Solanum corymbosum Jacq., Collectanea [Jacquin] 1: 78. 1787.

13. Solanum corymbosum Jacq., Collectanea [Jacquin] 1: 78. 1787. Figs 4B, 41, 42 Solanum corymbiferum J.F.Gmel., Syst. Nat., ed. 13[bis] 2(1): 384. 1791, nom. superfl. illeg. Type. Based on Solanum corymbosum Jacq. (cited in synonymy). Solanum parviflorum Nocca, Ann. Bot. (Usteri) 6: 61.1793, nom. superfl. illeg. Type: Based on Solanum corymbosum Jacq. (cited in synonymy). Solanum parviflorum Salisb., Prodr.Stirp. Chap. Allerton 134. 1796, nom. superfl. illeg. Type. Based on Solanum corymbosum Jacq. (cited in synonymy). Solanum cymosum Ruiz & Pav., Fl. Peruv. [Ruiz & Pavon] 2: 31, t. 160. 1799. Type. Peru. "Habitat in Peruviae cultis, versuris et subhumidis locis per Limae et Chancay Provincias", H. Ruiz & J.A. Pavón s.n. (lectotype, designated by Knapp 2008b, pg. 312: MA [MA-747100]). Solanum corymbosum Jacq. var. cymosum (Ruiz & Pav.) Pers., Syn. Pl. (Persoon) 1: 223. 1805. Type. Based on Solanum cymosum Ruiz & Pav. Solanum leptanthum Dunal var. parvifolium Dunal, Solan. Syn. 9. 1816. Type. Peru. Cajamarca: sin. loc., F.W.H.A. von Humboldt & A. Bonpland s.n. (lectotype, designated by Knapp et al. 2019, pg. 50: P [P00670610]; isolectotypes: P [P00136337, P00136338]). Solanum azureum Van Geert, Cat. Gén. 1879-1880 [Van Geert]: Solanum azureum. 1879. Type. Cultivated in the nursery of Auguste Van Geert in Gand, Belgium, from seeds sent by Mr. Roezl from Peru (no specimens cited; no original material found). Type. Cultivated in Vienna ["Hort. Bot. Vindob."] seeds said to be from Peru, N. von Jacquin s.n. (lectotype, designated by D’Arcy 1970, pg. 559: W [acc. # 0022473]). Description. Annual to short-lived perennial subwoody herbs to 0.5 m high, branching at base. Stems terete, green to straw colour, sprawling, somewhat weak and decumbent, not markedly hollow; new growth nearly glabrous to sparsely pubescent with weak simple, uniseriate appressed 1-8-celled eglandular trichomes, these ca. 0.3 mm long; older stems glabrescent. Sympodial units difoliate or occasionally trifoliate, the leaves not geminate. Leaves simple, the blades 4.5-8 cm long, 1.5-4 cm wide, ovate-lanceolate, widest in the lower third, chartaceous to subcoriaceous, concolorous; both surfaces glabrous or sometimes sparsely ciliate near the base of the winged petiole; major veins 7-9 pairs, not clearly evident abaxially in live plants, paler in herbarium specimens; base long-attenuate, decurrent on the petiole; margins entire (in Peru rarely slightly 3-lobed, Croat 58409); apex acute; petioles 0.5-1 cm, glabrous to sparsely puberulent, winged to the base. Inflorescences internodal or opposite the leaves, 4-7 times branched, 2-3 cm long, with 20-50(-60) flowers spaced along the axis, nearly glabrous to sparsely pubescent; peduncle 0.1-2 cm, straight in fruit; pedicels 2-2.5 mm long, less than 0.5 mm in diameter at the base, ca. 0.5 mm in diameter at the apex, spreading, articulated at the base; pedicel scars spaced 1-3 mm apart. Buds globose, the corolla about halfway exserted from the calyx tube before anthesis, the tips of the corolla lobes often much more pubescent than the calyx. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube 0.5-1 mm long, conical or broadly conical, the lobes 0.5-0.6 mm long, ca. 0.5 mm wide, broadly triangular, glabrous to very sparsely puberulent with simple, uniseriate trichomes. Corolla 0.5-1 cm in diameter, white or purple, the abaxial surface usually purple, rotate-stellate, the lobes 1-2.5 mm long, 1-1.5 mm wide, broadly triangular, reflexed at anthesis, later spreading, glabrous adaxially, minutely white-puberulent abaxially on the tips. Stamens equal; filament tube minute; free portion of the filaments ca. 0.2 mm long, adaxially pubescent with simple tangled white trichomes; anthers 0.8-1.5(-1.8) mm long, ca. 0.5 mm wide, ellipsoid, yellow, somewhat connivent, poricidal at the tips, the pores lengthening to slits with age. Ovary globose, glabrous; style ca. 2 mm long, straight, hardly exserted beyond the anther cone, pubescent in the lower 2/3 with tangled, white uniseriate simple weak-walled trichomes; stigma globose-capitate, minutely papillate, pale green in live plants. Fruit a globose berry, 0.4-0.6 cm in diameter, orange to red when ripe, opaque, the pericarp shiny or matte, translucent, glabrous; fruiting pedicels 0.2-0.3 cm long, ca. 0.5 mm in diameter at base, ca. 0.6 mm in diameter at the apex, strongly recurved at the very base, not persistent; fruiting calyx scarcely accrescent, the tube ca. 1 mm long, the lobes 1-1.3 mm long, appressed to the berry. Seeds 20-30 per berry, 1.5-1.8 mm long, 1.2-1.4 mm wide, flattened reniform with a central hilum, light yellow-tan or reddish brown in herbarium material, the surfaces minutely pitted, the testal cells with sinuate margins. Stone cells 2, ca. 1.5 mm in diameter, globose, prominent near the apex of the berry. Chromosome number: 2n = 24 (Chiarini et al. 2017, voucher Särkinen et al. 4075 ). Distribution (Fig. 43). Solanum corymbosum occurs on the western slopes of the Andes in Peru (Depts. Amazonas, Ancash, Cajamarca, Huánuco, Lambayeque, La Libertad, Lima, Moquegua), and is naturalised in central and southern Mexico, possibly through introduction in colonial times (see discussion in Knapp et al. 2019). Ecology and habitat. Solanum corymbosum grows in open, disturbed areas in landslides and along roads from sea level [in coastal lomas vegetation] to 2,900 m elevation. Common names and uses. Peru. Ancash: cchapchinya (Gómez 51 ); Cusco: ñuñuma, qusmayllu (Roersch 1994, as S. radicans); Huánuco: puslita mullaca (Cárdenas 12275 ); La Libertad: hierba mora (Leiva et al. 707); Lima: hierba mora (Ferreyra 716, Ridoutt 11183a); Puno: chetenguya (Roersch 1994, as. S. radicans). Roersch (1994) records use of leaves in a tea as treatment for sore throats and tonsillitis, macerated leaves as a plaster for swellings, and as a wash for colicky babies and for rheumatism (in combination with other medicinal plants). Although Roersch reports this plant as S. radicans, the illustration (Roersch 1994: 633) and description are clearly S. corymbosum. Preliminary conservation status (IUCN 2022). Least Concern [LC]. EOO = 338,062 km2 [LC]; AOO = 240 km2 [EN]; calculated using South American distribution only. Solanum corymbosum has a disjunct distribution in Peru and Mexico; in its native range in Peru the species is quite widely distributed, but in Mexico potential morphological differences from Peruvian populations suggests it could be of conservation concern in its introduced range (Knapp et al. 2019). In Peru it occurs in several protected areas (e.g., Reserva Nacional Calipuy and the lower elevations of Parque Nacional Huascarán). Discussion. Solanum corymbosum is a member of the Radicans group (Särkinen et al. 2015b) and has an unusual disjunct distribution in Peru and Mexico; Mexican populations are thought to represent an introduction of this species in post-Columbian times (Knapp et al. 2019). Populations in Mexico show nearly identical haplotypes to those from the coastal regions in Peru (Mitchell 2014), supporting this hypothesis. Solanum corymbosum can be distinguished from other members of the Radicans group in its simple, entire leaves, small orange to red fruits with two large apical stone cells, its highly branched inflorescences and diminutive flowers with rotate-stellate corollas that are usually white adaxially and purple abaxially. Other members of the group have 3- to 5-lobed leaves (e.g., S. palitans, S. radicans, S. tripartitum), although a population of S. tripartitum from the Province of Salta, Argentina appears to be uniformly simple-leaved. Corolla size of S. corymbosum overlaps with these plants at its upper range, but flowers of S. corymbosum are generally smaller (0.5-1 cm in diameter) than those of S. tripartitum (0.9-1.1 cm in diameter), and S. tripartitum has more than two stone cells per berry. The two species are not sympatric.Published as part of Knapp, Sandra, Saerkinen, Tiina & Barboza, Gloria E., 2023, A revision of the South American species of the Morelloid clade (Solanum L., Solanaceae), pp. 1-342 in PhytoKeys 231 on page 1, DOI: 10.3897/phytokeys.231.10089