Palicourea horquetensis (Dwyer & Hayden) A. C. Berger & C. M. Taylor, 2017

Berger, Andreas, 2017, Two new combinations, lectotypifications and a new name for Costa Rican Palicourea s. l., PhytoKeys 80, pp. 53-63 : 53

Palicourea horquetensis (Dwyer & Hayden) A. C. Berger & C. M. Taylor comb. nov.

Rudgea horquetensis Basionym. Dwyer & Hayden, Ann. Missouri Bot. Gard. 54(2): 145-146, 1967.- Type: PANAMA. Chiriquí: Distr. Boquete, Cerro Horqueta, ca. 1980 m, 26 Jul 1940, C. von Hagen & W. von Hagen 2156 (holotype: NY barcode 133202!).

Coussarea nebulosa = Dwyer, Ann. Missouri Bot. Gard. 67(1): 131, 1980a. ≡ Psychotria nebulosa (Dwyer) C. M. Taylor, Novon 5(2): 205, 1995, nom. illeg. hom., non Psychotria nebulosa K. Krause, Bot. Jahrb. Syst. 57(1): 46-47, 1920. ≡ Palicourea nebulosa (Dwyer) C. M. Taylor, Novon 20(4): 488, 2010.- Type: PANAMA. Chiriquí: Monte Rey near Boquete, ca. 1170 m, 20 Jul 1971, T. B. Croat 15868 (lectotype, designated by Taylor (1995): PMA barcode 1189! ex MO 2162999 [sheet # 1/2]; isolectotype: MO barcode MO 312217! [sheet # 2/2]).

Rudgea chiriquiensis = Dwyer, Ann. Missouri Bot. Gard. 67(2): 476, 1980b. ≡ Coussarea chiriquiensis (Dwyer) C. M. Taylor, Fieldiana, Bot., n.s. 33: 113, 1993.- Type: PANAMA. Chiriquí: Cerro Colorado, along road above San Félix, 29 km above bridge over Río San Félix, 7.9 km above turnoff to Escopeta, 1500 m, 14 Jul 1976, T. B. Croat 37071 (lectotype, designated by Taylor (1995): MO barcode MO-312257!; isolectotype: PMA barcode 1163! ex MO 2389189).

Nomenclatural remarks.

Rudgea horquetensis Dwyer & Hayden was accepted as a species of Rudgea by most authors including Lorence (1999) and Correa et al. (2004). Lorence and Taylor (2012) were the first to exclude it from Rudgea , but did not suggest any further placement. Based on morphological characters, the species clearly belongs to the nocturnally flowering species group of Palicourea ( Taylor et al. 2010) and is here treated as conspecific with Psychotria or Palicourea nebulosa . Rudgea horquetensis is the oldest available name for the taxon and a respective new combination is proposed here.

Typification.

The protologue of Coussarea nebulosa states that the holotype is located at MO. At the time of publication two sheets of the type collection have been accessioned at MO, making the holotype designation ambiguous. In 1975, Dwyer annotated both sheets as Coussarea nebulosa , but did not specify what sheet he intended to be the holotype. Hence, both specimens represent syntypes (ICN, Art. 40.2 & Note 1; see also McNeill 2014). Later, the specimens were annotated as sheet “1” and "2 of 2", respectively. Sheet 1 was also annotated as holotype by C. M. Taylor in 1988.

Taylor (1995) cited the above-mentioned sheets as "holotype, MO 2162999; isotype, MO 4043108" which has to be considered a valid (though indirect) lectotypification according to the ICN (Art. 7.10, 9.9, 9.23; see also McNeill 2014). Later, Lorence (1999) cited the specimens as "Holotype MO 2162995; Isotype MO 4043108". The last digit of the numbering stamp on the corresponding sheet is hardly legible as a “9”, possibly explaining the error in citation. In the last revision of the group ( Taylor et al. 2010), the erroneous type citation of Lorence (1999) was repeated. In a repatriation project in 2001 (C. M. Taylor, pers. comm.), the lectotype (specimen 1) was deaccessioned and distributed to PMA. The sheet still bears a respective MO accession number stamp.

A similar case of indirect lectotypification is found in Rudgea chiriquiensis. The species was described with reference to two collections at that time housed at MO, one of which was later distributed to PMA. Likewise, lectotypification (of the MO sheet) was achieved by Taylor (1995).

Distribution.

Palicourea horquetensis is only known from few sites in Costa Rica and Panama.