Solanum tavinuuyuku J. M. Bryant & Tepe, 2025

Solanum tavinuuyuku J. M. Bryant & Tepe sp. nov.

Fig. 6 View Figure 6

Diagnosis.

Solanum tavinuuyuku resembles Solanum ionidium Bitter , but is distinguished from that species by its long and narrow, lanceolate, ovate to falcate, simple to 3 - foliate leaves with 7–10 secondary veins, large and persistent pseudo-stipules, sparse to dense pubescence and white to violet-tinged corolla color that is especially pronounced in the floral bud.

Type.

Mexico. Oaxaca • Distr. Santiago Juxtlahuaca. Mpio. Santiago Juxtlahuaca. Loc. Puerta de Luz, hacia la torre microondas, entrada por Santa Rosa, via San Miguel Cuevas a El Manzanal , 17.13°N, 98.03°W, 2405 m elev., 18 Apr 1995 (fl), J. I. Calzada 19831 (holotype: MEXU! [892615]; isotypes: LL! [00218235], NY! [ NY 00751674 ]) GoogleMaps .

Description.

Vine, trailing along ground or climbing on other vegetation to 10 m or more, rooting at the nodes. Stems woody, sparsely to densely pubescent with long, transparent to pale tawny, unbranched, eglandular, multicellular simple hairs (termed finger-hairs in Seithe and Anderson (1982)), 0.5–0.8 mm long, more densely pubescent at the nodes, the stems often with white lenticels. Sympodial units plurifoliate, not geminate. Leaves distichous, simple to 3 - foliate pinnately compound, tending towards 3 - foliate on juvenile vegetative shoots and simple on mature shoots, the blades 2–14 × 1–5 cm, chartaceous, the margins flat to somewhat revolute, not ciliate, lamina sparsely to densely pubescent to glabrescent abaxially and adaxially, but on average, more densely pubescent adaxially, on veins and on developing leaves, the rachis and petiolules densely pubescent with multicellular finger hairs; simple leaves 3.8–11 cm × 1.5–3.5 cm, ovate, lanceolate to narrowly elliptic in shape, somewhat falcate on some specimens, the bases acute to rounded, symmetrical to asymmetrical, the apices acute to acuminate, the acumen 0.3–1 cm long, venation pinnate, (5 –) 7–10 pairs of secondary veins, secondary veins curved; compound leaves include an apical leaflet and a single pair of lateral leaflets, the distal lateral leaflet often smaller than its counterpart or completely absent; apical leaflets of compound leaves 5.5–9 cm × 2–3 cm, substantially larger than lateral leaflets, ovate to lanceolate, the bases acute, rounded to nearly truncate, symmetrical to asymmetrical, the apices acuminate, the petiolules 1.5–2.5 mm; lateral leaflets 2–4.5 cm × 0.5–2 cm, elliptic to ovate, the apices acute, the petiolules nearly lacking to 1 mm; interjected leaflets absent; petioles 0.3–5 (– 8.6) cm, densely pubescent. Pseudo-stipules present at nearly every node, single, persistent, 3–5 × 6.5–10 mm, reniform or more rarely subovate, the apices sharply acute, pubescence resembling that of the leaves. Inflorescences terminal corymbose-cymes, 2–3 × branched, 1.5–2.2 cm × 2–2.5 cm in flower, 3.5–6 cm × 2.5–4 cm in fruit, with 6–15 flowers distanced 0.5–3 mm apart, the axes glabrous, glabrescent or less frequently moderately pubescent, the peduncle 1–5 (– 11) mm, becoming extra-axillary with added sympodia, occasionally presenting a single bract-like leaf opposite the branching point; pedicels 0.2–1.2 cm in flower, 1–1.5 cm in fruit, articulated at the base, 0.5 mm wide across the base, expanded distally in flower and fruit up to 2 mm, moderately pubescent in flower with scattered, long, slender, finger hairs, 0.3–0.8 mm, glabrescent to glabrous in fruit. Flowers pentamerous, apparently perfect, but dimorphic, morphologically complete, with anthers from pistillate flowers producing inaperturate pollen. Calyx campanulate, 1.5–2.5 mm × 1.5–3 (– 6) mm in developing buds, 3–3.5 mm × 3–4 mm on mature flowers, the tube 1–1.5 mm long in flower and fruit, 5 - lobed, the lobes triangular with acute to apiculate apices, 1–1.5 mm × 1–1.5 mm in flower, 1.5–2.5 mm × 1.5–2.5 mm in fruit, the margins somewhat scarious, the lobes with short, stocky, clustered pubescence on the apices, 0.02–0.3 mm and often sparsely to densely pubescent with long, slender, appressed, finger hairs, 0.3–0.7 mm, across the entire calyx, glabrescent in fruit. Corolla 0.8–1.2 cm in diameter, stellate, 5 - lobed, reflexed or flat at anthesis, the tube 1.5–2.5 mm, the lobes 3.5–6 mm × 2–2.5 mm, ovate to triangular, acute at apices, puberulent on apices and along the distal half to third of the margins, violet with white along petal margins (as visible on herbarium material), violet color pronounced on developing buds. Stamens equal, with filaments 0.3–1 mm long, free to partially fused to half the entire filament length, pubescent; anthers 2.8–3.1 mm × 1–1.2 mm, oblong with retuse apices, cordate at the bases, connivent, yellow, with large apical pores, developing into introrsely dehiscent longitudinal slits with age. Ovary glabrous; the style on short-styled, staminate flowers 1–3 mm or nearly absent, far shorter than stamens, cylindrical, the stigma slightly clubbed or truncate; the style on long-styled, pistillate flowers 5.5–6 mm, exserted above the stamens, curved at the tip, cylindrical, the stigma capitate. Fruits 0.3–1 cm in diameter, globose, green when immature to bright orange-red at maturity, glabrous. Seeds 3.5–4 mm × 2.2–3 mm, flattened, rounded to teardrop-shaped, with a 0.2–0.5 mm wide wing around the margins, the thickened part of the seed 2.5–3 mm × 2–2.5 mm, rounded to oval-shaped, lenticular, light to medium brown, the surface smooth, the wing yellowish-tan to translucent near the margins, with radial striations, 15–20 seeds per fruit.

Distribution and ecology.

Solanum tavinuuyuku appears to be endemic to south-central Mexico and has been collected in extreme western Oaxaca (Mixteca and Sierra Sur Regions) through central Guerrero (La Montaña and Centro Regions). These areas are a part of the Sierra Madre del Sur ecoregion, where S. tavinuuyuku grows in the understory of pine-oak forests and montane cloud forests, from 1700 to 2840 m in elevation (Fig. 7 View Figure 7 ).

Phenology.

Solanum tavinuuyuku appears to flower year-round. Flowering specimens have been collected January, April, August, October and December; fruiting specimens are from January, August and October.

Etymology.

The epithet tavinuuyuku is of Mixtec origin and is derived from a combination of the Mixtec words tavi nuu yuku, which can be roughly translated to mean “ found growing in the mountains ”. We acknowledge that the very act of naming of natural objects is political. Taxonomists have and are still often guilty of acquiring these natural entities as their own intellectual possession, dictating, in a sense, the language in which we communicate about the world we inhabit. Nonetheless, it is our intent that by choosing this name, we honor the contributions of all indigenous nations and peoples in documenting and conserving local biodiversity, particularly the Mixtec people who inhabit these landscapes. Although we were not able to discover a local name for this plant, we propose an epithet sourced from a language familiar to the people who have undoubtedly interacted with it for millennia.

Conservation statement.

IUCN Red List Criteria ( IUCN 2022) suggest a status of vulnerable (VU) for S. tavinuuyuku , based on criteria B 1 a, b (i, iii) with an extent of occurrence (EOO) of ca. 18,582 km 2. The species is known from only eight localities and is either quite rare or particularly under-collected (Fig. 1 View Figure 1 ). The Sierra Madre del Sur ecoregion is composed primarily of rugged terrain, can be quite remote and thankfully is a conservation priority in Mexico ( Arriaga Cabrera et al. 2000). However, the forest habitats where S. tavinuuyuku grows are under threat from ranching and agricultural activities in the area ( Toledo-Aceves et al. 2011) which may impact the demographic and ecological stability of the species in the future if current trends continue.

Specimens examined.

Mexico. Guerrero • 2 km al NE del Campamento El Gallo; estribaciones SW del Cerro Teotepec , 2650 m elev., 27 Jan 1965 (fl, fr), J. Rzedowski and McVaugh 159 ( CORD, F, MEXU [photo]) • Mun. Eduardo Neri, along highway between Milpillas (on Highway 95) and Atoyac de Alvarez, 3.7 mi W of turn-off on to road to Chichihualco , 17.08°N, 99.73°W, 2325 m elev., 14 Jan 1979 (fl, fr) T. B. Croat 45621 - a ( BM [photo], F, MO, NY, US) GoogleMaps • Along road between Milpillas at Highway 95 and Atoyac de Alvarez (near Highway 200) 3.5 miles west of junction with road to Chichihualco , 2425 m elev., 12 Jan 1979 (fl), T. B. Croat 45517 ( MO) • 15 km al E de Pto. del Gallo, Carr. Filo de Caballo. Mpio. Chichihualco , 3090 m elev., 18 Aug 1982 (fl), L. Hernandez S. and C. Romero de T. 1414 ( MEXU [photo], NY) . Oaxaca • Distr. Santiago Juxtlahuaca, Mpio: San Martin Peras , 17.18°N, 98.11°W, 2565 m elev., 10 Oct 1994 (fl, fr), J. I. Calzada 19434 ( LL, MEXU [photo], NY) GoogleMaps • Mun. San Martin Peras, Loc. Dt. de Juxtlahuaca. A 3 km de la desviación a San Martin Peras, hacia Coicoyán de las Flores , 17.28°N, 98.22°W, 3 Dec 1992 (fl) Torres et al. 14098 ( MEXU [photo]) GoogleMaps • Distr. Putla, Mpio. Santa Cruz Itundujia, A 7.37 km en LR (SE) de Santa Cruz Itundujia , 16.82°N, 97.63°W, 2865 m elev., 1 Aug 2008 (fl, fr) Gutierrez et al. 3075 ( MEXU [photo], SERO [photo]) GoogleMaps .