Drymonia silvaniae J. L. Clark, 2025

Clark, John L., 2025, Four new species of Drymonia (Gesneriaceae) from South America: Tributes to inspirational leaders, PhytoKeys 256, pp. 37-59 : 37-59

Drymonia silvaniae J. L. Clark sp. nov.

Figs 7 , 8

Diagnosis.

Differs from all other congeners by the longitudinal red striations contrasting with white on the inside of the corolla tube. Shares similar nomadic climbing habit with D. coccinea but differs by the shorter corolla (<2.8 cm long vs corolla tube> 3.5 cm long) and relatively smaller leaves.

Type.

Ecuador • Napo: Zamora-Chinchipe, parroquia Zurimi , Cabañas Yankuam , Sendero Vino Tinto , trail on opposite side of road from Cabañas Yankuam, 800–1000 m, 4°15'54"S, 78°54'34"W, 12 May 2009, J. L. Clark & University of Alabama in Ecuador Program Participants 10733 (holotype: SEL!; isotypes: ECUAMZ, US!) .

Description.

Elongate scandent subwoody nomadic vines with leaves in the subcanopy (ca. 10 m above ground) and flowers produced near the forest floor along a leafless portion of the stem. Stems elongate and subwoody, terete in cross section, 3–6 mm in diameter. Leaves opposite, equal in a pair; petiole 2–6 cm long, green, terete in cross-section; blade broadly elliptic to ovate, 13–27 × 5–10 cm, coriaceous, adaxially light green, abaxially green when alive and turning dark red when dry, apex acute to acuminate, base acute, sometimes slightly decurrent along the petiole, margin entire, 5–7 pairs of secondary veins, sparsely pubescent with single-celled trichomes abaxially, adaxially glabrous. Inflorescences produced along a leafless region of stem near ground, of pair-flowered cymes that elongate from displaced bracteoles, often reaching 5 cm in length, each inflorescence branch subtended by a pair of persistent bracts; bracts uniformly puberulent, oval and uniformly red, ca. 1.5 × 1.5 cm.; each inflorescence with one mature open flower at a time; Flowers campanulate and laterally compressed; pedicels 5–7 mm long. Calyx white to white suffused with red, glabrous, base of calyx with prominent enations, lobes 5, lobes nearly free, fused at the base for 2–4 mm, overlapping, imbricate, but clasping corolla tube, lobes broadly ovate, apex rounded, base broadly ovate, margins entire, ventral and lower lobes ca. 1.8 × 1.2 cm, the dorsal lobe slightly smaller, ca. 1.5 × 1.0 cm. Corolla tube zygomorphic, protandrous, oblique to perpendicular relative to calyx, to 2.8 cm long, gibbous at base, constricted laterally throughout, 5–8 mm wide, outside mostly glabrous at base and puberulent near apex, inside glabrous with minute glandular trichomes near apex, throat elliptic in cross section and nearly constricted laterally, lobes 5, subequal, margins entire to erose, lobes reflexed, 5–6 × 5–6 mm, each lobe white with prominent horizonal red striations that extend into the corolla throat. Androecium of 4 didynamous stamens, included, filaments broad and flat, ca. 1.8 cm long, adnate to the corolla tube for 3 mm, white, glabrous; anthers oblong, sagittate, coherent by the lateral walls, dehiscence initially by basal pores that develop into longitudinal slits, 4.2–7.0 × 0.7–2.0 mm. Gynoecium with a single bilobed dorsal gland; ovary superior, 4.0–5.0 × 4.0–5.0 mm, cone-shaped, puberulent to velutinous; style stout, included, 1.4 cm long; stigma stomatomorphic. Fruit and seeds not observed.

Specimens examined.

Ecuador • Zamora-Chinchipe: cantón Nangaritza, Cordillera del Condor, trail from Cabañas Yankuam (west of Cabañas Yankuam ) towards waterfall that is owned and operated by ATASMO ( Asociación de Trabajadores Autónomos San Miguel de las Orquídeas ), 912 m, 4°15'0.4"S, 78°39'36.4"W, 11 Mar 2017, J. L. Clark, J. A. Mayr & D. A. Neill 15296 ( ECUAMZ, MO, SEL, US) ; • same locality, 6 Mar 2019, J. L. Clark & A. Wilcox 16000 ( ECUAMZ, QCA, MO, NY, SEL, US) .

Phenology.

Collected with flowers in March and May. Fruits not observed.

Etymology.

The specific epithet honors Silvana G. Nazzaro Clark, Head of School at Princeton Junior School (Princeton, NJ). The name Silvana is of Latin origin, derived from silva, meaning “ forest ” or “ woodland, ” and translates roughly to “ woman of the forest ” or “ woodland maiden. ” This name reflects a connection to nature, wilderness, and vitality — qualities Silvana has exemplified since childhood and carried into adulthood. She has accompanied and supported the author in a lifelong pursuit of studying biodiversity. Through her current and previous leadership roles, she has championed programs that nurture a new generation of lifelong learners. Her efforts have inspired a deep appreciation for the natural world, fostering curiosity and environmental stewardship in others.

Distribution.

Drymonia silvaniae is endemic to the Ecuadorian province of Zamora-Chinchipe along the eastern Andean slopes in southern Ecuador at elevations between 800 and 1000 meters.

Comments.

Drymonia silvaniae displays a unique color pattern compared to any currently known species of Gesneriaceae . Its white, laterally compressed tubular corollas (Figs 7 & 8 ) are marked with elongate longitudinal striations, resembling the patterns found on candy canes often associated with the winter holiday season. The abaxial leaf surfaces dry a distinct dark red, sharply contrasting with the dark or light green surfaces observed in other species described here.

Figures

Figure 7. Field images of Drymonia silvaniae J. L. Clark A front view of corolla B lateral view of corolla C lateral view of flower D, E inflorescence (A, C from J. L. Clark et al. 15296 B, D from J. L. Clark et al. 16000 E from J. L. Clark et al. 10733). Photos by J. L. Clark.

Figure 8. Illustration of Drymonia silvaniae J. L. Clark A adaxial leaf surface B habit featuring foliage and inflorescence C inflorescence with mature flower D front view of corolla E lateral view of corolla F lateral view open flower featuring gynoecium G lateral view of open flower featuring androecium (A – G from J. L. Clark et al. 10733). Illustration by Sue Blackshear.