A new species of Besleria (Gesneriaceae) from the Serranía El Pinche (Cauca), southwestern Colombia

Abstract A new species of the genus Besleria (Gesneriaceae), endemic to the department of Cauca, Colombia, is described and illustrated here. The new species, Besleria santaclarensis Clavijo & Sánchez-Taborda, was discovered in the Regional Protective Forest Reserve “Serranía El Pinche”, Cordillera Occidental of the Colombian Andes. B. santaclarensis is distinguished by the epedunculate inflorescences, usually in the leafless axils near the base, with up to eight orange flowers, and by the magenta calyx that covers 2/3 of the corolla.


Introduction
Besleria Plum. ex L. includes 160 species (Clark et al. 2020) of terrestrial herbs, shrubs and small trees that grow in the rainforest understory. It is strongly supported as mono-phyletic in the tribe Beslerieae (Smith 2000;Roalson and Clark 2006;Clark et al. 2010). Biogeographic analyses of the family suggest that it diversified in the Andes 15 Mya (Perret et al. 2013;Roalson and Roberts 2016). Besleria is one of the largest and least known genera among the New World Gesneriaceae; it occurs in most Neotropical rainforests with the highest diversity in the tropical Andes (>100 species), followed by Central America (20 species) (Skog and Boggan 2007;Ferreira et al. 2016). Colombia is the country with the highest diversity of Besleria, with more than 80 species (Cortés 2013), followed by Peru with 35 (Kvist et al. 2005), Ecuador with about 20 (Skog and Kvist 1997) and Panama with 15 (Skog 1978). In Colombia, most of the species are found in the humid forests of the Andes and the Choco Biogeographic region, whereas few species grow in the Amazon (Cortés et al. 2017). In the Andes, the largest number of species is found in the Cordillera Occidental of Colombia. For example, Besleria is the third largest Gesneriaceae genus with 10 species out of the 96 recorded in northern Valle del Cauca (Clavijo et al. 2014). Likewise, Pedraza and Betancur (2015) recorded five species of Besleria out of the 70 Gesneriaceae species collected in the National Natural Park Orquídeas (Antioquia), north of the Cordillera Occidental.
The Serranía El Pinche in Argelia (Cauca) is located in the southern portion of the Cordillera Occidental of the Colombian Andes, and is part of the Munchique-Pinche corridor, a region known for high levels of biodiversity (Paz-B et al. 2018). Biogeographically, the Serranía El Pinche is more similar to the Nudo de los Pastos and the Colombian Massif than to the northern portions of the Cordillera, mainly due to the lower elevation Paramos on the Pacific slopes (Becking 1995). For the first settlers of the Serranía, the conservation of native ecosystems and sustainable rural development were paramount in this biodiverse region. Early settlers inspired in their children the importance of preserving their natural resources by creating alliances that would allow the proper management and establishment of a formal protected area. As a result of this initiative, the Regional Protective Forest Reserve "Serranía El Pinche" was created in 2008. The Reserve is part of the San Juan de Micay river basin that ranges in elevation from 1040 to 3744 meters above sea level; it has 7,256 ha, however, after its expansion it will have in total 11,930 ha. 90.4% of the reserve corresponds to primary forests and 9.6% to perturbed forests, crops and pastures. The Reserve "Serranía El Pinche" and the buffer zone include 913 households (Paz-B et al. 2018).
The upper San Juan de Micay river basin is a unique biodiverse area in the Pacific slopes of the Andes that still has large extensions of primary tropical rainforests (Becking 1995), despite high deforestation rates caused by agriculture and the presence of illicit crops. The preservation of protected areas led by local communities in regions suffering rapid deforestation is essential to conserve species and entire ecosystems. In fact, private and community-owned protected areas have been successful in preserving natural ecosystems in the northern Andes, where biological diversity is high (Joppa et al. 2008;Armenteras et al. 2009;Rodríguez et al. 2013). Therefore, following the legacy of the first naturalists and ecologists that explored La Serranía El Pinche, we aim to contribute to the floristic knowledge of this underexplored rainforest in southwestern Colombia. The plant inventory and discovery of new taxa in this region will provide important information to support the future expansion of the Reserve toward the coast, in the municipalities of Guapi and Timbiquí, achieving a broad elevation coverage from the Pacific coast to the paramos of the Andean highlands.

Methods
During a rapid ecological evaluation carried out in September of 2017 to characterize the vegetation and establish the baseline for expanding the Regional Protective Forest Reserve "Serranía El Pinche", we discovered a new species of the genus Besleria which is described and illustrated here.
The collections of the new species were processed at the herbarium of the Universidad del Cauca (CAUP) and were deposited at the Colombian National Herbarium (COL), the herbarium of the Universidad del Valle (CUVC) and the Botanical Garden of Medellin (JAUM). Specimens of Besleria from COL, CUVC, and JAUM were studied to confirm the identity of the species. The photographs were taken with a Nikon camera model D 5300. For the general botanical terminology we followed Beentje (2010) and Moreno (1984 Besleria santaclarensis is distinguished by epedunculate inflorescences, usually in the leafless axils near the base of the stem, with up to 8 glabrous orange flowers, and magenta glabrous calyx that covers 2/3 of the corolla.
[Measurements from flowers during the mature gynoecium phase.] Distribution and ecology. Besleria santaclarensis is endemic to Colombia and known only from the type locality in the municipality of Argelia (Cauca) in the Regional Protective Forest Reserve "Serranía El Pinche" and surrounding areas (Fig. 3). This species grows in the lower montane rainforest (Holdridge 1967)  Phenology. Besleria santaclarensis has been found in flower in February and September and in fruit in February. Etymology. Besleria santaclarensis is named after the type locality, the Santa Clara village, in the municipality of Argelia, Cauca. The territory currently known as Argelia and areas surrounding El Pinche mountain range were initially inhabited by the Guapios indigenous people, until the arrival of the colonists who named it the Agua Clara path, due to the streams of crystalline waters present in the area. Afterwards, during evangelization, a Franciscan priest changed the name to Santa Clara because of the fertility of the land, which he called holy (Alveiro Bolaños, personal communication).
Preliminary conservation status. Besleria santaclarensis is only known from the Regional Protective Forest Reserve "Serranía El Pinche" and surrounding areas. Although the Reserve is a protected area, deforestation and soil degradation caused by agriculture and livestock systems, as well as the presence of illicit crops in the surrounding areas, may have a significant impact on the integrity of this narrow endemic species. B. santaclarensis is present in mature forests, but it is also frequent in open areas in remnants of secondary and riparian forests, suggesting it is resilient and capable of thriving in disturbed areas. A preliminary designation of Endangered (EN) category is provided, according to the criterium B2ab (IUCN 2012(IUCN , 2017, based on the small population of the species, with an estimated area of occupancy of less than 20 km 2 , and the continued habitat loss, due to the high concentration of illicit crops in the area (UNODC 2019).

Discussion
Besleria santaclarensis can be readily distinguished from its congeners by the epedunculate inflorescences, usually in the leafless axils near the base of the stem, with up to 8 glabrous orange flowers, and magenta glabrous calyx that covers 2/3 of the corolla. B. santaclarensis is similar to B. membranacea C.V. Morton in their foliage, their flowers with membranous and glabrous calyx, and their slightly gibbous and glabrous corolla tube. B. membranacea is endemic to Peru, particularly to the Amazon and the eastern foothills of the Andes, in the Departments of Loreto and San Martín, mainly in the basin of the Huallaga and Aguaytía rivers, between 260 and 880 m of elevation (Salinas and León 2006). B. santaclarensis differs from B. membranacea by shorter petioles (1.6-4.9 cm vs. (3.2-)6.5-11.6 cm), inflorescences with up to 8 flowers (vs. up to 4), shorter pedicels (8.6-17.1 mm vs. 13.1-20 mm), calyx base truncate to cordate (vs. never cordate), larger calyx lobes (9.0-13.0 × 4.3-10.6 mm vs. 5.8-9.3 × 1.6-4.7 mm) that cover up to 2/3 of the corolla (vs. covering up to 1/2 of the corolla), and corolla tubes shorter (14.4-15.4 mm vs. 14.9-18 mm long) and orange (vs. yellow and white). Additionally, B. santaclarensis is similar to an undescribed species collected in the Province of Zamora-Chinchipe, Ecuador, by Dr. John Clark (Clark et al. 10815). The two species share the inflorescences with several orange flowers with magenta ovate calyx lobes, but differ in that B. santaclarensis has glabrous calyx (vs. pilose) and slightly gibbous and glabrous corolla tube (vs. gibbous and pilose).
With the discovery and description of B. santaclarensis we aim to contribute to the floristic knowledge of this underexplored rainforest in southwestern Colombia, and to provide new information to support the future expansion of the Reserve that will warrant the conservation of this and many other species.