Drymonia longiflora J.L.Clark & Clavijo, 2022

Clark, John L. & Clavijo, Laura, 2022, Two new species of Drymonia (Gesneriaceae) from Northwestern South America, including the discovery of the longest flower known in the genus, PhytoKeys 190, pp. 1-14 : 1

Drymonia longiflora J.L.Clark & Clavijo sp. nov.

Fig. 4

Diagnosis.

Differs from all Drymonia by an elongate corolla that exceeds 6.5 cm in length, the longest corolla known in the genus. The subshrub habit with elongate shoots and corolla shape are similar to Drymonia macrophylla and D. peponifera . Drymonia macrophylla has a corolla that rarely exceeds 3.5 cm in length and D. peponifera has a corolla that rarely exceeds 4.5 cm in length.

Type.

Ecuador. Esmeraldas: cantón San Lorenzo, parroquia Alto Tambo, remnant patch of primary forest on north side of road between Durango and Alto Tambo on highway San Lorenzo-Ibarra , 0°57'19"N, 78°33'30"W, 695 m, 29 May 2008, J.L. Clark, B. Bisvicuth, S. Ginzbarg & J. Melton III 10442 (holotype: US; isotypes: COL, E, G, MO, NY, QCNE, SEL).

Description.

Terrestrial, hemiepiphytic or epiphytic herb or subshrub, with scandent to horizontal shoots to 1 m long. Stems subquadrangular in cross-section, 0.3-0.6 cm in diameter, strigose to glabrate, internodes 1.0-8 cm long. Leaves opposite, decussate, usually evenly spaced and becoming clustered near apex, subequal to unequal in a pair; petioles 0.7-3.0 cm long, basal enations present, strigillose to strigose, terete in cross-section; blade elliptic to ovate, 8.0-28 × 3.5-13 cm, membranous to subcoriaceous, the base rounded to acute, sometimes oblique, the apex acute to long-acuminate, the margin serrulate, the upper surface glossy-green, glabrescent or strigose, the lower surface light green with red venation, glabrescent or strigillose, lateral secondary veins 5-7 pairs, prominent abaxially, strigose abaxially. Inflorescence reduced to a single flower in the upper or lower leaf axils; peduncle absent; bracts small, lanceolate, 3.0-7.0 × 1.1-1.3 mm, green, lanceolate, strigose; pedicels short, 3-7 mm long, green, strigose. Flowers with calyx green, dark red with green margins, or uniformly dark red, with enations at base; lobes 5, nearly free, 4 equal, the upper lobe slightly smaller and more narrow, membranous, lanceolate with an elongate acute apex, the margins deeply serrate to slightly laciniate, lobes covered with sparsely pilose trichomes, 1.5-2.7 × 0.3-0.5 cm. Corolla zygomorphic, tubular, elongate, 6.5-8.0 cm long, with slight spur (nectar chamber) at base, 0.5-0.7 cm long; the corolla tube perpendicular relative to calyx, ampliate toward the limb, not contracted above, 5.0-6.5 cm long, 0.5-1.1 cm wide at the mid portion, uniformly pale yellow and sericeous outside, usually darker yellow inside; throat to 1.4 cm in diameter, the inside yellow, sometimes with brown spotting on lower portion, sparsely pilose or glandular; limb with 5 spreading lobes, subequal, globose, rounded at apex, margins erose, glabrous abaxially and adaxially, lobes 5-10 × 4-11 mm, the lower lobe slightly larger. Androecium of 4 didynamous stamens, included; filaments 5-6 cm long, adnate to the base of the corolla tube for 2-3 mm, glabrous, coiled after anthesis; the anthers at first coherent, after anthesis separating, dehiscent by basal pores, 3-5 × 2-1.8 mm. Gynoecium with a single dorsal nectary gland, thick, ovate, 2-3 mm long, glabrous; the ovary superior, sericeous, green; style included, 5-6 cm long, white, puberulent; stigma stomatomorphic. Fruit and seeds 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 elongate corolla tube, the longest of any known species of Drymonia .

Distribution and preliminary conservation assessment.

Drymonia longiflora is locally abundant in forests along the western slopes of the northern Andes in Ecuador (Provinces Carchi and Esmeraldas) and Colombia (Departments Chocó, Valle del Cauca, and Nariño). One disjunct population is documented from southern Ecuador (Province Morona-Santiago). Drymonia longiflora grows in mature shaded forests, from 150 to 900 m in elevation. We provisionally assess this new species as Vulnerable (VU), according to the IUCN Red List criteria ( IUCN 2022) for limited geographic range (EOO <20,000 km2 and AOO <2,000 km2) and associated subcriteria, including occurrence at fewer than ten locations (B2a) and continuing decline of Andean forests (B2b).

Comments.

Drymonia longiflora is distinguished by the longest known corolla recorded for Drymonia (> 6.5 cm). The unbranched subwoody epiphytic or terrestrial subshrub habit and the foliage are similar to Drymonia macrophylla , D. fimbriata , and D. peponifera . All four species are vegetatively similar, but readily differentiated by corolla tube length and calyx lobes (Fig. 5C, D ). The calyx lobes of Drymonia peponifera appear crispate from the reflexed and undulating lobes (Fig. 5C, D ). In contrast, the calyx lobes of D. macrophylla (Fig. 3D ) and D. longiflora (Fig. 4D ) are flat. The margins of the calyx lobes in Drymonia longiflora are serrate to slightly laciniate, in contrast to the strongly laciniate with unbranched filiform teeth of D. fimbriata . The corolla in Drymonia longiflora exceeds 6.5 cm in length (Fig. 4D ). In contrast, the corolla rarely exceeds 3.5 cm in D. macrophylla (Fig. 3D ) and D. fimbriata . The corolla is less than 4.5 cm in D. peponifera (Fig. 5D ). Drymonia longiflora and D. intermedia share similar shapes for corolla tubes and calyx lobes, but differ in size, with D. intermedia much smaller. A summary of diagnostic characters is provided in Table 1 .

Our preliminary DNA sequence data strongly support a close relationship in a clade that includes D. intermedia , D. laciniosa , D. longiflora , D. macrophylla , and D. peponifera . This clade is defined by fleshy capsular fruits with tardily dehiscent endocarps. A photographic guide and description of fruit types is summarized in Clark and Clavijo (2022). Most Drymonia capsules have endocarps that dehisce when mature. In contrast, the clade that includes D. intermedia and D. longiflora is defined by endocarps that remain attached and surround the placentae and mass of funiculi and seeds (Figs 1B , 5B ). The endocarp eventually becomes dehiscent at a later stage when it detaches from the reflexed outer layers of the fruit wall (Fig. 5B ). Although we have not observed mature fruits of Drymonia longiflora , we predict that the fruit type of this species shares the same characters with closely related congeners.

Specimens examined.

Colombia. Chocó: 2 km south of Las Animas on road to Istmina, 150 m, 13 Aug 1976, A. Gentry & M. Fallen 17620 (COL); Valle del Cauca: municipio Buenaventura, carretera vieja a Benaventura, 900-1500 m Apr 1998, M. Amaya-M. & J.F. Smith 594 (COL, US); municipio Buenaventura, Los Tubos, Pericos, vertiente occidental de cordillera occidental, km 43 Cali-Buenaventura, 3°51'00"N, 76°47'19"W, 521 m, 30 Aug 2011, J. Home 228 (CUVC); Bajo Calima, concesión Pulpapel/Buenaventura, carretera a San Isidro, 3°55'N, 77°W, 100 m, 30 Sep 1987, M. Monsalve B. 1865 (CUVC, MO); road Cali-Buenaventura, further down the road towards Buenaventura, about 4 km, 1 May 1972, H. Wiehler, R.L. Dressler, N.H. Williams & N.F. Williams 72106 (SEL); municipio Dagua, Vereda Yatacue, sitio La Riqueza, camino desde el tunel a las torres, 3°35'40.6"N, 76°53'31.8"W. 630-780 m, 20 Jan 2019, L. Clavijo, M. Perret, K. Arango, A. Zuluaga & W. Villar 2231 (COL, CUVC, G). Nariño: municipio Barbacoas, corregimiento El Diviso, vereda El Verde, western slopes of the Cordillera Occidental, remnant forest along highway between Altaquer and El Diviso, 1°21'46"N, 78°10'32"W, 795 m, 13 May 2013, J.L. Clark, L. Clavijo, O. Marín & M. Flores 13417 (COL, CUVC, SEL, US); municipio de Ricaurte, Resguardo Indígena Nulpe Medio, camino a la quebrada La Conga, 1°6'N, 78°13'W, 750 m, 8 Jan 1996, M.S. González & B.R. Ramírez-P. 1606 (PSO); municipio de Ricaurte, Resguardo Indigena Nulpe Medio Andalucía, quebrada La Babosa, 1°5'N, 78°14'W, 780-815 m, 12 Jan 1996, M.S. González & B.R. Ramírez-P. 1678 (PSO). Ecuador. Carchi: border area between Carchi and Esmeraldas, about 30 km past Lita on road Lita-Alto Tambo, 450 m, 28 Jun 1991, H. van der Werff, B. Gray & G. Tipas 12113 (MO, QCNE, SEL, US). Esmeraldas: cantón San Lorenzo, parroquia Alta Tambo, Awá Indigenous Territory, Río Bogotá community (future biological research station), 2 km S of Lita-San Lorenzo road, near Quebrada Pambilar, 0°58'57"N, 78°35'60"W, 350-600 m, 12 Feb 2003, J.L. Clark, G. Zapata & G. Toasa 7129 (MO, QCNE, SEL, UNA); cantón San Lorenzo, parroquia Alta Tambo, border region of Awá Indigenous Territory, entrance to the Río Bogotá community (future biological research station), near Quebrada Pambilar, 0°58'57"N, 78°35'50"W, 350-600 m, 13 Feb 2003, J.L. Clark 7197 (F, MO, QCNE, SEL, UNA, US); parroquia Alto Tambo, trail from the community Durango to Río Tululbi via trail north of San Lorenzo-Ibarra highway, forest managed by Fundacion Sirua, 1°2'50"N, 78°36'54"W, 150-200 m, 28 May 2008, J.L. Clark, B. Bisvicuth & J. Melton III 10343 (MO, NY, QCNE, SEL, US); cantón San Lorenzo, remnant patch of forest along the Ibarra-San Lorenzo highway, between Durango and Alto Tambo, 1°0'33"N, 78°35'58"W, 516 m, 3 Jun 2009, J.L. Clark J.L. Clark & The 2009 Gesneriad Research Expedition Participants 11113 (MO, NY, QCNE, SEL, US); cantón San Lorenzo, remnant patch of forest along highway Ibarra - San Lorenzo, between Durango and Alto Tambo, 1°0'33"N, 78°35'58"W, 516 m, J.L. Clark & The 2009 Gesneriad Research Expedition Participants 11127 (QCNE, SEL, US); cantón Eloy Alfaro, Reserva Ecológica Cotachi-Cayapas, parroquia Luis Vargas Torres, Río Santiago, 0°49'S, 78°45'W, 250 m, 8 Dec 1993, M. Tirado, P. Asimbaya, M.I. Corosa & V. Arroyo 776 (MO, QCNE, US); cantón San Lorenzo, San Francisco, recinto Durango, sector Colinado, terrenos propiedad Sr. Demetrio Paez, 1 km al este de la carretera Lita-San Lorenzo, 1°2'N, 78°36'W, 256 m, 17 Oct 1999, J.C. Valenzuela & E. Freire 474 (QCNE, MO, US). Morona-Santiago: Región de la Cordillera del Cóndor y Cordillera de Cutucú, Cordillera de Shaime, al norte del Río Santiago, Centro Shuar Jempekat, 2°57'S, 77°50'W, 600 m, 15 Oct 2003, G. Toasa 9343 (MO, QCNE).

Figures

Figure 1. Drymonia intermedia Clavijo & J. L. Clark A holotype specimen B upper view of mature fruit C front view of corolla D lateral view of flower (A holotype (SEL) of J. L. Clark et al. 10442 B from J. L. Clark et al. 7148 C, D from J. L. Clark et al. 10344). Photos by J. L. Clark.

Figure 3. Drymonia macrophylla (Oerst.) H. E. Moore A erect subwoody habit B mature fleshy bivalved capsule C front view of corolla D lateral view of flower (A from P. Pedraza et al. 850 B from J. L. Clark et al. 12119 C, D from J. L. Clark et al. 10044). Photo A by P. Pedraza and photos B-D by J. L. Clark.

Figure 4. Drymonia longiflora J. L. Clark & Clavijo A erect subwoody habit B mature calyx lobes C front view of corolla D lateral view of flower (A from J. L. Clark et al. 7196 B from J. L. Clark et al. 13417 C, D from J. L. Clark et al. 10343). Photos by J. L. Clark.

Figure 5. Drymonia peponifera J. L. Clark & Clavijo A habit B upper view of mature fruit C lateral view of immature calyx lobes D lateral view of axillary inflorescence with a single mature flower (A-D from J. L. Clark & L. Jost 6957). Photos by J. L. Clark.