Besleria santaclarensis Clavijo & Sanchez-Taborda, 2020

Sanchez-Taborda, Jhon A., Zuluaga, Alejandro & Clavijo, Laura, 2020, A new species of Besleria (Gesneriaceae) from the Serrania El Pinche (Cauca), southwestern Colombia, PhytoKeys 162, pp. 71-80 : 71

Besleria santaclarensis Clavijo & Sanchez-Taborda sp. nov. Figs 1 , 2

Type.

Colombia, Cauca: Municipio Argelia, corregimiento Santa Clara, vereda Santa Clara, Reserva Forestal Protectora Regional “Serranía El Pinche", flanco oriental de la Serranía que se desprende de la vertiente pacífica de la Cordillera Occidental, camino por el borde de la quebrada La Planada, 2°23.938'N, 77°18.863'W, 1620 m. 25 Sep 2017 (fl), Jhon Alexander Sánchez-Taborda, Álex Cortés, Andrea Borrero, Fernando Joaqui, Andrés Pérez, Erminson Buitrago, Julian Uetochambo 2552 (holotype: COL!; isotype: CUVC!).

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.

Terrestrial subshrub, 1-1.5 m tall. Stem erect, sometimes scandent, branched, terete in cross section, 1.9-4 mm diam., subwoody, green, surface smooth to longitudinally striated, strigose toward the apex, trichomes <1 mm long, unbranched, white; internodes 1.7-5.8 cm long. Leaves opposite, equal in a pair, sometimes subequal, older leaves usually caducous; petiole 1.6-4.9 cm long, slightly winged in cross-section, glabrate in basal leaves, strigose in apical leaves, trichomes <1 mm long, white; blades elliptic, coriaceous, papyraceous when dry, 6.4-17.6 × 2.8-6.8 cm, green and glossy adaxially, olive green abaxially, apex acuminate, base cuneate, sometimes oblique, margin entire, glabrate on both surfaces, 7-10 pairs of secondary veins, obscure adaxially and raised abaxially with scarce and whitish indument, higher order of venation only evident abaxially. Inflorescence a pair-flowered cyme, axillar, usually in the leafless axils near the base of the stem, up to 8 flowers per inflorescence; peduncle and bracts absent. Pedicel oblique to perpendicular relative to the stem, 8.6-17.1 mm long, maroon, glabrous. Calyx magenta, membranous, persistent in fruit, venation evident, reticulated; calyx lobes 5, 4 nearly equal, free, apex acute, base truncate to cordate, margin entire, glabrous on both surfaces, ventral and lateral lobes 9-13 × 6.2-10.6 mm, ovate, dorsal lobe 10.1-11.9 × 4.3-5.3 mm, oblong; Corolla zygomorphic, protandrous, slightly gibbous, thick, 14.4-15.4 mm long, orange, glabrous; corolla tube slightly constricted above the base and then slightly ventricose ventrally, oblique relative to calyx, 12.3-13.5 mm long, 5.7-6.2 mm at its widest part, constriction above the base 3.7-4 mm diam., base 5.4-6.8 mm wide; throat 2.3-2.8 mm diam., inner surface with glandular trichomes; corolla lobes 5, subequal, orange, spreading, ovate, apex rounded, margin entire, glabrous on both surfaces, ventral lobe 1.4-2.6 × 2.4-3.1 mm, lateral lobes 2.5-3.4 × 2.4-3.9 mm, dorsal lobes 0.8-1.1 × 1.8-2.3 mm. Androecium of 4 stamens, didynamous, included; filaments 7.1-10.1 mm long, adnate to the corolla tube for 1.9-2.6 mm, forming a sheath, glabrous, coiling after anthesis, staminode 4.9-5.2 mm long; anthers reniform, 1.2-1.4 × 1.1-1.7 mm, coherent by the apex and lateral walls, dehiscence by longitudinal slits. Gynoecium with an annular nectary gland, 0.5-0.7 mm tall, glabrous; ovary superior, 3-3.1 × 2.5-2.7 mm wide, rounded, glabrous; style included, 6.4-6.8 mm long, glabrous; stigma bilobed. Fruit a berry olive green; seeds numerous.

[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) between 1300 and 1600 m above sea level, on the Pacific slope of the Cordillera Occidental of the Andes. It is frequent in open areas and in forest clearings, usually near to crops, pastures and remnants of secondary and riparian forests, whose canopies reach up to 35 m and 25 m, respectively. These forests have typical Andean floristic elements, represented by the genera Saurauia Willd ( Actinidaceae ), Schefflera J.R. Forst. and G. Forst. ( Araliaceae ), Axinaea Ruiz and Pav. ( Melastomataceae ), Ladenbergia Klotzsch ( Rubiaceae ), Wettinia Poepp, Socratea H. Karst and Iriartea Ruiz and Pav. ( Arecaceae ), Cyathea Sm and Alsophila R. Br. ( Cyatheaceae ).

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, 2017), based on the small population of the species, with an estimated area of occupancy of less than 20 km2, and the continued habitat loss, due to the high concentration of illicit crops in the area ( UNODC 2019).

Figures

Figure 1. Drawing of Besleria santaclarensis Clavijo & Sanchez-Taborda, sp. nov. A habit B leaf detail, adaxial view C calix, lateral view D flower, frontal view E corolla, lateral view F interior view of corolla showing stamens and staminode G gynoecium with anular nectary gland H fruit, lateral view. Illustration by Adriana Sanin, based on the holotype Sanchez-Taborda et al. 2552.

Figure 2. Besleria santaclarensis Clavijo & Sanchez-Taborda, sp. nov. A branch showing leaf and inflorescence B inflorescence showing flower in lateral view C inflorescence showing an immature fruit D frontal view of the corolla. (Photographs by Jhon A. Sanchez-Taborda from the paratype).

Figure 3. Distribution map of Besleria santaclarensis and Besleria membranacea.