Solanum pseudoamericanum Saerkinen , P. Gonzales & S.Knapp, PhytoKeys 31: 10. 2013.

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

44. Solanum pseudoamericanum Saerkinen, P. Gonzales & S.Knapp, PhytoKeys 31: 10. 2013.

Figs 134 , 135

Type.

Peru. Cajamarca: Prov. Cajabamba, in town of Cajabamba , 7°36'43"S, 78°03'28"W, 2,649 m, 9 May 2013, S. Knapp, T. Särkinen, H.M. Baden, P. Gonzáles & E. Perales 10575 (holotype USM; isotypes BM [BM001120840], CORD [CORD00006824], CPUN, E [E00700636], HUT) .

Description.

Herb with woody base, 0.2-0.6 m high, the individual stems to 1 m long and sprawling. Stems terete or somewhat angled with ridges, pubescent with simple, uniseriate 1-4-celled trichomes, these often clustered along the stem angles; new growth densely pubescent with appressed 1-4-celled simple, uniseriate trichomes 0.2-0.8 mm long. Sympodial units difoliate, not geminate. Leaves simple and shallowly toothed, the blades 4.5-12(-15) cm long, 1.8-8 cm wide, ovate to elliptic, widest near or just below the middle, membranous, somewhat discolorous; adaxial surface sparsely pubescent with more or less appressed 1-4-celled translucent simple, uniseriate trichomes, these denser along the veins; abaxial surface more densely pubescent with simple uniseriate trichomes like those of the upper surface; principal veins 5-8 pairs; base acute and decurrent on the petiole; margins entire or occasionally with shallow lobes in the basal third; apex acute; petiole 0.5-2.5(-5) cm long, occasionally narrowly winged, sparsely pubescent with simple uniseriate trichomes like those of the stems and leaves. Inflorescences internodal, unbranched or forked, 1-2.5 cm long, with 3-5(9) flowers, sparsely pubescent with appressed 1-2-celled simple uniseriate trichomes; peduncle 0.4-1.6 cm long, if the inflorescence branched, then the peduncle of each branch 0.4-0.6 cm long; pedicels 0.6-0.7 cm long, ca. 0.3 mm in diameter at the base and apex, straight and spreading, articulated at the base; pedicel scars spaced ca. 1 mm apart. Buds globose, the corolla only exserted from the calyx tube just before anthesis. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube ca. 1 mm long, the lobes 0.5-0.7 mm long with rounded apices, sparsely pubescent with 1-4-celled translucent simple uniseriate trichomes. Corolla 0.5-0.6 cm in diameter, stellate, white with a yellow central portion near the base, lobed slightly less than halfway to the base, the lobes ca. 1.5 mm long, 2 mm wide, strongly reflexed at anthesis, later spreading, densely pubescent abaxially with 1-4-celled simple uniseriate trichomes, these usually shorter than the trichomes of the stems and leaves. Stamens equal; filament tube minute, pubescent with tangled uniseriate trichomes adaxially; free portion of the filaments ca. 1 mm long, pubescent like the tube; anthers 1-1.5 mm long, 0.7-0.8 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age. Ovary conical, glabrous; style 3-4 mm long, straight, somewhat long-exserted beyond the anther cone, densely pubescent with 2-3-celled simple uniseriate trichomes at the base; stigma globose and capitate, minutely papillate, bright green in live plants. Fruit a globose berry, 0.4-0.9 cm in diameter, green at maturity or green and turning purplish black when ripe, the pericarp not markedly shiny, opaque, glabrous; fruiting pedicels 0.4-0.7 cm long, ca. 1 mm in diameter at the base, ca. 1.2 mm in diameter at the apex, spreading and becoming somewhat more woody in fruit, persistent and usually remaining on the plant after fruit drops; fruiting calyx lobes spreading or appressed to the berry, not reflexed. Seeds 35-45 per berry, 1.2-1.5 mm long, 0.9-1 mm wide, flattened-reniform, yellowish straw-coloured, the surfaces minutely pitted, the testal cells pentagonal in outline. Stone cells absent. Chromosome number: not known.

Distribution

(Fig. 136 ). Solanum pseudoamericanum occurs from southern Ecuador (Prov. Imbabura), throughout Andean Peru (Depts. Amazonas, Ancash, Apurímac, Ayacucho, Cajamarca, Cusco, Huánuco, La Libertad, Lima, Pasco, Piura) to northern Bolivia (Dept. La Paz).

Ecology and habitat.

Solanum pseudoamericanum grows in the upper zones of seasonally dry tropical forests to mid-elevation montane forests, commonly growing in sandy soils in full sun or partial shade in disturbed sites such as landslides and roadsides or cultivated areas, often in moist depressions in otherwise dry areas, from (930-)1,700 to 3,200(-3,735) m in elevation. A single anonymous collection recorded as occurring at 100 m elevation in the Department of Lima may be a label error.

Common names and uses.

Peru. Ancash: atoqpa papan (Gamarra 416); Amazonas: hierba mora ( García Llatas 8155); Lima: hierba mora (Vilcapoma 1649a, 5330). No uses recorded.

Preliminary conservation status

( IUCN 2022). Least Concern [LC]. EOO = 668,293 km2 [LC]; AOO = 180 km2 [EN]. Solanum pseudoamericanum , previously unrecognised as distinct from the widespread S. americanum , has been collected more often since its description, increasing the range and number of populations greatly. Solanum pseudoamericanum occurs in at least one protected area in Peru (e.g., Lomas de Lachay).

Discussion.

Solanum pseudoamericanum can be distinguished from the similar S. americanum by the following suite of characters; berries that are matte or somewhat shiny at maturity, versus very shiny in S. americanum , styles that are always exserted to approximately equal to the length of the anther cone, versus styles almost included in the anther cone in S. americanum and the globose, bright green stigmas, versus a white or pale green stigmas that are merely a widening of the style tip in S. americanum . Solanum pseudoamericanum usually occurs above 2,000 m elevation, with only some overlap between the closely related S. americanum that occurs from sea level to 2,200 m in elevation.

Other members of the Morelloid clade in Peru without glandular trichomes which grow sympatrically with S. pseudoamericanum differ from it in being larger in growth form (reaching up to 2 m in height), having larger, violet flowers and fruits that are green at maturity ( S. cochabambense , S. interandinum ), or being smaller herbs up to 30 cm high with similarly sized flowers but red, orange or yellow berries ( S. corymbosum , S. palitans , S. radicans ). Solanum longifilamentum is somewhat similar to S. pseudoamericanum but has longer anthers (2-3.4 mm long versus 1-1.5 mm long) and more ellipsoid buds.

Figures

Figure 134. Solanum pseudoamericanum A flowering and fruiting habit B detail of adaxial leaf surface C detail of abaxial leaf surface D flower bud E dissected flower F fruit (A-F Knapp et al. 10300, Knapp et al. 10351). Illustration by R. Wise. Previously published in Saerkinen et al. (2013: 13).

Figure 135. Solanum pseudoamericanum A habit B ridged stem C inflorescence with buds and flowers at full anthesis D maturing fruits (A Saerkinen et al. 4640 B Knapp et al. 10357 C, D Knapp et al. 10300). Photos by S. Knapp and T. Saerkinen. Previously published in Saerkinen et al. (2013: 15).

Figure 136. Distribution map of Solanum pseudoamericanum.