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

Knapp, Sandra, Barboza, Gloria E., Bohs, Lynn & Saerkinen, Tiina, 2019, A revision of the Morelloid Clade of Solanum L. (Solanaceae) in North and Central America and the Caribbean, PhytoKeys 123, pp. 1-144 : 42-44

3. Solanum corymbosum Jacq., Collectanea [Jacquin] 1: 78. 1787 Figures 9 , 10

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 here: 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 herbs to 30-50 cm tall, subwoody and 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, 4.5-8 cm long, 1.5-4 cm wide, ovate-lanceolate, chartaceous to subcoriaceous; 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 2-3 cm long, lateral, internodal or opposite the leaves, 4-7 times branched, with 20 –50(– 60) flowers spaced along the rhachis, 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, all perfect. 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 5-10 mm 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, hardly exserted from 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, 4-6 mm in diameter, orange to red when ripe, opaque, the surface of the pericarp shiny or matte; fruiting pedicels 2-3 mm long, ca. 0.5 mm in diameter at base, strongly recurved at the very base, dropping with mature fruits, 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 not known.

Distribution.

(Figure 11 ) Solanum corymbosum is native to the western slopes of the Andes in Peru, and naturalised in central and southern Mexico, possibly through introduction in colonial times.

Ecology.

Solanum corymbosum grows in open, disturbed areas in landslides and along roads from 150 to 2,600 m elevation in Mexico (in its presumed native range in Peru from sea level [in coastal lomas vegetation] to 2,900 m elevation).

Common names.

None recorded for the region.

Uses.

None recorded.

Preliminary conservation status ( IUCN 2017).

LC (Least Concern). Solanum corymbosum has a disjunct distribution in Peru and Mexico; in its native range in Peru the species is quite widely distributed, but the AOO for the Mexican plants (76 km2, classing it as EN) combined with potential morphological differences from Peruvian populations (see below) suggests it is of some conservation concern. For EOO see Table 6 .

Discussion.

Solanum corymbosum is a member of the Radicans group and is related to species of southern South America (see Särkinen et al. 2015b). The distribution of this species in Mexico is highly disjunct from what are presumed native populations in Peru and Mexican populations are thought to represent an introduction of this species in post-Columbian times. It is tempting to speculate on an inadvertent introduction between mining areas, perhaps even in Spanish colonial times. Populations in Mexico show nearly identical haplotypes to those from the coastal regions in Peru ( Mitchell 2014), supporting this hypothesis.

Mexican populations of S. corymbosum differ from Andean populations in having larger leaves (20 cm2 Mexico, ca. 9 cm2 Andes) and larger and fewer berries; an average of ca. 30 berries of 5.5 cm diameter per inflorescence in Mexican specimens versus an average of ca. 50 berries of 3.5 mm in diameter per inflorescence in Andean specimens ( Mitchell 2014). This may be due to founder effects in the establishment of the Mexican populations, and Mitchell (2014) has speculated that these populations may be polyploid.

Solanum corymbosum can be distinguished from other morelloids occurring in Mexico in its 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. The leaves are thicker than other morelloids from the area, and the petioles are strongly winged.

Three collections of Solanum corymbosum in BM [all mounted on a single sheet] 1. "Hort. Paris. L’Heritier 1783 (E Peru Dombey)", 2. "Hort. Kew. 1785", 3. "Peru, Dombey 63," P-Lam [Morton neg. 8364] are possible isotype material of various of the synonyms. Collections attributed to Dombey from Paris are probably isolectotype material of S. cymosum (see Knapp 2008b), while those from Kew and the Lamarck herbarium are not type material. It is possible that much of the botanical garden material being described in the late 18th century came from a few collections and is all genetically the same.

Solanum leptanthum is a synonym of S. pubigerum Dunal (a member of the Dulcamaroid clade, Knapp 2013), but variety parviflorum corresponds to S. corymbosum . We have selected the best preserved of the three sheets in the Humboldt and Bonpland herbarium at P (P00670610) as the lectotype for var. parvifolium .

Specimens examined.

See Suppl. materials 1 and 3.

Figures

Figure 9. Solanum corymbosum Jacq. A Habit B detail of adaxial leaf surface C detail of abaxial leaf surface D flowering branch E floral bud F dissected flower G fruiting branch H maturing fruit (A-F van der Werff 14657 G-H Ochoa 14625). Drawing by R. Wise.

Figure 10. Solanum corymbosum Jacq. A Habit B inflorescence C flowers at full anthesis and buds D fully mature red-orange fruits with appressed calyx lobes (A Saerkinen et al. 4604 B B, D Saerkinen et al. 4078; D Saerkinen et al. 4509). Photos by T. Saerkinen.

Figure 11. Distribution of Solanum corymbosum Jacq.