Solanum longifilamentum Saerkinen & P. Gonzales , PhytoKeys 44: 42. 2015.

Knapp, Sandra, Saerkinen, Tiina & Barboza, Gloria E., 2023, A revision of the South American species of the Morelloid clade (Solanum L., Solanaceae), PhytoKeys 231, pp. 1-342 : 1

29. Solanum longifilamentum Saerkinen & P. Gonzales, PhytoKeys 44: 42. 2015.

Figs 89 , 90

Type.

Peru. Pasco: Prov. Oxapampa, Dist. Huancabamba, Parque Nacional Yanachaga-Chemillén, sector Tunqui, riberas del rio Muchuymayo , alrededores del hito PNYC, 1,790 m, 22 Oct 2008, M. Cueva, A. Peña, R. Rivera & M. Moens 276 (holotype: USM [acc. # 00268971]; isotypes: HOXA, HUT, MO [MO-2507305, acc. # 6455431]) .

Description.

Delicate herbs to small subwoody subshrubs, 0.2-1 m high, single stemmed or occasionally branching at the base. Stems terete to ridged, often tinged with purple, sparsely pubescent with appressed 1-2-celled simple uniseriate trichomes ca. 0.2 mm long. Sympodial units difoliate, not geminate. Leaves simple, the blades 2.5-12 cm long, 1-4 cm wide, ovate-lanceolate, membranous, somewhat discolorous; adaxial surface glabrous; abaxial surface with appressed 1-2-celled simple uniseriate trichomes like those of the stem along the veins; principal veins 4-8 pairs; base cuneate to attenuate, slightly unequal and oblique; margins entire; apex acuminate; petiole 0.5-1 cm long, sparsely pubescent with simple uniseriate trichomes like those of the stems and leaves, especially on young growth. Inflorescences internodal, unbranched, 1.5-3 cm long, with 3-5(6) flowers often all apparently arising from the same place, sparsely pubescent with simple uniseriate trichomes like those of the stems and leaves; peduncle 1-1.5 cm long, often tinged with purple; pedicels 0.5-0.6 cm long, ca. 0.4 mm in diameter at the base and 0.5 mm at apex, straight and spreading at anthesis, articulated at the base; pedicel scars closely spaced a maximum of 1 mm apart. Buds conical, white, occasionally purple-tinged towards the base, the corolla strongly exserted from the calyx tube long before anthesis. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube ca. 1.5-2 mm long, the lobes 1-1.5 mm long, deltate to triangular with acute apices, slightly reflexed at anthesis, sparsely pubescent with simple uniseriate trichomes like those of the stems and leaves. Corolla 0.5-0.6 cm in diameter, stellate, white with a yellow, purple or black central star at the base, lobed 2/3 to nearly to the base, the lobes ca. 3-3.5 mm long, 1.5-2 mm wide, strongly reflexed at anthesis, later spreading, purple towards tips, densely pubescent abaxially with 1-2-celled simple uniseriate trichomes, these usually shorter than the trichomes of the stems and leaves. Stamens equal; filament tube minute, pubescent with a few scattered 3-5-celled trichomes at the base adaxially; free portion of the filaments ca. 1.1-1.4 mm long, pubescent like the tube; anthers (1.7-)3-3.4 mm long, 0.8-0.9 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary globose, glabrous; style 3.5-4 mm long, straight, short-exserted beyond the anther cone, densely pubescent in lower 1/4 with 2-3-celled simple uniseriate trichomes; stigma globose, minutely papillate, pale yellow in live plants. Fruit a globose berry, 0.6-0.7 cm in diameter, green at maturity or green and turning purplish black when ripe, the pericarp thin, shiny, somewhat translucent, glabrous; fruiting pedicels 1-1.2 cm long, ca. 0.6 mm in diameter at the base, 0.9 mm in diameter at the apex, spreading, not persistent; fruiting calyx lobes 1.8-3.5 mm long, spreading, the tips reflexed. Seeds 35-45 per berry, ca. 1.2 mm long, ca. 1.1 mm wide, tear-drop shaped, narrower at one end, brownish orange, the sub-lateral hilum positioned towards the narrower end of the seed, the testal cells pentagonal in outline. Stone cells 4-8 per berry, 0.4-0.5 mm in diameter, scattered throughout, white to cream-coloured. Chromosome number: not known.

Distribution

(Fig. 91 ). Solanum longifilamentum is distributed from Ecuador (Provs. Azuay, Cañar, Chimborazo, Loja, Napo, Pastaza, Pichincha, Zamora-Chinchipe) to Peru (Depts. Amazonas, Ayacucho, Cajamarca, Cusco, Huánuco, Junín, Pasco, Puno, San Martín, Ucayali) and Bolivia (Depts. Beni, Cochabamba, La Paz, Santa Cruz) along the eastern slopes of the Andes.

Ecology and habitat.

Solanum longifilamentum grows in mid-elevation montane forests in moist areas, along roadsides, often amongst mosses and small herbs; from (200-) 1,000 to 2,800 (-3,500) m elevation. In the Huancabamba depression in northern Peru (e.g., Kujikat 104), plants have often been collected at lower elevations.

Common names and uses.

Ecuador. Pastaza: wampishkúr (Shuar Jívaro, Lewis 14172). Peru. Cajamarca: mortiño (Spanish; Särkinen et al. 4577). Stems and leaves crushed and applied with achiote ( Bixa orellana L., Bixaceae ) warm to treat skin irritations ( ‘papera’) (Lewis 14172).

Preliminary conservation status

( IUCN 2022). Least Concern [LC]. EOO = 1,008,132 km2 [LC]; AOO = 468 km2 [EN]. Solanum longifilamentum , since its recognition at the species level, has been shown to have a much wider distribution than originally thought by Särkinen et al. (2015c). Many recent collections exist, indicating that populations are not in decline and, as are most members of the Morelloid clade, S. longifilamentum is a weedy plant of disturbed areas.

Discussion.

Solanum longifilamentum is most similar to S. macrotonum and S. nigrescens of northern South America. It can be distinguished from S. macrotonum by its longer calyx lobes (1-1.5 mm long versus 0.5-0.8(1) mm long) and filaments that are longer relative to the anthers (half the length of the anthers versus always much shorter than the anthers). The styles of S. longifilamentum are exserted to only 0.5-1 mm beyond the anther cone, but styles extend 1.5-3.5 mm beyond the anthers in S. macrotonum . Solanum longifilamentum has consistently narrower, oblong-lanceolate leaves as compared to the more ovate leaves of S. macrotonum . Solanum longifilamentum differs from S. nigrescens in its smaller flowers (0.5-0.6 cm in diameter versus 0.8-1 cm in diameter) with longer anthers (3-3.4 mm long versus 2-2.5 mm long), calyx lobes that are slightly reflexed at the tips at anthesis and strongly reflexed in fruit (versus tightly pressed to the berry in fruit) and its distribution in the Andes of Ecuador, Peru and Bolivia rather than Colombia and Venezuela (extending into Central America, Mexico, the Caribbean and the southern United States of America).

Other species with which S. longifilamentum could be confused include S. americanum and S. pseudoamericanum both of which have smaller anthers (1-1.5 mm long) and S. interandinum that is a larger, broadly spreading shrub up to 2 m high, with larger, violet corollas up to 2 cm in diameter and inflorescence axes that persist long after fruit drop.

Figures

Figure 89. Solanum longifilamentum A flowering and fruiting branch B fruiting branch C stem detail with eglandular multi-cellular trichomes D flower bud E flower at full anthesis F dissected flower G infructescence H fruit I seed (A-I Saerkinen et al. 4585). Illustration by C. Banks.

Figure 90. Solanum longifilamentum A habit B flowers at full anthesis C buds and flowers, floral type without a black central star D fruits with spreading calyx lobes (A Cueva et al. 276 B Saerkinen et al. 4030 C, D Knapp et al. 10545). Photos by S. Knapp, M. Cueva and T. Saerkinen. Previously published in Saerkinen et al. (2015 c: 42).

Figure 91. Distribution map of Solanum longifilamentum.