Columnea pendens F.Tobar, J.L.Clark & J.F.Sm., 2022

Tobar, Francisco, Smith, James F. & Clark, John L., 2022, Two new pendulous epiphytic Columnea L. (Gesneriaceae) species from the Choco forests of the Northern Andes, PhytoKeys 196, pp. 49-61 : 49

Columnea pendens F.Tobar, J.L.Clark & J.F.Sm. sp. nov.

Fig. 5

Type.

Ecuador. Carchi, Espejo, road between Goaltal and Chical, near to rio Gualpi , 0.890555°N, 78.2188889°W, 1786 m, 12 Sep 2021, F. Tobar 3638 (holotype: QCA; isotype: QCNE) .

Diagnosis.

Similar to Columnea ceticeps , differing in the bright orange corollas (vs. bright red corollas in C. ceticeps ), calyx lobes broadly ovate (vs. narrowly elongate in C. ceticeps ), corolla tube ventricose (vs. uniformly tubular in C. ceticeps ), and corolla tube densely pubescent (vs. corolla tube sparsely pubescent in C. ceticeps ).

Description.

Epiphytic herb with elongate pendent shoots, 1.2-1.5 m long, brown, with zigzag appearance, glabrous near base, pilose with gold-colored trichomes near apex; internodes 2.0-4.5 cm long. Petioles 0.1-0.2 cm long, pilose with multicellular gold-colored trichomes; leaves opposite, pairs usually, nearly equal to isophyllous, rarely anisophyllous, 0.6-6.0 cm long, 0.3-2.3 cm wide, ovate to elliptic, apex acuminate, base slightly oblique, lateral veins 3-8 per side, adaxially dark-green, with white trichomes, abaxially green to red-purple, densely pilose with multicellular gold-colored trichomes and single-celled white trichomes, margin crenulate to serrulate. Inflorescence reduced to 1 or 2 flowers per axil; bracts not seen, presumably caducous. Pedicels 0.3-1.3 cm long, green or red, appressed pilose with multicellular gold-colored trichomes. Calyx clasping, lobes 1.2-2.3 cm long, 0.25 cm wide, triangular-ovate to broadly triangular-ovate, apex long acuminate, exterior densely pilose, with multicellular gold-colored trichomes, interior glabrous, margin serrulate. Corolla 5.2-6.1 cm long, 0.6-1.1 cm at widest point (apex of corolla limb, near throat), tubular, medially ventricose, gibbous at base, 2.8-3.5 mm wide at narrowest point at the base, bright orange externally, interior yellow, exterior densely pubescent with multicellular red-colored trichomes, interior with sparse short trichomes and some stalked glandular trichomes; limb bilabiate, upper lip with two fused dorsal lobes and two lateral lobes, lower limb with an extended ventral lip; dorsal lobes connate, rounded to subquadrate, ca. 6.2 mm long, ca. 6.5 mm wide; lateral lobes triangular to narrowly triangular, ca. 1.5 mm long, ca. 2.0 mm wide; ventral lobe, narrowly oblong to linear ca. 1.9 cm long and ca. 2.8 mm wide, galea 1.9 cm long. Filaments ca. 5.1 cm long, connate for ca. 0.5 cm and adnate to base of corolla, anthers ca. 1.4 mm long, ca. 1.3 mm wide, included in the corolla throat, quadrangular. Ovary 3.4 mm long, conical, pubescent or glabrous, with multicellular transparent trichomes; style pale yellow to white, pilose with multicellular transparent and short stalked glandular trichomes; stigma unlobed, papillate, included in corolla tube. Nectary a bilobed dorsal gland. Mature fruit and seeds not seen.

Phenology.

Collected in flower during February-April, and September. Immature fruits observed in April.

Etymology.

The specific epithet refers to the pendent epiphytic habit.

Distribution and preliminary assessment of conservation status.

Columnea pendens is endemic to the western Andean slopes of Ecuador and Colombia (Fig. 1 ). The forest is located in the broadly defined ecoregion referred to as the Chocó Biogeographic Region or the Tumbes-Chocó-Magdalena biodiversity hotspot.

The Ecuadorian populations are known from the provinces of Santo Domingo de los Tsáchilas and Carchi (Fig. 1 ). The Ecuadorian population from Santo Domingo de los Tsáchilas is located on the road that connects the village 23 de Julio with San Juan de Chiriboga. Several populations from Carchi are located near Río Gualpi, between 1500 and 1800 m. According to the vegetation classification system by the Ecosystems of Continental Ecuador ( MAE 2012), the Ecuadorian forest is classified as Bosque siempreverde montano bajo de Cordillera Occidental de los Andes (BsBn04) (lower montane evergreen) and represents a narrow band of vegetation between 1400 and 2000 meters, that ranges from the Carchi province in the north to the Santo Domingo de los Tsáchilas province in the south. Current protected areas in Ecuador that correspond to montane evergreen forest include the Ecuadorian national park (Ministerio del Ambiente del Ecuador), Cotacahi-Cayapas Ecological Reserve, and several private reserves such as Los Cedros Biological Reserve, Maquipucuna Cloud Forest Reserve, and Río Guajalito.

The Colombia populations are known from Cerro Plateado, Cerro Pinche, and Munchique in the Cauca department, and La Planada in the Nariño department (Fig. 1 ). The Colombian forests that host populations of C. pendens correspond to premontane, montane, pluvial, and cloud forests along the Pacific slopes of the Cordillera Occidental (western mountain range). Current protected areas in Colombia that correspond to known populations of C. pendens include the community-based reserve, La Reserva Natural La Planada, in the Nariño department in southern Colombia. In addition, populations of C. pendens are located in the Munchique National Natural Park, part of the Colombian Sistema Nacional de Áreas Protegidas, in the Cauca department.

Based on the available information and According to the IUCN Red List criteria ( IUCN 2012; IUCN Standards and Petitions Committee 2019) C. pendens is preliminary assessed as Endangered (EN) based on fewer than five known populations (criteria B1 + 2a), EOO <5000 km2, and AOO <500 km2.

Comments.

Columnea pendens is similar to C. ceticeps , which was recently described from Colombia and northern Ecuador ( Smith et al. 2013b). The geographic distribution for these two species overlaps in northern Ecuador and southern Colombia (Fig. 1 ). Columnea pendens has uniformly bright orange corollas (Fig. 5A ) in contrast to the uniformly bright red corollas in C. ceticeps (Fig. 4A ). The calyx lobes of C. pendens are broadly ovate (Fig. 5A ) in contrast to the narrowly elongate calyx lobes of C. ceticeps (Fig. 4A ). The corolla in C. pendens is medially inflated or ventricose and covered in uniformly dense (nearly tomentose) pubescence (Fig. 5A ) in contrast to a sparsely pubescent corolla in C. ceticeps (Fig. 4A ).

Specimens examined.

Colombia. Cauca: toward south end of La Depresion, between Cerro Pinche and Cerro Plateado, 26 Sep 1994, E.L. Core 1358 (US); El Tambo, O. Haught 5200 (US); El Tambo, Munchique Jul 1948 S. Yepes Agredo 472 (US). Nariño: Reserva Natural La Planada , Ricaurte , on the road near Quebrada Dulce , 3 Mar 1989, J.F. Smith & P. Galeano 1522, (COL, WIS). Ecuador. Carchi: canton Mira , via Gualchan-El Carmen-Chical , 0.4166667°N, 78.216666°W, 1900-2000 m, 2 Nov 2014, AJ Perez et al. 7716 (QCA). Santo Domingo de los Tsáchilas: cantón Santo Domingo, road between 23 de Julio y San Juan de Chirboga , 0.239444°S, 78.848611°W, 1891 m, 21 April 2021, F. Tobar & G. Rueda 3644 (QCA) .

Figures

Figure 1. Distribution of Columnea ceticeps (squares), C. fluidifolia (triangles), and C. pendens (circles). Note that range of C. ceticeps extends into the Colombian departments of Choco, Antioquia and Risaralda (not featured here) (map provided by Marco F. Monteros).

Figure 4. Columnea ceticeps J. L. Clark & J. F. Sm. A mature flower B pendent shoot C deeply bilabiate corolla D calyx lobes (A-D from J. L. Clark 12950 D photos by J. L. Clark.

Figure 5. Columnea pendens F. Tobar, J. L. Clark & J. F. Sm. A mature flower B pendent shoot C gynoecium and androecium D calyx lobes (A-D from F. Tobar 3638). Photos by F. Tobar.