Columnea angulata J.L. Clark & Tobar, 2021

Clark, John L., Tobar, Francisco, Clavijo, Laura, Perret, Mathieu & Graham, Catherine Helen, 2021, Three new species of Columnea (Gesneriaceae) from the western Andean slopes of Ecuador and Colombia, PhytoKeys 182, pp. 67-82 : 67

Columnea angulata J.L. Clark & Tobar sp. nov.

Figs 2 , 3

Diagnosis.

Differs from Columnea picta by a shallow bilabiate corolla limb (vs. deeply bilabiate corolla limb) and a corolla perpendicular to oblique relative to the calyx (vs. corolla straight relative to the calyx).

Type.

Ecuador Imbabura: cantón Cotacachi , parroquia Garcia Moreno , Cordillera de Toisan , Cerro de la Plata , Bosque Protector Los Cedros, sendero Camino del Oso, north of lodge, 0°18'N, 78°46'W, 1500-2600 m, 19 Mar 2003, J.L. Clark, F. Nicolalde & R. Hall 7413 (holotype: US [ US 3492386]; isotypes: AAU, COL, K, MO, QCA, QCNE, SEL, UNA) .

Description.

Facultative epiphyte with dorsiventral shoots to 1.5 m long, subwoody, suffrutescent, glabrescent below, sparsely pilose above; internodes 7-10 cm near base, then clustered at branch apex. Leaves opposite, strongly anisophyllous, papyraceous when dry; larger leaf nearly sessile, petioles 0.1-0.4 cm long, pilose; blade asymmetric, oblanceolate to oblong, 7-28 × 2-9.5 cm, base oblique, apex acuminate, margin serrate, adaxially uniformly dark green to red with dark red apex, glabrous, abaxially light green, upper regions of margins, and apical third of leaf dark red, sparsely pilose to densely pilose along the venation, lateral veins 7-15, primary and secondary veins occasionally red; smaller leaf sessile, sometimes appressed to the dorsal surface of stem; blade asymmetric, lanceolate 0.5-2 × 0.4-0.6 cm, base oblique, apex acuminate, margin serrate, green with red apex on both surfaces, glabrous adaxially, sparsely pilose to densely pilose along the venation and margins abaxially. Inflorescence reduced to a single axillary flower (rarely 2-3); peduncles absent or highly reduced (<0.2 cm); bracts 1-2, light green, lanceolate, 0.7-1.2 × 0.2-0.4 cm, glabrous on both sides. Flowers subtended by elongate pedicels, 1.5-2.5 cm long, sparsely to densely pilose, tightly appressed to the abaxial leaf surface when immature, becoming pendent during anthesis; calyx lobes 5, nearly free, mostly equal in size and shape, dorsal lobe slightly smaller, lobes appressed to flower when immature and spreading during anthesis, from uniformly yellow, to red with yellow margins, to yellow with a large reddish mid-region, 1.5-3.5 × 0.5-1 cm, ovate to broadly oblong, apex acuminate to acute, margin serrate, pilose on both surfaces; corolla tubular, appearing perpendicular to calyx via a sigmoid-shaped corolla tube, 2.1-3.5 cm long, outer and inner surfaces pilose, base appearing laterally compressed, limb shallowly bilabiate, white suffused with yellow on lower two thirds, more yellow toward apex, splotches of dark red on lower portion of lateral and ventral lobes, light yellow patch below lobes, red streaks abaxially, lobes 0.3-0.4 × 0.3-0.5 cm. Androecium of 4 stamens, filaments connate at the base and forming a filament curtain for 0.2-0.4 cm, free portion of filaments 3-3.5 cm long, glabrous; anthers longer than broad, ca. 2 × 1.5 mm, dehiscing by longitudinal slits; staminode absent; nectary a bilobed dorsal gland, glabrous; ovary superior, densely pilose, 0.2-0.4 × 0.2 cm, style ca. 2.5 cm long, glabrous, stigma included and shallowly bifid. Fruit not observed.

Phenology.

This species has been found with flowers in two periods: February to May and August to October.

Etymology.

The specific epithet is in reference to the angulate or bent corolla tube. The corolla is nearly perpendicular to the calyx lobes because of the sigmoid-shaped tube.

Distribution and preliminary assessment of conservation status.

Columnea angulata is locally abundant in forests along the western slopes of the Ecuadorian Andes in the provinces of Cotopaxi, Imbabura, Pichincha, and Santo Domingo de los Tsáchilas (Fig. 1 ) where it grows in mature forests and the shaded understory of recently cleared forests, from 1500 to 2600 m in elevation. It is especially common along the old highway between Quito and Santo Domingo. It has been documented in two protected areas: Reserva Florística-Ecológica Río Guajalito and Bosque Protector Los Cedros. According to the IUCN Red List criteria ( IUCN 2001) for limited geographic range (B1, less than 20,000 km2) and considering the uncertain future of habitat conservation of western Andean forests (B2b, c), Columnea angulata should be listed in the category Vulnerable (VU).

Comments.

Columnea angulata is unique from other Columnea by the posture of the pendent mature flowers where the corolla tubes are oriented oblique to perpendicular relative to the calyx (Figs 2A , 3B ). Another defining character is a constriction at the base of the corolla tube that makes it appear laterally compressed (Fig. 2C ). Columnea picta and C. angulata are vegetatively similar and grow sympatrically. These two species are differentiated by the presence of deeply bilabiate corolla tubes in Columnea picta (Fig. 6A ) in contrast to the shallowly bilabiate corolla tubes in C. angulata (Fig. 2B, C ). Columnea angulata differs from C. tecta by an elongate corolla tube (vs. corolla tube that does not exceed the calyx lobes in C. tecta ) and single axially flowers (rarely 2-3) in contrast to the abundant clusters of 3-5 axially flowers in C. floribunda . Columnea picta and C. angulata are the two most commonly collected species in this complex and readily differentiated by the entire calyx margin in C. picta and serrate calyx margin in C. angulata .

Specimens examined.

Ecuador Cotopaxi: cantón Sigchos, parroquia San Francisco de las Pampas, Bosque Integral Otonga , 0°25.17'S, 79°0.19'W, 1900 m, 26 Jan 2001, J.L. Clark and Muñoz 6125 (QCA, QCNE, SEL, UNA, US) ; Pichincha: cantón Quito, parroquia Nono , El Pahuma Orchid Reserve , 17 km east of Nanegalito , 0°1'S, 78°37'W, 1700 m, 17 Apr 2003, J.L. Clark et al. 7648 (QCA, QCNE, SEL, UNA, US) ; cantón San Miguel de los Bancos, Mindo Loma Cloud Forest Reserve , km 73.5 via Calacali-La Independencia , 3 km past the entrance to the village of Mindo , 0°0'44"S, 78°44'29"W, 1800 m, 23 May 2011, J.L. Clark & C. Aulestia 12198 (QCNE, UNA, US) ; cantón San Miguel de los Bancos, Las Gralarias Reserve , 1.2 km east of the lodge , 0°05'N, 78°43'W, 1900 m, 15 Aug 2017, F. Tobar, A. Nieto, A. Marcayata & S. Imba 2832 (QCA); cantón San Miguel de los Bancos, Las Gralarias Reserve , Puma trail , 0°05'N, 78°43'W, 1900 m, 21 May 2018, F. Tobar, F. Richter 3280 (QCA); cantón San Miguel de los Bancos, Puyucunapi Reserve , cultivada cerca de la casa de la reserva , 0°01'N, 78°41'W, 1800 m, 13 Oct 2019, F. Tobar & M. Gavilanes 3409 (HPUCESI, QCNE); cantón San Miguel de los Bancos, a 2.6 km al este de San Tadeo en la vía a Bellavista Lodge, 0°01'N, 78°44'W, 1893 m, 11 Mar 2020, F. Tobar & M. Gavilanes 3475 (QCNE); cantón San Miguel de los Bancos, Puyucunapi Reserve , a 800 m de la entrada del transecto principal , 0°01'N, 78°41'W, 1995 m, 12 Mar 2020, F. Tobar & M. Gavilanes 3479 (QCA); Santo Domingo de los Tsáchilas: cantón Santo Domingo de los Colorados, Bosque Protector Rio Guajalito, located on the old Quito-Santo Domingo road, between Chiriboga and La Palma , 0°18'50"S, 78°55'35"W, 1796 m, 30 May 2009, J.L. Clark et al. 10968 (NY, QCNE, SEL, US) ; Reserva Florística-Ecológica Río Guajalito, km 59 de la carretera antigua Quito-Sto. Domingo de los Colorados , a 3.5 km al NE de la carretera, 0°13'53"S, 78°48'10"W, 1800-2200 m, 3 Apr 2003, J.L. Clark, N. Muchhala & A. Hoyos 7618 (QCA, QCNE, SEL, UNA, US) .

Figures

Figure 1. Distribution of Columnea angulata (circles), C. floribunda (triangles), C. tecta (squares), and C. picta (asterisks). Note that C. picta ranges from southern Ecuador to northwestern Colombia (exceeding the range of the currently described species) (Map generated by Marco Monteros).

Figure 2. Columnea angulata J. L. Clark & F. Tobar A mature flower B front view of flower C ventral view of flower showing laterally compressed corolla tube D dorsiventral habit (A, D from J. L. Clark et al. 12198 B from J. L. Clark 10968 C from J. L. Clark et al. 7413). Photos by J. L. Clark.

Figure 3. Columnea angulata J. L. Clark & F. Tobar A dorsiventral habit B lateral view of flower C dissected corolla showing filaments and ventral view of the anthers D dorsal view of the anthers E lateral view of ovary and nectary gland F dorsal view of nectary gland G lateral view of calyx and style, showing shallowly bifid stigma H lateral view of flower. Illustrated by M. J. Gavilanes, based on F. Tobar et al 3409.

Figure 6. Columnea picta H. Karst A lateral view of flower featuring deeply bilobed corolla B ventral view of flower during anthesis C mature flower featuring curled lower lobe D dorsiventral habit (A, B from J. L. Clark & L. Jost 16301 C from J. L. Clark et al. 15393 D from J. L. Clark, M. Mailloux & S. Seger 7942). Photos by J. L. Clark.