cross-section, greenish yellow, shortly glandular-pubescent, mm long, articled to a terete pedicel of mm long, both covered by the floral bract. Sepals fleshy, glabrous on the adaxial surface, short glandular-pubescent on the abaxial surface, ciliate, involute along the margins; dorsal sepal united to lateral sepals near its base, elliptic to oblanceolate-spatulate, rounded to obtuse, channeled, subcalyptrate at apex, five-veined, mm; lateral sepals united up to the apex, forming a cymbiform, oval to elliptic, rounded synsepal, shortly retuse at the apex, ten-veined, mm. Petals porrect, fleshy, slightly channeled, obovate to elliptic- 42 Phytotaxa 218 (1) 2015 Magnolia Press SOLANO GOMEZ

5 oblanceolate, rounded, slightly attenuated toward the base, serrulated along upper 3/5, three-veined, mm. Lip fleshy, entire, shortly unguiculate; claw short, membranous, trapezoidal, two-auricled at base; disc slightly arching, conduplicate, oblong-lanceolate, obtuse, shortly apiculate, three-veined, mm, with a pair of submarginal, elevated, thickened calli on the middle third, which descends along the basal margins of the lip. Column slightly arching, ventrally channeled, winged, mm, with a concave foot, 1.9 mm long; wings oblong, 0.4 mm tall, slightly erose along the margins, clinandrium projecting, covering the anther, concave, denticulate; stigmatic cavity ventral, subquadrate, viscous; rostellum galeate, ventral. Anther ventral, ovoid, incompletely divided inside by a pair of septa, mm long; pollinarium mm long, comprising two ovoid, laterally compressed, yellow pollinia, attached to two granulose, flake-like caudicles. Capsule not seen. Distribution and habitat: Endemic, known only from the Sierra Madre del Sur of Oaxaca (Fig. 5). This species grows between 2,000 and 2,200 m in elevation, in pine-oak or ravine mesophytic fores, with Taxodium mucronatum Tenore (1853: 355), Quercus magnoliifolia Née (1801: 268), Q. pubescens Willdenow (1796: 279), Fraxinus uhdei (Wenzig 1883: 182) Lingelsheim (1907: 221), Gliricidia ehrenbergii (Schlechtendal 1838: 303) Rydberg (1924: 239), Litsea glaucescens Kunth (1817:168), and Randia cookii Standley (1934: 176), which are surrounded by pine forests at higher sites. The plant is an epiphyte on oak trees like Quercus magnoliifolia. Phenology: Flowering from September to October. Etymology: The specific name honors the memory of Glenn E. Pollard, who lived in Oaxaca City in the 1960s and 1970s studying Mexican orchids. Additional specimens: MEXICO: Oaxaca: Municipality of Santiago Yosondua, Mixteca region, m, secondary vegetation derived from the oak forest, collected June 2001, pressed September 2004, Suárez 2273 (OAX); municipality of Santa Catarina Juquila, road Juquila to Ixpantepec, 29 September 2005, Solano 1297 (OAX); unknown locality, prepared from cultivated specimen at AMO, October 2000 (AMO); unknown locality, Lau s.n. (AMO [photo]). Comments: Among the Mexican Acianthera, this species is easily recognized according to its stout habit, orange-reddish, elongated and more or less tubular flowers, and its fleshy, five-veined sepals. This species is similar and occasionally sympatric with another Mexican endemic taxon, A. chrysantha, but it can be recognized according to its smaller habit, narrower leaves, shorter bilabiate and more open flowers. The Mesoamerican A. circumplexa (Lindley1838: 24) Pridgeon & Chase (2001: 243) is also similar, but can be distinguished by prominent abaxially keeled leaves, raceme apparently arising from the foliar blade, and shorter, bilabiate flowers. Although the South American A. aurantiolateritia (Spegazzini 1916: 132) Pridgeon & Chase (2001: 242) has similar flowers, this plant has lanceolate, narrow leaves, raceme longer than the leaf, several flowers that simultaneously open, and aristate petals. Acianthera pollardiana is endemic to the Sierra Madre del Sur of Oaxaca, a little explored region with other geographically restricted orchid species whose range extends to the mountains surrounding the Central Valleys of Oaxaca, highlighting the importance of this region as a priority biological conservation area (Salazar & García-Mendoza 2009, Salazar et al. 2010, Solano 2010). The geographically restricted orchids in this region include Cypripedium molle Lindl. in Bentham (1840: 72), Dichromanthus cinnabarinus subsp. galeottianum Soto Arenas & Salazar in Hágsater & Soto (2003: xii), D. yucundaa Salazar & García-Mendoza (2009: 24), Galeoglossum cactorum Salazar & Chavez-Rendon in Salazar et al. (2011: 262), Habenaria subauriculata Robinson & Greenman (1896: 34), Laelia furfuracea Lindley (1839: 26), and Stelis sotoarenasii Solano (2010: 450). Conservation status: Not evaluated by the IUCN Red List or the Method of Extinction Risk Evaluation for Mexican wild flora and fauna species. This plant is scarcely known and has been collected from few localities, where the populations have seemingly low densities and in some parts of its range the forest is perturbed by itinerant agriculture. However, there is still suitable habitat for this species in unexplored areas in Southern Oaxaca. Taxonomic synopsis of Mexican Acianthera 1. Acianthera angustifolia (Lindl.) Luer (2007: 118). Pleurothallis angustifolia Lindley (1836a: 7 sub Tab. 1797). Type: MEXICO. Veracruz: Prope Xalapa, , Schiede & Deppe s.n. (holotype K, isotypes BR[82681]! W!). Pleurothallis carioi Schlechter (1918a: 205). Type: Guatemala. Chilion prope Mazatenango, August 1866, Bernoulli & Cario 496 (holotype B ; because this specimen was destroyed during World War II, it is necessary to designate here the following specimen as neotype: GUATEMALA. Chichou f. Majato, 17 August 1867, Bernoulli & Cario 458, K[583978]! [Fig. 8]). A taxonomic synopsis of Acianthera Phytotaxa 218 (1) 2015 Magnolia Press 43

6 Figure 3. Map showing the known Mexican localities for Acianthera angustifolia, A. angustisepala, A. breedlovei, A. chrysantha and A. circumplexa. Distribution: Mexico (Tamaulipas, San Luis Potosi, Veracruz, Oaxaca, Chiapas [Fig. 3]), Guatemala, Belize, Honduras, and Nicaragua. Specimens: MEXICO. Tamaulipas: Aldama, Rancho Las Yucas, Los Cerritos a Sierra La Borrada, 23 July 1957, Dressler 1961 (MO!); Gómez Farías, Reserva de la biosfera El Cielo, LaCaille s.n. (AMO!); Jaumave, 13 June 1932, Rozynski sub Oestlund 669 (AMES!); Llera, 4 km al N Ejido La Libertad, 200 m, N, 30 April 1983, Valiente et al. 522 (MEXU!). Veracruz: Coatepec, Ejido Tuzumapan Chavarrillo, 850 m, 7 September 1979, Castillo & Tapia 851 (F!); Emiliano Zapata, Rancho Viejo Palmarejo, 620 m, Morales 24 (XALU!); Emiliano Zapata, La Laja, entre Corral Falso y Pinoltepec, 835 m, Sousa & Delgado 4847, 4558 (MEXU!); Huatusco, Paraje El Angostillo, 500 m, 9 April 2000; Salazar et al (MEXU!); Jilotepec, La Concepción, 950 m, 13 February 1978, Ventura (AMO); Naolinco, Almolonga, 600 m, 17 September 1976, Ventura (AMO!); Tepetzintla, La Regua, cerro Otontepec, 700 m, 29 July 1981, Castillo & Benavides 2353 (F!); Xalapa, ca. Xalapa, 28 October 1830, Deppe 52 (AMES!), Xalapa, 28 October 1830, Schiede & Deppe 55 (W!); Zacuapan, November 1906, Purpus 2122 (AMES!); Zacuapan, February 1932, Nagel sub Oestlund 2658, 4688, 4777 (AMES); Dos Ríos, Corral Falso, 700 m, 22 November 1965, Ventura 7441 (ENCB!). Oaxaca: Totontepec Villa de Morelos, 2 km antes de Amatepec, 1900 m, 16 September 1991, Jiménez 1132 (AMO!); Totontepec Villa de Morelos, Amatepec, 1900 m, 16 September 1991, Jiménez & Suárez 2191 (AMO!). Chiapas: Berriozábal, 1 km N entronque aeropuertos sobre carretetera Ocozocoautla-México, 940 m, 3 March 1988, Reyes & Sousa 414 (MEXU!); Ocosingo, El Real, 25 August 1954, Dressler 1781 (AMES!); Ocosingo, 6 8 km N of Ocosingo road to Bachajon, 900, m, 9 November 1971, Breedloe & Smith (CAS! MEXU!); Ocosingo, 22 km al NO de Ocosingo, 1200 m, 3 August 1984, Espejo et al (MEXU! UAMIZ!); Ocozocoautla de Espinosa, 21 km W Tuxtla Gutiérrez camino a Ocozocoautla, 1,030 m, 31 May 1987, Martínez & Soto (MEXU!); Ocozocoautla de Espinosa, 7 km N Ocozocoautla a Malpaso, 560 m, Martínez (MEXU!); Ocozocoautla de Espinosa, km 5 Ocozocoautla-Apicpac, 850 m, Pimentel 81 (MEXU! UAMIZ!); Palenque, 500 m sobre desviación a Yajalón a partir del camino Palenque-Ocosingo, 950 m, Espejo 4646 (UAMIZ!). Notes: Acianthera wilsonii (Lindley 1858: 326) Pridgeon & Chase (2001: 16) is a phenetically similar species from the Caribbean basin (Colombia, Venezuela, and the Antilles), and is considered as a different species here, following Stenzel (2004). 44 Phytotaxa 218 (1) 2015 Magnolia Press SOLANO GOMEZ

7 2. Acianthera angustisepala (Ames & Correll) Pridgeon & Chase (2001: 242). Pleurothallis angustisepala Ames & Correll (1942: 74). Holotype: GUATEMALA. Department Alta Verapaz: above Tamahú, alt ,200 m, 5 April 1939, Standley (F[995124]!). Acianthera javieri Archila (2009: 14) syn. nov. Holotype: GUATEMALA: Department of Alta Verapaz, Coban, Tontem Village, 1,400 m, collected in 2000, Archila FA-071 (BIGU[37296]). Distribution: Mexico (Chiapas [Fig. 3]), Guatemala, and Belize. Specimens: MEXICO. Chiapas: Ocosingo, Laguna Ocotal Grande, 20 July 1954, Dressler 1543 (AMES! MEXU!); Oxchuc, 20 km SW Ocosingo camino a San Cristóbal de las Casas, 1,320 m, 13 October 1986, Martinez et al A (MEXU!), (CAS! MEXU!); Rayón, 500 m abajo de Rayón, 1,340 m, 10 April 1989, Soto & Martinez 4919 (AMO!). Notes: Acianthera javieri is only known from the type collected in Guatemala; the description and illustration provided by Archila (2009) does not facilitate discrimination from A. angustisepala; the different traits that the author described are part of the variation previously described and illustrated for this species (Ames & Correll 1942, Hágsater & Soto Arenas 2003, Luer 2004). 3. Acianthera breedlovei Soto Arenas, Solano & Salazar in Hágsater & Soto (2003: 502). Holotype: MEXICO. Chiapas: ca. 100 km SW of Palenque on Hwy 199, near Tunapaz, 31 August 1986, Catling & Brownell M18.3 (AMO[6312]!). Distribution: Mexico (Chiapas [Fig. 3]), Honduras, Nicaragua Costa Rica, and Panama. Specimens: MEXICO. Chiapas: 950 m, 23 September 1988, Breedlove (CAS!); Ocosingo, 22 km al N de Ocosingo, 1,200 m, 3 August 1984, Espejo et al (UAMIZ!); Ocozocoautla de Espinosa, Laguna Bélgica, Moreno s.n. (HEM!); Ocozocoautla de Espinosa, 900 m, 17 August 1972, Breedlove (CAS!); Ocozocoautla de Espinosa, 600 m, 27 August 1972, Breedlove (CAS!);Ocozocoautla de Espinosa, 850 m, 10 August 1990, Cabrera 133 (CAS!); Ocozocoautla de Espinosa, km 192 carretera Cosoleacaque, 25 August 2001, Martínez 472 (HEM!); Ocozocoautla de Espinosa, 14 km Ocozocoautla to Malpaso, 1,030 m, 13 July 1972, Pollard 1A a (MEXU!); San Fernando, 950 m, 14 July 1981, Breedlove (CAS!). Notes: Acianthera breedlovei is member of a group of closely related species that include A. pubescens (Lindley 1836b: 355) Pridgeon & Chase (2001: 245) and A. majakoluckae Soto Arenas & Solano in Hágsater & Soto (2003: 510), and other widespread Neotropical taxa. See notes on A. pubescens. 4. Acianthera chrysantha (Lindl.) Pridgeon & M.W.Chase (2001: 243). Pleurothallis chrysantha Lindley (1859: 14), replacement name for Pleurothallis aurea Richard & Galeotti (1845: 16) nom. illeg., not Lindley (1843: 397); Humboltia chrysantha (Lindl.) Kuntze (1891: 667). Holotype: MEXICO. Cordillera Oaxaca, Mexico, 8,000 ft., November 1840, Galeotti 5009 (W[12704]!). Distribution: Mexico (Guerrero, Oaxaca [Fig. 3]). Specimens: MEXICO. Guerrero: Chilpancingo de los Bravo, 1.6 km de Omiltemi a Amojileca, 2,100 m, 5 November 1999, López-Ferrari et al (UAMIZ!); General Heliodoro Castillo 10 km SW de Carrizalillo camino a Puerto de El Gallo, 2,600 m, Martínez 3919 (MEXU!). Oaxaca: San Juan Mixtepec, 10 km SW de San Juan Mixtepec, 2,500 m, 5 January 1988, Reyes 1415 (MEXU!); San Lorenzo Albarradas, al N de la barranca de San Lorenzo, 1,900 m, 6 April 1934, Nagel sub Oestlund 3796 (AMES!); San Pedro El Alto, Pacific near San Pedro El Alto, 31 August 1936, Nagel sub Oestlund 5322 (AMES! AMO! MO!); San Vicente Lachixio, km 21 de El Vado al Aserradero El Tlacuache, 2,224 m, 20 November 2014, Solano 4226 (OAX!); Santa Cruz Itundujia, La Era, 10 October 2007, Velasco 2375 (MEXU!); Santa María Ecatepec, entre San Juan Acaltepec y Santo Tomás Teipan, 2,100 m, 12 December 1991, Soto et al s.n. (AMO!); Santo Domingo Albarradas, 5 km camino Santa María Albarradas a Santo Domingo Albarradas, 1,900 m, 8 February 1987, Soto & Greenwood 3132, 3133 (AMO!); Santo Domingo Albarradas, ca. 8 km Santa María a Santo Domingo Albarradas, 2,151 m, 28 July 2011, Solano 4024 (OAX!); Santiago Yasondúa, Imperio, 2,230 m, 4 April 2006, M. Mendoza 208 (MEXU!); Santiago Yasondúa, 2,287 m, 13 November 2006, Mendoza 632 (MEXU!); Santiago Yosondúa, paraje El Molino, 2,393 m, 13 November 2006, M. Mendoza 643 (MEXU!); Santiago Yasondua, paraje Yucuntusu, 2,289 m, 13 November 2006, Mendoza 654 (MEXU!); Santos Reyes Nopala, ca. 11 km delante de Los Reyes sobre carretera Oaxaca-Villa Sola de Vega-Juquila, 2,100 m, 1 August 1993, Espejo & López-Ferrari 624, A taxonomic synopsis of Acianthera Phytotaxa 218 (1) 2015 Magnolia Press 45

8 625 (AMO!); Villa Sola de Vega, microondas Sola de Vega, carretera Oaxaca-Puerto Escondido, 2,200 m, 14 March 2012, Solano 4072 (OAX!). 5. Acianthera circumplexa (Lindl.) Pridgeon & Chase (2001: 243). Pleurothallis circumplexa Lindley (1838: 24); Humboltia circumplexa (Lindl.) Kuntze (1891: 667). Holotype: MEXICO. from Mexico by Messrs. Loddiges, with whom it flowered in February, 1838, Loddiges s.n. (K, with analysis!). Pleurothallis mesophylla Richard & Galeotti (1845: 16). Type: MEXICO. Oaxaca: 8,000 f, 1840, Galeotti 5026 (lectotype [designed by Soto Arenas In Hágsater & Soto 2003: 504] P[485699]! isolectotypes G[168960]! W!). Distribution: Mexico (Guerrero, Oaxaca, Hidalgo, Puebla, Veracruz, Chiapas [Fig. 3]), Guatemala, El Salvador, Nicaragua and Costa Rica. Specimens: MEXICO. Veracruz: Naolinco, región of Xalapa near Almolonga, 800 m, 1 Aprol 1935, Nagel sub Oestlund 4857 (AMES! MEXU!); Orizaba, 12 March 1866, Bourgeau 2472 (K!); Totutla, El Mirador, Liebmann 7304 (C! W!); Totutla, Zacuapan, 26 April 1932, Nagel sub Oestlund 2548 (AMES!); San Andres Tuxtla, volcán San Martín, 3 January 1938, Nagel sub Oestlund 5770 (AMES!); San Andrés Tuxtla, ejido Barrio Lerdo, falda del volcán San Martín, 1,500 m, 14 May 2005, Krömer 2224 (MEXU!); Yecuatla, delante de Paz de Enríquez, 1,520 m, 9 December 1966, Gómez-Pompa 1805 (MEXU!). Oaxaca: Pluma Hidalgo, 1,400 m, 1 January 1936, Nagel sub Oestlund 5313 (AMES!); San José Chiltepec, La Joya del Obispo, 370 m, Ramos & Martínez 688 (MEXU!); San Miguel del Puerto, Cerro Lobo, 1,728 m, 27 March 2006, Vásquez 84 (MEXU!); San Pedro Nolasco, Sierra de San Pedro Nolasco, Jurgensen 946 (AMES!); Santa María Chimalapa, cañada de la Hierba Santa, subiendo al Cerro Guayabitos, 1,270 m, 25 October 1996, Salazar et al (AMO!). Chiapas: Ángel Albino Corzo, Reserva de la Biosfera El Triunfo, zona núcleo I, 5 September 2005, Reyes 67 (HEM); Coapilla, above Coapilla road to Pantepec, 1,980 m, 21 October 1988, Breedlove (CAS, MEXU!); Coapilla, carretera Coapilla-Tapalapa, 20 September 2006, Martínez-Melendez 1513 (HEM); Jilotol, 5 km después de Bochil, 1,820 m, 27 May 1995, Wolf 2419 (MEXU!); Motozintla, 13 km W-SW de Motozintla camino El Porvenir, 1950 m, 27 February 1988, Martinez (MEXU!); Motozintla, SW of cerro Motozal, 2,460 m, 21 November 1976, Breedlove (MEXU!); Ocosingo, 1,065 m, 15 January 1982, Breedlove (CAS!); Ocozocoautla de Espinosa, Zona Sujeta a Conservación Ecológica Laguna Bélgica, N, W, Moreno s.n. (HEM); Pueblo Nuevo Solistahuacán, entre Bochil y Pichuclaco, 1,400 m, 1 February 1979, Croat (AMES!); Siltepec, La Lucha, Reserva de la Biosfera El Triunfo, 1,740 m, 21 July 2005, Reyes 55 (HEM). 6. Acianthera eximia (L.O.Williams) Solano in Hágsater & Soto (2003: 505). Pleurothallis eximia Williams (1942: 166); Acianthera eximia (L.O.Williams) Luer (2004: 253) superfluous. Type: MEXICO. Oaxaca: On trees in humid forests, Pacific slopes, Valley of Copalita River NW of Pluma Hidalgo, 1,000 m, 1936, flowered 4 March 1937, Nagel & Gonzalez 6067 (holotype AMES[74246]! isotypes F[46433F]! MEXU[540507]! MO! S[7001]! SEL[767]! US[439253]!). Distribution: Mexico (Oaxaca [Fig. 4]). Specimens: MEXICO. Oaxaca: Candelaria Loxicha, Santiago La Galera, 9 km al N de La Galera carretera a Miahuatlán, 1,450 m, 23 February 1988, Campos & Reyes 1448 (AMO!); Pluma Hidalgo, valley of river Coapalita, NW of Pluma Hidalgo, 1,000 m, 2 March 1937, Nagel & González sub Oestlund 6067 (AMES! AMO!); San Jerónimo Coatlán, 26.7 km al SW de San Jerónimo brecha a Piedra Larga, 1,700 m, 2 December 1990, Campos 3505 (MEXU!); Santa Catarina Juquila, 168 km de la carretera Oaxaca-Puerto Escondido, 1,920 m, 21 November 1992, Jiménez et al (AMO!); Santiago Textitlán, camino a cascada del río Tigre, 1,562 m, 17 August 2006, Nava 1650 (MEXU!); Santiago Xanica, El Placeton, a 1.7 km de Finca El Faro, 1,780 m, 27 November 2004, Velasco et al. 601 (MEXU! SERO!). 7. Acianthera greenwoodii Soto Arenas in Hágsater & Soto (2003: 506). Type: MEXICO. Oaxaca: km 8 del camino entre Santa María Albarradas y San Miguel Albarradas, 2,030 m, 27 November 1992, Soto & Greenwood 7278 (holotype AMO[24120]! isotypes AMES, AMO[24121]! K, MO). Distribution: Mexico (Oaxaca [Fig. 4]). 46 Phytotaxa 218 (1) 2015 Magnolia Press SOLANO GOMEZ

9 Figure 4. Map showing the known Mexican localities for Acianthera eximia, A. greenwoodii, A. hartwegiifolia, A. herrerae and A. hondurensis. Specimens: MEXICO. Oaxaca: Santo Domingo Albarradas, 7 km después de Santa María Albarradas hacia Santo Domingo Albarradas, 1,900 m, 27 November 1992, Soto & Greenwood 3132 (AMO!); San Cristobal de las Casas, 2,133 m, 30 August 1981, Breedlove (CAS!). Notes: This species is phenetically similar to A. chrysantha and A. hartwegiifolia but has abaxially warty sepals instead of a pubescent, spathulate dorsal sepal and less winged stems. 8. Acianthera hartwegiifolia (H.Wendl. & Kraenzl.) Solano & Soto Arenas in Hágsater & Soto (2003: 507). Pleurothallis hartwegiifolia Wendland & Kränzlin (1900: 165). Type: MEXICO. Berge, Blühte in Herrenhausen (Holotype [according to Luer 2004: 24] presumably at B ; because this specimen was destroyed during World War II, it is necessary to designate here as lectotype the Tabula 296. Fig. I II. 1 6 published with the original description [Fig. 9]). Distribution: Mexico (Nayarit, Jalisco, Mexico, Guerrero [Fig. 4]). Specimens: MEXICO. Nayarit: Tepic, laderas hacia el mar del Volcán de San Juan por el camino a El Cuarenteño, 1500 m, 3 May 1986, Soto & Salazar 2381, 2382 (AMO!). Jalisco: Cihuatlán, ca. 1 km antes del aserradero rumbo a La Cumbre, 1,470, 15 June 1988, López-Ferrari et al. 215 (ENCB! FCME!); Talpa, between La Crucecita and El Desmoronado, González-Tamayo s.n. (AMO!); Autlán de Navarro, Sierra de Manantlán, S of El Chante, obove Rincón of Manantlán, McVaugh (AMO!). Michoacán: Patzcuaro, Region de Patzcuaro, 2,000 m, 21 January 1933, Halbinger sub Oestlund 1580 (AMES!); Uruapan, near Uruapan, 1,800 m, 15 November 1905, Pringle (K! LE! M! MEXU! MO! W!); Uruapan, Pedregal de Uruapan, ca. 5 km al SW de San Andrés Coru, 1,800 m, 18 August 1981, Zamudio 8246 (MEXU!); Uruapan, 12 Km al E de Uruapan, sobre la carretera a Pátzcuaro, 1,700 m, 23 January 1977, Rzedowski (ENCB! MEXU!). Mexico: Temascaltepec, Carbonera, 2,000 m, 15 December 1932, Hinton 2796 (AMES! F! K! MO!); Temascaltepec, Carboneras, 1,980 m, 30 March 1933, Hinton 3670 (AMES! K! MO!). Guerrero: Chilpancingo de los Bravo, between San Cristobal & Santa Rosa, 1,600 m, 28 January 1933, Nagel sub Oestlund 4856 (AMES! MEXU!); Chilpancingo de los Bravo, 5 6 km después de Corral de Bravo rumbo a El Paraiso, 2,650 m, 21 March 1981, Espejo et al (UAMIZ!); Eduardo Neri, along highway between Milpillas and Atoyac A taxonomic synopsis of Acianthera Phytotaxa 218 (1) 2015 Magnolia Press 47

10 de Alvarez, 1,325 m, 14 January 1974, Croat (MEXU!); General Heliodoro Castillo, carretera a Filo decaballo cerca de Chilpancingo, 18 January 1983, 2,250 m, Neill & Neil 483 (MO!); General Heliodoro Castillo, 9 km adelante de Corral de Bravo, carretera Filo de Caballo-Puerto El Gallo, 2,540, 25 March 1981, Espejo et al. 57 (FCME!); General Heliodoro Castillo, Corral de Bravo, Márquez s.n. (FCME!); General Heliodoro Castillo, 24 km al S de la Yerbabuena camino a Puerto de El Gallo, 2,230 m, 26 February 1984, Martínez 6188 (K! MEXU!); Malinaltepec, al N de Tres Marías, 2,460 m, 23 November 2005, Lozada 3006 (MEXU!); General Heliodoro Castillo, 24 km al S de la Yerbabuena camino a Puerto de El Gallo, 2,230 m, 26 February 1984, Martínez 6188 (MEXU!); Leonardo Bravo, 10 Km al SW de Carrizalillo camino a Puerto El Gallo, 2600 m, 3 June 1983, Martínez 3919 (MEXU!); Leonardo Bravo, Chichihualco, Asoleadero, ca. km 191 camino Atoyac-Xochipala, 2,500 m, 2 February 1984, Salazar 15 (MEXU!). Notes: This name has been considered a synonym of A. chrysantha (Williams, 1951; McVaugh 1985, Luer 2004) but differs based on stouter and fleshier plants, thicker and more winged stems, and more lanceolate leaves. Acianthera chrysantha also grows in drier forests than A. hartwegiifolia (Soto in Hágsater & Soto 2003: 503). 9. Acianthera herrerae (Luer) Solano & Soto Arenas in Hágsater & Soto (2003: x). Pleurothallis herrerae Luer (1991: 100). Type: GUATEMALA. Prov. of Quetzaltenango, Zunil, alt. 2,100 m, August 1987, Herrera sub Dix & Dix 6522 (holotype MO[149965]! isotype UVAL). Distribution: Mexico (Chiapas [Fig. 4]) and Guatemala. Specimens: MEXICO. Chiapas, región del Volcán Tacaná, Suárez s.n. (photo). Notes: Although this species has not previously been recorded in Mexico, the presence of this species was expected in Chiapas. Here, this species is reported for the first time for Mexican flora. 10. Acianthera hondurensis (Ames) Pridgeon & Chase (2001: 244). Pleurothallis hondurensis Ames (1924: 20). Holotype: HONDURAS. Lacertilla farm near Tela, 350 f, 16 March 1923, Ames II.204 (AMES[74341, with analysis]!). Acianthera martinezii Luer (2005: 311). Pleurothallis martinezii Luer (2004: 46) nom. illeg.; Acianthera martinezii (Luer) Luer (2004: 254) nom. illeg. Holotype: MEXICO. Chiapas: Ocosingo, Estación Chajul, 150 m, 19 Apr. 1993, Martínez & Ramos (AMO!). Distribution: Mexico (Tabasco, Chiapas [Fig. 4]), Guatemala, Belize, Honduras, and Costa Rica. Specimens: MEXICO. Tabasco: Tacotalpa, ejido Zonú, entre Teapa y Tapijulapa, 28 April 1984, Espejo et al. 948 (UAMIZ!); Teapa, Arroyo Mogoshpa, a 3 km del cruce UACH-San Jose Puyacatengo, 185 m, 6 May 1998, Guadarrama (MEXU!). Chiapas: Las Margaritas, 350 m, 11 February 1973, Breedlove (CAS!); Ocosingo, 300 m, 23 February 1973, Breedlove (CAS!); Ocosingo, Maravillas to Tenejapa, confluence of rio Ixcán with rio Lacantún, 160 m, 15 March 1973, Breedlove (MEXU!); Ocosingo, ejido Loma Bonita, 150 m, 14 September 1992, Martínez (MEXU!); Ocosingo, Estación Chajul, 150 m, 20 January 1992, Martínez & Domínguez (AMO! MEXU!); Ocosingo, Estación Biológica Chajul, 150 m, 14 March 1993, Martínez & Ramos (AMO!); Ocosingo, Marqués de Comillas, al N de Estación Biológica Chajul, 160 m, 17 February 199, Sinaca 2320 (MEXU!); Ocosingo, Ribera del Río Lacantún, junto al río Tehuacán, 150 m, 18 February 1999, Sinaca 2327 (MEXU!); Ocosingo, ribera del Río Lacantúm y arroyo Miranda, hacia Estación Biológica Chajul, 150 m, 11 February 1999, Sinaca 2256 (MEXU!); Ocosingo, ribera del río Lacantún, junto al arroyo José desembocadura, 150 m, 17 May 1999, Sinaca & Chankin 2537 (MEXU!); Ocosingo, Marqués de Comillas, circuito La Granja camino al río José, 160 m, 16 March 1999, Sinaca 2409 (MEXU!); Ocosingo, Estación Biológica Chajul, 230 m, 13 April 1997, Soto 8410, 8418, 8435 (AMO!); Ocosingo, Estación Bilógica Chajul, 200 m, 14 April 2000, Soto et al (AMO!). Notes: Apparently, the only difference between A. martinezi and A. hondurensis is the presence of carinae on petals of the former; however, in other aspects, both plants are phenetically indistinguishable, they share ecological affinities and grow in the Yucatan Peninsula biotic province; thus, the two names are considered conspecific. 11. Acianthera johnsonii (Ames) Pridgeon & Chase (2001: 244). Pleurothallis johnsonii Ames (1923: 21). Brenesia johnsonii (Ames) Luer (2004: 255). Type: GUATEMALA. Department Alta Verapaz: Chamá to Cobán, 3,000 ft, 15 August 1920, Johnson 901 (holotype AMES[74369]! isotypes F[867639]! US[ ]). Brenesia costaricensis Schlechter (1923: 200); Pleurothallis lateralis Williams (1956: 84) replacement name for Brenesia costaricensis Schltr., not Pleurothallis costaricensis Rolfe (1917: 80), nor Pleurothallis costaricensis Schlechter 48 Phytotaxa 218 (1) 2015 Magnolia Press SOLANO GOMEZ

11 (1918b: 395) superfluous. Type: COSTA RICA. Bois humides à San Pedro de San Ramón, 1,200 m, September 1921, Brenes 117 (holotype B, photos at AMES[ with analysis]! CR! lectotype AMES[339]! designated by Barringer, 1986: 4). Distribution: Mexico (Chiapas [Fig. 5]), Guatemala, El Salvador, Honduras, Costa Rica and Panama. Specimens: MEXICO. Chiapas: Ocosingo, 30.5 km on road Ocosingo-San Cristobal de las Casas, 2,080 m, 27 October 1977, Greenwood & Brenan 572 (AMO!); San Cristobal de las Casas, Thurston 6241 (AMO!); Oxchuc, carretera Ocosingo-San Cristóbal, entre Ocosingo y Oxchuc, 1,800 m, 26 June 1996, Soto 7984a (AMO!). 12. Acianthera majakoluckae Soto Arenas & Solano in Hágsater & Soto (2003: 510). Holotype: MEXICO Chiapas: Campamento Santiago, km 105 [road mark] San Cristobal de las Casas-Teopisca, ca. 1,400 m, collected June 1976, pressed 11 April 1994, Dressler sub Hágsater 4465 (AMO[17535]!). Figure 5. Map showing the known Mexican localities for Acianthera johnsonii, A. majakoluckae, A. obscura, A. pollardiana and A. pubescens. Distribution: Mexico (Oaxaca and Chiapas [Fig. 5]). Specimens: MEXICO. Oaxaca: Oaxaca de Juárez, montaña de San Felipe, Kennedy 2005 (K! UC!); Santa María Chimalapa, parte alta de la cañada Hierba Santa, subiendo al Cerro Guayabitos, 1,270 m, 25 October 1996, Salazar et al (AMO!). Chiapas: 1,100 m, 19 March 1979, Breedlove (CAS!); 1798 m, 20 March 1979, Durham sub Breedlove (CAS!); Amatenango del Valle, 1 km above Aguacatenango, 1,800 m, 5 June 1988, Breedlove (CAS! MEXU!); Comitán, km 3.2 del camino a Zaragoza de la Montaña, ca. Comitán, 2,000 m, 23 July 1989, Soto & Martinez 5735 (AMO!); Huixtán, camino a Chanal que parte de la carreterea San Cristóbal de las Casas-Ocosingo, 6 February 1989, Soto et al (AMO!); Las Margaritas, km 12.4 camino Las Margaritas-Cruz del Rosario, 1630 m, 23 April 2,000, Soto et al (AMO!); Teopisca, entre Belen y Betania, 2,300 m, 5 May 1987, Espejo 2871 (UAMIZ!); Teopisca, rancho la Cabaña, 1,800 m, Cheme & Lunas 402 (MEXU); Teopisca, km 10 Belém a Teopisca, m, 4 March 1985, Hágsater 4507 (MEXU!). 13. Acianthera obscura (A.Rich. & Galeotti) Pridgeon & Chase (2001: 245). Pleurothallis obscura Richard & Galeotti (1845: 17). Type: MEXICO. Unknown locality: (according to Luer 2004: 51, Richard & Galeotti s.n., holotype P[not located]). A taxonomic synopsis of Acianthera Phytotaxa 218 (1) 2015 Magnolia Press 49

12 Pleurothallis bilamellata Reichenbach (1849: 830). Type: MEXICO. Unknown locality: von Gerold dem Berliner botanischen Garten lebend mitgetheilt (holotype [according to Luer 2004: 51] W[45924]!). Pleurothallis rufa Rolfe (1898: 192). Type: MEXICO. Unknown locality: Flowered in Messrs. Seeger and Tropp s Nursery, East Dulwich, June 1890 (holotype K[584130]! isotype K[584131]!). Distribution: Mexico (San Luis Potosi, Puebla, Veracruz, Chiapas [Fig. 5]). Specimens: MEXICO. Without locality, 1922, Purpus 25 (AMES!). San Luis Potosí: Dino sub Oestlund 5283 (AMES!); Tamasopo, Tamasopo to Cebadilla, 500 m, 25 June 1934, Nagel sub Oestlund 5093a (AMES!). Veracruz: ca. Almolonga, E of Xalapa, 900 m, 5 April 1935, González sub Oestlund 4694 (AMES! MEXU!); ca. Cordoba, Nagel sub Oestlund 4595 (AMES!); Amatlán de los Reyes, ca. de Santa Ana, 750 m, 1993, Solano et al. 602, 603 (AMO!); Coatepec, 15 Km al NE de Coatepec, camino a Jalcomulco, 800 m, 6 November 1973, Cedillo 320 (MEXU); Emiliano Zapata, Rancho Viejo Palmarejo, 620 m, Morales 76 (XALU!); Fortin, 15 February 1982, Luer 6835 (SEL!); Huatusco, paraje El Angostillo, bajando a la barranca desde la Congregación El Pochote, 500 m, 9 April 2000, Salazar 6166 (MEXU!); Totutla, Zacuapan, El Mirador, Porpus 2913 (AMES!); Totutla, Zacupan, Purpus s.n. (BR!); Zentla, km 8.4 camino Manuel González a El Angostillo, Congregación El Pochote, 700 m, 8 April 2000, Soto et al (AMO!). Chiapas: Siltepec, La Lucha, Reserva de la Biosfera El Triunfo, 1740 m, 21 junio 2005, Reyes 46 (HEM!); ca. Piedra Pesada, colindando con Ocozacuantla, 11 April 1947, Moore 2547 (AMES!). Puebla: A. Briones s.n. (photo!). 14. Acianthera pubescens (Lindl.) Pridgeon & Chase (2001: 245). Pleurothallis pubescens Lindley (1836b: 355); Humboltia pubescens (Lindl.) Kuntze (1891: 668). Type: Mexico. Unknown locality, Barker s.n. (holotype K[not located], drawing at AMES[74658]!). Pleurothallis vittata Lindley (1838: 73). Type: MEXICO. Unknown locality. A Mexican species imported by Messrs. Loddiges (holotype K[not located]). Pleurothallis polystachya Richard & Galeotti (1845: 16). Type: MEXICO. Veracruz: unknown locality, 1840, Galeotti 5135 (holotype W, isotype G[168993]!). Pleurothallis mandibularis Kränzlin (1920: 169). Type: MEXICO. Veracruz: Wahrscheinlih aus Mexico stammend, Liebmann s.n. (holotype C, drawing at AMES[74462]!). Pleurothallis bourgeavi Kränzlin (1921: 15). Type: MEXICO. Veracruz: Provinz des tropischen Zentralamerika: Région d Orizala, 17 May 1869, Bourgeau 2469 (holotype P[485787]! isotypes AMES[74092]!! BR[ ]! G[168991]! K[583977]! MPU[18067]! P[485788]! S[6998]!). Distribution: Mexico (Puebla, Veracruz, Oaxaca [Fig. 5]), Guatemala, Belize, Honduras, and Panama; recorded in Venezuela, apparently from plants identified as Pleurothallis truxillensis Reichenbach (1854: 25). Specimens: MEXICO. Puebla: región de Zacapoaxtla, Z. Eslava s.n. (Photo). Veracruz: Trinidad, ca. Córdoba, 15 March 1866, Bourgeau (P!); Orizaba, Bourgeau s.n. (P!); Xalapa, June 1970, Diguet s.n. (P!); Totutla, Zacuapan, Purpus 2142 (AMES!); Purpus 6397 (AMES!); Purpus sub Oestlund 6732 (AMES!); Zacualpan, Viccón s.n. (photo!). Notes: The concept of Acianthera pubescens is somewhat obscure and problematic. Although this name has been applied to species ranging from eastern Mexico to northern Argentina, the country of origin was listed as Mexico. Several phenetically similar taxa have been described from Mexico to South America, but the differences between these species are unclear and these plants have been frequently grouped into the A. pubescens synonymy. Plants from Honduras, Costa Rica, and Panama have narrower leaves, longer stems, and smaller flowers and are herein recognized as a different species, A. breedlovei. However, plants from Chiapas and adjacent Oaxaca, which grow under more xeric conditions at higher elevations and are smaller plants with larger flowers, are considered here as A. majakoluckae. 15. Acianthera sotoana Solano & Soto Arenas in Solano (2010: 447). Type: MEXICO. Oaxaca: Municipio Totontepec Villa de Morelos, cañón del Río Toro, sobre el banco del río, 1,800 m, collected September 1977, pressed 23 July 1983, Suárez sub Hágsater 5536 (holotype AMO[3975]! isotype AMO[3976]!). Distribution: Mexico (Oaxaca, Veracruz, Chiapas [Fig. 6]). Specimens: MEXICO. Oaxaca: Totontepec Villa de Morelos, Santa María Huitepec, Río Llano, 13 March 2009, Solano 2939 (OAX!); Totontepec Villa de Morelos, Rio Toro, 1 January 1980, Suárez 566 (AMO!); Totontepec Villa de Morelos, Rio Toro, 1,900 m, 1 January 1978, Greenwood s.n. (AMO!). Veracruz: Ixhuacán de los Reyes, Comapa, 50 Phytotaxa 218 (1) 2015 Magnolia Press SOLANO GOMEZ

13 1,560 m, 19 October 2008, Viccón & Castañeda 199 (MEXU!); Pajapan, cima del volcan San Marti Pajapan, 1,125 m, 2 August 2007, Kromer & Otto 2954 (MEXU!); Tatahuicapan de Juarez, faldas del Volcan Santa Marta, 1500 m, 28 August 2008, Kromer 3696 (MEXU!). Chiapas: Motozintla, 2,156 m, Damon s.n. (ECOSUR!). Figure 6. Map showing the known Mexican localities for Acianthera sotoana, A. testifolia, A. tikalensis, A. unguicallosa and A. violacea. 16. Acianthera testifolia (Sw.) Solano in Solano et al. (2011: 50). Epidendrum testifolium Swartz (1788: 122). Cymbidium testifolium (Sw.) Swartz (1799: 71). Pleurothallis testifolia (Sw.) Lindley (1858: 328). Humboltia testifolia (Sw.) Kuntze (1891: 668). Apoda-prorepentia testifolia (Sw.) Luer (2004: 255). Type: JAMAICA. Rupens in rupidibus muscosis, truncisque Arborum Jamaicae montosae, Swartz s.n. (lectotype designated by Nir 2000 S[S-R- 1973]! isolectotypes B[16984], BM[82277]! UPS, W[16036]). Cryptophoranthus pectinatus Schlechter (1923: 277). Pleurothallis helleriana Williams (1964: 62) replacement name for Cryptophoranthus pectinatus, not Pleurothallis pectinata Lindley (1839: 29). Type: COSTA RICA. Umgebung von San Ramon, January 1921, Acosta s.n. (holotype B ; destroyed during World War II). Neotype (here designated) illustration and floral analysis based on the holotype at AMES[98493]! [Fig. 10)]. Distribution: Mexico (Veracruz [Fig. 6]), Guatemala, Honduras, Nicaragua, Costa Rica, Venezuela, Suriname, Cuba, Jamaica, Haiti, Dominican Republic, and Martinique. Specimen: MEXICO. Veracruz: Cosautlán de Carvajal, Flores-Palacios s.n. (XAL, photo!). 17. Acianthera tikalensis (Correll & C.Schweinf.) Pridgeon & Chase (2001: 246). Pleurothallis tikalensis Correll & Schweinfurth in Correll (1965: 190). Holotype: GUATEMALA. Petén: Tikal National Park, bordering Aguado Seca, 14 October 1959, Contreras 280 (LL[370341]!). Acianthera markii Archila (2009: 11). Type: GUATEMALA: Department of Alta Verapaz, city of Senahu, Sepacuite Farm, 15 August 2006, 990 m, Archila FA-211 (BIGU[37301]). Distribution: Mexico (Chiapas, Campeche, Quintana Roo [Fig. 6]), Guatemala, and Belize. A taxonomic synopsis of Acianthera Phytotaxa 218 (1) 2015 Magnolia Press 51

14 Specimens: MEXICO. Chiapas: Ocosingo, Ribera del Rio Lacantún, frente al rancho Puerto Rico, 170 m, 20 February 1999, Sinaca 2354 (MEXU!); Ocosingo, alrededores de Nuevo Palestina, 550 m; Ocosingo, Estación Biológica Chajul, 200 m, Martínez et al (AMO!); Ocozocoautla de Espinosa, Zona Sujeta a Conservación Ecológica Laguna Bélgica, Moreno s.n. (HEM!); Yajalón, 800 m, 11 November 1971, Breedlove & Smith (CAS!). Campeche: Aguada de Zoh Laguna, en las afueras del poblado, 180 m, 17 April 1995, Soto 7703 (AMO!); Calakmul, 500 m al N del poblado 11 de Mayo, 225 m, 15 October 1997, Lira 204A (MEXU!); Calakmul, 2 km al N de San Miguel, 200 m, 6 December 1998, Martínez et al (MEXU!); al sur de Xpujil, 300 m, Andrews sub Hagsater 3942 (AMES!); Calakmul, cerca de las ruinas de Río Bec, Ibarra sub Hágsater (AMO!). Quintana Roo: Felipe Carrillo Puerto, 22 km al S de Felipe Carrillo Puerto, Catling & Brownell M10.4 (AMES!). Notes: Acianthera markii is only known from the specimen type collected in Guatemala, which comprises a minute, pendulous plant. The flowers of this species, however, are phenetically similar to Acianthera tikalensis in size and shape; thus, these plants are morphologically indistinguishable. The locality of A. markii is within the range of A. tikalensis; the Archila specimen most likely corresponds to a dwarf plant of this species. 18. Acianthera unguicallosa (Ames & C.Schweinf.) Solano in Hágsater & Soto (2003: 512). Pleurothallis unguicallosa Ames & Schweinfurth (1930: 195); Ogygia unguicallosa (Ames & C.Schweinf.) Luer (2006: 252). Type: MEXICO. Colima: Socorro Island [Revillagigedo Island], 5 May 1925, Mason 1628 (holotype CAS[6393]!, isotypes AMES[74824]! CAS[6392]!). Distribution: Mexico (Colima [Fig. 6]). Specimens: MEXICO. Colima: Manzanillo, Isla Socorro, 800 m, 18 January 1958, Miranda 8746 (MEXU!); Manzanillo, SE flank of cerro Evermann, 825 m, 12 April 1978, Moran (MEXU!); Manzanillo, Isla Socorro, Volcán Evermann, 1000 m, 11 August 1987, Campos& Toriz 629 (ENCB! MEXU!). Notes: Acianthera unguicallosa is the westernmost species in the genus Acianthera and most likely in subtribe Pleurothallidinae. Geographically, this species is restricted to Socorro Island, in Revillagigedo Archipelago (Pacific ocean), almost 693 km away from Manzanillo coast, Colima, Mexico. 19. Acianthera violacea (A.Rich. & Galeotti) Pridgeon & Chase (2001: 246). Pleurothallis violacea Richard & Galeotti (1845: 16). Humboltia violacea (A.Rich. & Galeotti) Kuntze (1891: 668). Lectotype (according to Solano & Soto In Hágsater & Soto, 2003: 513): Tabula 1, Fig. 2 published in the original description (W[12696]! drawing of the type at AMES[74855]!). Pleurothallis amoena Richard & Galeotti (1845: 16). Humboltia amoena (A.Rich. & Galeotti) Kuntze (1891: 667). Type: MEXICO. Cordillera [Hidalgo]: Real del Monte, 7,000 ft. June October 1840, Galeotti 5228 (P[489152]! lectotype here designated [Fig. 7], isolectotype W[21883]! drawing at AMES[74042]!). Pleurothallis cochlearis Reichenbach (1852: 764). Humboltia cochlearis (Rchb.f.) Kuntze (1891: 667). Holotype: MEXICO. Unknown locality, cultivated Im Dresdener botanischen Garten [flowered in] 1844 (W!). Pleurothallis rhynchoglossa Schlechter (1915: 91). Type: MEXICO. Veracruz: Bei Zacuapan, flowered in cultivation March 1914, Purpus s.n. (holotype B ; lectotype designed by Solano & Soto Arenas in Hágsater & Soto Arenas (2003: 513: Tab 6, fig. 8 15) published with the original description). Distribution: Mexico (Hidalgo, Veracruz, Oaxaca, Chiapas [Fig. 6]), Guatemala, and El Salvador, reported in Honduras by Ossenbach et al. (2007). Specimens: MEXICO. Hidalgo: Real del Monte, 1840, Galeotti 5228 (P! W!). Veracruz: Valle de Cordoba, 10 March 1866, Bourgeau 2083, 2083A (P!); Xico, Nagel sub Oestlund 4775 (AMES!). Oaxaca: San Miguel Metepec, 2,600 m, Suárez 556 (AMO[photo]!). Chiapas: Ocosingo, Laguna Ocotalito, 950 m, 27 April 1989, Soto 5615 (AMO!); Cacahoatán, 1,320 m, 4 April 2014, Damon s.n. (ECOSUR!). Notes: Pleurothallis amoena and P. violacea were simultaneously published by Richard & Galeottti (1845), but the description of P. amoena was listed first; since only recently Pleurothallis amoena was recognized as synonym for P. violacea (Hágsater & Soto Arenas 2003, Luer 2004), therefore the latter name has established priority as the species basyonym. Luer (2004) proposed that the specimen Galeotti 5228 is both holotype for P. violacea and P. amoena; however, this proposal was incorrect. Because the description of P. violacea includes an illustration, herein it was chosen as its lectotype, leaving the Galeotti s specimen as lectotype for P. amoena. 52 Phytotaxa 218 (1) 2015 Magnolia Press SOLANO GOMEZ

15 Figure 7. The specimen Galeotti 5228 deposited at P(489152) and designated here as lectotype of Pleurothallis amoena A.Rich. & Galeotti. Reproduction with permission of the Muséum National d Histoire Naturelle, Paris. A taxonomic synopsis of Acianthera Phytotaxa 218 (1) 2015 Magnolia Press 53

16 Figure 8. The specimen duplicated of Bernoulli & Cario 496 deposited in K[583978] and designated here as neotype for Pleurothallis carioi Schltr. Reproduction with permission of The Board of Trustees of the Royal Botanical Gardens, Kew. 54 Phytotaxa 218 (1) 2015 Magnolia Press SOLANO GOMEZ

17 Figure 9. Reproduction of Tabula 296. Fig. I II. 1 6 published in Xenia Orchidaceae (Wendland & Kränzlin, 1900), which was chosen here as lectotype for Pleurothallis hartwegiifolia H.Wendl. & Kraenzl. A taxonomic synopsis of Acianthera Phytotaxa 218 (1) 2015 Magnolia Press 55

18 Figure 10. The illustration based on the type of Cryptophoranthus pectinatus Schltr. and deposited at AMES[98493]. Reproduction with permission of the Oak Ames Orchid Herbarium, Harvard University. 56 Phytotaxa 218 (1) 2015 Magnolia Press SOLANO GOMEZ