Solanum americanum Mill., Gard. Dict. ed. 8, no. 5. 1768.

Saerkinen, Tiina, Poczai, Peter, Barboza, Gloria E., Weerden, Gerard M. van der, Baden, Maria & Knapp, Sandra, 2018, A revision of the Old World Black Nightshades (Morelloid clade of Solanum L., Solanaceae), PhytoKeys 106, pp. 1-223 : 1

2. Solanum americanum Mill., Gard. Dict. ed. 8, no. 5. 1768. Figures 7 , 8

Solanum nigrum L. var. patulum L., Sp. Pl. 186. 1753.

Solanum americanum Type. "Solanum procerius patulum, vulgaris fructu", cultivated in England, at James Sherard’s garden in Eltham (Hortus Elthamensis) (lectotype, designated here: Dillenius, Hortus Elthamensis 2: 367, t. 275, f. 355. 1732). "Solanum procerius patulum, vulgaris fructu", Herb. Dillenius 441 (epitype, designated here [as lectotype by Edmonds 2012, pg. 136]: OXF [Dill-HE 275-355).

Solanum nodiflorum Jacq., Collectanea [Jacquin] 2: 288. 1789.

Solanum americanum Type. Cultivated in Austria at Vienna, said to be from Mauritius ("crescit insula Mauritii"), Herb. Jacquin s.n. (lectotype, designated by Henderson 1974, pg. 28: BM [BM000617682]; isolectotype: W [W0022646]).

Solanum patulum (L.) Roth, Catal. Bot. 2: 23. 1800.

Solanum americanum Type. Based on Solanum nigrum L. var. patulum L.

Solanum papilionaceum Dum.Cours., Bot. Cult. 2: 135. 1802.

Solanum americanum Type. Cultivated from seeds received from the Jardin Nat. [Paris] (no specimens cited, likely to have been described from living material). Cultivated in Paris ( “H.P.”), 1825, Anon. [Herb. Maire] s.n. (neotype, designated here: P [P00582223]).

Solanum strictum Zuccagni, Cent. Observ. Bot. [p. 20] No. 49. 1806.

Solanum americanum Type. Cultivated in Italy; "Semina nobis communicavit Cl. Thouin sub nomine S. nigri sp. nova" (no specimens cited; Zuccagni’s herbarium originally at FI but destroyed). Cultivated in Italy in Bologna "j. de Bologna", 6 Jul 1808, Anon. s.n. (neotype, designated here: G-DC [G00144215]).

Solanum rumphii Dunal, Hist. Nat. Solanum 157. 1813.

Solanum americanum Type. Indonesia. Malaku: Amboina (no specimens cited; lectotype, designated here: Rumphius, Herbarium Amboinenese 6: t. 26, fig. 2, 1750).

Solanum oleraceum Dunal, Encycl. [J. Lamarck & al.] Suppl. 3: 750. 1814.

Solanum americanum Type. “Antilles” Herb, Richard s.n. (lectotype, designated by D’Arcy 1974a, pg. 735: P [P00319557]; isolectotypes: G-DC [G00144258], MPU).

Solanum dillenii Schult., Öster. Fl., ed. 2, 1: 393. 1814, as " Dilleni "

Solanum americanum Type. Hungary?. "In umbrosis Matra [ Mátra]”, P. Kitaibel s.n. (lectotype, designated here: BP [Herb. Kit. fasc. IX, No. 102, small-flowered stem only]; isolectotype: B-W [B-W 04364-03]).

Solanum microspermum Dunal, Solan. Syn. 12. 1816.

Solanum americanum Type. Origin unknown, 1815, Anon. (Herb. Thibaud) s.n. (lectotype, designated here: G-DC [G00144267]).

Solanum erythrocarpon G.Mey., Prim. Fl. Esseq. 109. 1818.

Solanum americanum Type. Suriname. Saramacca: Hamburg (Essequibo), E.K. Rodschied 31 (lectotype, designated here: GOET [GOET003505]).

Solanum desvauxii Ham., Prod. Pl. Ind. Occ. 26. 1825, nom. illeg. superfl.

Solanum americanum Type. Based on S. nodiflorum Jacq. (cited in synonymy).

Solanum nigrum Vell., Fl. Flumin. 85. 1829 [1825], nom. illeg., not Solanum nigrum L. (1753)

Solanum americanum Type. Brazil. [Rio de Janeiro]: "undequaeque nascitur" (lectotype, designated by Knapp et al. 2015, pg. 832: [illustration] Original parchment plate of Flora Fluminensis in the Manuscript Section of the Biblioteca Nacional, Rio de Janeiro [cat. no.: mss1198651_112] and later published in Vellozo, Fl. Flumin. Icon. 2: tab. 109. 1831).

Solanum tenuiflorum Steud., Nomencl. ed. 2, 2: 606. 1841.

Solanum americanum Type. Based on (replacement name for) Solanum nigrum Vell.

Solanum indecorum A.Rich., Hist. Fls. Cuba, Fanerogamia 11: 121. 1841.

Solanum americanum Type. Cuba. Sin loc., 1836, R. de la Sagra s.n. (lectotype, designated here: P [P00370899]).

Solanum nigrum L. subsp. nodiflorum (Jacq.) Sendtn., Fl. Bras. (Martius) 10: 16. 1846.

Solanum americanum Type. Based on Solanum nodiflorum Jacq.

Solanum nigrum L. var. angulosum Sendtn., Fl. Bras. (Martius) 10: 16. 1846, as Solanum nigrum L. subsp. nodiflorum (Jacq.) Sendtn. var. angulosum Sendtn.

Solanum americanum Type. Based on Solanum tenuiflorum Steud. (= Solanum nigrum Vell.)

Solanum nigrum L. subsp. aguaraquiya Sendtn., Fl. Bras. (Martius) 10: 17. 1846.

Solanum americanum Type. Brazil. Rio Grande do Sul: "Pat. Joan a St. Barbara", C.F.P. Martius s.n. (lectotype, designated here: M [M-0171809]; isolectotype: M [M-0171810]).

Solanum nigrum L. var. minus Hook.f., Trans. Linn. Soc. London 20(2): 201. 1847, as " minor "

Solanum americanum Type. Ecuador. Galápagos Islands: James Island [Santiago], C. Darwin s.n. (lectotype, designated here: CGE [CGE00297]; isolectotype: K [K000922162]).

Solanum amarantoides Dunal, Prodr. [A. P. de Candolle] 13(1): 55. 1852.

Solanum americanum Type. Brazil. Rio de Janeiro, C. Gaudichaud 522 (lectotype, designated by D’Arcy 1974a, pg. 735 [as holotype]; second step designated here: P [P00319574]; isolectotypes: P [P00319575], MPU).

Solanum pterocaulum Dunal var. aguaraquiya (Sendtn.) Dunal, Prodr. [A. P. de Candolle] 13(1): 52. 1852, as ' Solanum pterocaulon '.

Solanum americanum Type. Based on Solanum nigrum L. subsp. aguaraquiya Sendtn.

Solanum ptychanthum Dunal, Prodr. [A. P. de Candolle] 13(1): 54. 1852.

Solanum americanum Type. United States of America. Georgia: Chatham Co., Savannah, Anon. s.n. (holotype: G-DC [G00144485]).

Solanum nodiflorum Jacq. var. macrophyllum Dunal, Prodr. [A. P. de Candolle] 13(1): 46. 1852.

Solanum americanum Type. Brazil. Rio de Janeiro: Rio de Janeiro, C. Gaudichaud 521 (lectotype, designated by D’Arcy 1974a, pg. 735: P [P00319582]; isolectotypes: P [P00319583, P00319585], G-DC [G00144100], G [G00343373]).

Solanum nodiflorum Jacq. var. acuminatum Dunal, Prodr. [A. P. de Candolle] 13(1): 46. 1852.

Solanum americanum Type. Brazil. Minas Gerais: Sin loc., M. Vauthier 537 (lectotype, designated by D’Arcy 1974a, pg. 735 [as type ex Herb. Drake]: P [P00319615]; isolectotypes: P [P00319614], G-DC [G00343360]).

Solanum nodiflorum Jacq. var. petiolastrum Dunal, Prodr. [A. P. de Candolle] 13(1): 46. 1852.

Solanum americanum Type. Brazil. Rio de Janeiro: Novo Friburgo, 1842, P. Claussen 180 (holotype: P [P00319584]).

Solanum inops Dunal, Prodr. [A. P. de Candolle] 13(1): 55. 1852.

Solanum americanum Type. Mexico. "sin. loc." [Tamaulipas: Tampico, 4 Feb 1827], J.L. Berlandier 46 (holotype: G-DC [G00144469]; isotypes: BM [BM000775579], F [V0073104F, acc. # 680275], LE, P [P00336046, P00336047, P00336048], W [1889-0291394, 1889-0144848]).

Solanum nigrum L. forma nodiflorum (Jacq.) Miq., Fl. Ned. Ind. 2: 637. 1856.

Solanum americanum Type. Based on Solanum nodiflorum Jacq.

Solanum nigrum L. forma rumphii (Dunal) Miq., Fl. Ned. Ind. 2: 637. 1856.

Solanum americanum Type. Based on Solanum rumphii Dunal

Solanum nigrum L. forma nodiflorum (Jacq.) Miq., Fl. Ned. Ind. 2: 637. 1856.

Solanum americanum Type. Based on Solanum nodiflorum Jacq.

Solanum nigrum L. forma uniflorum Miq., Fl. Ned. Ind. 2: 638. 1856.

Solanum americanum Type. Indonesia. Java: "op den Diëng, 6000-8000 ft", F.W. Junghuhn s.n. (lectotype, designated here: U [U0113977]).

Solanum patulum Kit. ex Kanitz, Linnaea 32: 440. 1863, nom illeg., not Solanum patulum (L.) Roth (1800).

Solanum americanum Type. Based on Solanum dillenii Schult. (cited in synonymy)

Solanum nigrum L. subsp. dillenii (Schult.) Schur, Enum. Pl. Transsilv. 478. 1866.

Solanum americanum Type. Based on Solanum dillenii Schult.

Solanum nigrum L. var. dillenii (Schult.) A.Gray, Synopt. Fl. N. Amer. 2(1): 228. 1878.

Solanum americanum Type. Based on Solanum dillenii Schult.

Solanum nigrum L. var. nodiflorum (Jacq.) A.Gray, Synopt. Fl. N. Amer 2(1): 228. 1878.

Solanum americanum Type. Based on Solanum nodiflorum Jacq.

Solanum nigrum L. var. oleraceum (Dunal) Hitchc., Rep. Missouri Bot. Gard 4: 111. 1893.

Solanum americanum Type. Based on Solanum oleraceum Dunal

Solanum nigrum L. var. nodiflorum (Jacq.) Hitchc., Rep. (Annual) Missouri Bot. Gard. 4: 111. 1893, nom. illeg., not Solanum nigrum L. var. nodiflorum (Jacq.) A. Gray (1878)

Solanum americanum Type. Based on Solanum nodiflorum Jacq.

Solanum nigrum L. var. americanum (Mill.) O.E.Schulz, Symb. Antill. (Urban) 6: 160. 1909.

Solanum americanum Type. Based on Solanum americanum Mill.

Solanum nigrum L. forma grandifolium O.E.Schulz, Symb. Antill. (Urban) 6: 160. 1909, as Solanum nigrum L. var. americanum (Mill.) O.E.Schulz forma grandifolia O.E.Schulz

Solanum americanum Type. Puerto Rico. "prope Cayey in sylvis ad rivulum superiorem m. Sept. fl. et. fr.", P.E.E. Sintenis 2429 (probably type, no herbarium cited).

Solanum nigrum L. forma parvifolium O.E.Schulz, Symb. Antill. (Urban) 6: 160. 1909, as Solanum nigrum L, var. americanum (Mill.) O.E.Schulz forma parvifolia O.E.Schulz.

Solanum americanum Type. Cuba. La Habana: Santiago de las Vegas, " Baker Herb. Cub. 3377 " (probably type, no herbarium cited).

Solanum minutibaccatum Bitter, Repert. Spec. Nov. Regni Veg. 10: 549. 1912.

Solanum americanum Type. Bolivia. La Paz: San Carlos, bei Mapiri, 750 m, Aug 1907, O. Buchtien 1443 (lectotype, designated here: US [00027684, acc. # 1175843]; isotypes: GOET [GOET003478], NY [00172089]).

Solanum inconspicuum Bitter, Repert. Spec. Nov. Regni Veg. 11: 204. 1912.

Solanum americanum Type. Peru. Lima: Lima, 12 Jul 1910, C. Seler 222 (holotype: B, destroyed; no duplicates found).

Solanum tenellum Bitter, Repert. Spec. Nov. Regni Veg. 11: 219. 1912.

Solanum americanum Type. Brasil. Minas Gerais: "Prope urbem Caldas florens fructibusque instructum", 4 Oct 1869, A.F. Regnell III 970 (holotype: UPS; isotypes: US [00027821, acc. # 201069, 01931849, acc. # 201352]).

Solanum minutibaccatum Bitter subsp. curtipedunculatum Bitter, Repert. Spec. Nov. Regni Veg. 11: 205. 1912.

Solanum americanum Type. Bolivia. La Paz: Guanai-Tipuani, Apr-Jun 1892, M. Bang 1462 (holotype: W; isotypes: BM [BM000617672], E [E00106087], M [M-0171808], MO [MO-503647], NDG [NDG42278], NY [00172090, 00172091, 00172092], PH [PH00030453], US [00027685, acc. # 1324656], WIS [0256198WIS]).

Solanum sciaphilum Bitter, Repert. Spec. Nov. Regni Veg. 11: 220. 1912.

Solanum americanum Type. Brazil. Santa Catarina: Pedras Grandes, Aug 1890, E. Ule 1678 (holotype: B, destroyed, F neg. 2851; lectotype, designated here: HBG [HBG-511539]; isolectotype: HBG [HBG-511540]).

Solanum curtipes Bitter, Repert. Spec. Nov. Regni Veg. 11: 228. 1912.

Solanum americanum Type. Paraguay. Cordillera: San Bernardino, Aug 1898-1899, É. Hassler 3104 (holotype: B, destroyed; lectotype, designated by Morton 1976, pg. 149; second step designated here: G [G00306710]; isolectotypes: G [G00306711, G00306712, G00306713, G00306714], K [K000532497], P [P00325762], NY [00139112], UC [UC950837]).

Solanum calvum Bitter, Repert. Spec. Nov. Regni Veg. 12: 81. 1913.

Solanum americanum Type. Mexico. Baja California: Guadalupe Island, 1875, E. Palmer 60 [pro parte] (holotype: UPS; isotypes: BM [BM001017192], MO [MO-159620, MO-568722], NY [00138967, 00759880], YU [YU065319]).

Solanum depilatum Bitter, Repert. Spec. Nov. Regni Veg. 12: 88. 1913.

Solanum americanum Type. Madagascar. Toliara: Fort Dauphin [anchorage], 1897, G. Paroisse 10 (holotype: P [P00338747]).

Solanum imerinense Bitter, Bot. Jahrb. Syst. 49: 566. 1913.

Solanum americanum Type. Madagascar. Antananarivo: "Central Madagaskar, Imerina", Dec 1880, J.M. Hildebrandt 3796 (lectotype, designated by Edmonds 2012, pg. 136: M [M-0105626]; isolectotypes: CORD [CORD00006927], P [P00338727, P00338738], BM [BM000887188]).

Solanum sancti-thomae Bitter, Bot. Jahrb. Syst. 49: 560. 1913, as " Sancti Thomae "

Solanum americanum Type. São Tome and Principe: São Tome, F. Quintas & A. Moller 47 (syntypes: B, destroyed, COI, not located).

Solanum nodiflorum Jacq. var. sapucayense Chodat, Bull. Soc. Bot. Genève, sér. 2, 8: 150. 1916.

Solanum americanum Type. Paraguay. Paraguarí: Sapucaí [ “Sapucay”], 1914, R. Chodat & W. Vischer 46 (holotype: G [G00306708]).

Solanum nigrum L. subsp. dillenii (Schult.) Probst, Mitteil. Naturfor. Gesellsch. Solothurn 9: 33. 1932.

Solanum americanum Type. Based on Solanum dillenii Schult.

Solanum nigrum L. var. pauciflorum Liou, Contr. Inst. Bot. Natl. Acad. Peiping 3: 454. 1935.

Solanum americanum Type. China. Hainan: Ngai District, Yeung Ling Shan, 5 Jun 1932, S.K. Lau 209 (lectotype, designated here: BM [BM000942311]; isolectotypes: A, LU?, K [K001152446]).

Solanum merrillianum Liou, Contr. Inst. Bot. Nat. Acad. Peiping 3: 455. 1935.

Solanum americanum Type. China. Hainan: Thai Hang, Shek Kuet Ts’o, Lin Fa Shan and vicinity, Lam Ko District, W.T. Tsang 412 (holotype: LU [acc. no. 15911, not seen]; isotypes: A [A00077824, A00395157], E [E00718800], MO [acc. # 1037660], S [acc. # S-G-5703]).

Solanum photeinocarpum Nakam. & Odash., J. Soc. Trop. Agric., Taiwan 8: 54. 1936.

Solanum americanum Type. Taiwan. “Taihoku” [Taipei?], 28 Feb 1936, K. Odashima 17720 (lectotype, designated here: TAI).

Solanum pachystylum Polg., Trans.& Proc. Roy. Soc. N. Z. 69: 280. 1940.

Solanum americanum Type. New Zealand. North Island: Auckland, Mt. Wellington, near Auckland, Plant Research Station, H.H. Allan s.n. (holotype: CHR [8954]; isotypes: CHR [8954 A], CHR [8954 B]).

Solanum americanum Mill. var. nodiflorum (Jacq.) Edmonds, J. Arnold Arb. 52: 634. 1971.

Solanum americanum Type. Based on Solanum nodiflorum Jacq.

Solanum suffruticosum Schousb. ex Lange var. merrillianum (Liou) C.Y.Wu & S.C.Huang, Fl. Hainan. 3: 586. 1974.

Solanum americanum Type. Based on Solanum merrillianum Liou

Solanum nodiflorum Jacq. subsp. nutans R.J.F.Hend., Contr. Queensland Herb. 16: 30. 1974.

Solanum americanum Type. Australia. Queensland: Brisbane, Dept. Primary, Industrial grounds, 3 Jul 1969, R.J.F. Henderson 518 (holotype: BRI [AQ0023172]; isotypes K [K001080528], NSW [NSW568939], MEL [MEL2289999A]).

Solanum americanum Mill. var. patulum (L.) Edmonds, Bot. J. Linn. Soc. 75: 171. 1977.

Solanum americanum Type. Based on Solanum nigrum L. var. patulum L.

Solanum americanum Mill. subsp. nodiflorum (Jacq.) R.J.F.Hend., Austrobaileya 2: 555. 1988.

Solanum americanum Type. Based on Solanum nodiflorum Jacq.

Solanum pauciflorum (Liou) H.Y.Zhang, Bull. Bot. Res., Harbin 19(2): 131. 1999.

Solanum americanum Type. Based on Solanum nigrum L. var. pauciflorum Liou

Type.

Cultivated at the Chelsea Physic Garden [in protologue said to "grow naturally in Virginia"], Herb. Miller s.n. (lectotype, designated by Edmonds 1972, pg. 103 [as type]: BM [BM000617683]).

Description.

Annual to short-lived erect or weakly scrambling perennial herbs up to 1.5 m tall, subwoody and branching at base. Stems spreading, terete or somewhat angled with ridges, green to somewhat purple tinged, older stems often appearing spinescent, not markedly hollow; new growth pubescent with simple, spreading, uniseriate, translucent, eglandular trichomes, these 2-8-celled, 0.2-0.8 mm long, often clustered along the stem angles; older stems glabrescent, with only the trichome bases persisting as pseudo-spines. Sympodial units difoliate, the leaves not geminate. Leaves simple, 3.5-10.5 cm long, 1.0-4.5 cm wide, ovate to elliptic, membraneous, concolorous, without odour; adaxial surface sparsely pubescent with simple, uniseriate trichomes like those on stem, these evenly spread along the lamina and the veins; abaxial surface similar but more densely pubescent; major veins 3-6 pairs; base attenuate, decurrent on the petiole; margins entire or occasionally sinuate-dentate; apex acute; petioles (0.3-)2.0-3.8(-4.0) cm long, sparsely pubescent with simple uniseriate trichomes like those on stems. Inflorescences 0.6-2.5 cm long, internodal, simple or very rarely furcate, umbelliform to sub-umbelliform, with (3-)4-6(-8) flowers (very rarely with more flowers in branched inflorescences), sparsely pubescent with simple uniseriate trichomes like those on stems; peduncle (0.5-)1.0-1.8 cm long, straight and stout; pedicels 3-9 mm long, 0.2-0.3 mm in diameter at the base and 0.4-0.5 mm at the apex, stout, straight and spreading, articulated at the base; pedicel scars spaced 0-0.5 mm apart, clustered at the tip of the inflorescence. Buds broadly ellipsoid, the corolla 1 exserted/3 beyond the calyx lobe tips before anthesis. Flowers 5-merous, all perfect. Calyx tube 0.8-1.3 mm long, conical, the lobes 0.3-0.5 mm long, 0.5-0.6 mm wide, broadly triangular, the tips obtuse, sparsely pubescent with simple uniseriate trichomes like those of the stem. Corolla 3-6 mm in diameter, white with a yellow-green central portion near the base, stellate, lobed 1/2-2/3 of the way to the base, the lobes 2.0-3.2 mm long, 1.0-2.5 mm wide, strongly reflexed at anthesis, later spreading, densely papillate abaxially with 1-4-celled simple uniseriate trichomes, these denser on the tips and margins. Stamens equal; filament tube minute; free portion of the filaments 0.5-0.8 mm long, adaxially pubescent with tangled uniseriate trichomes; anthers 0.8-1.5 mm long, 0.5-0.6 mm wide, ellipsoid to almost globose, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary globose, glabrous; style 2.2-2.6 mm long, densely pubescent with 2-3-celled simple uniseriate trichomes in the lower 2/3 where included in the anther cone, almost included to exserted 0.5(-1.0) mm beyond the anther cone; stigma minutely capitate, the surface minutely papillate, green in live plants. Fruit a globose berry, 4-9(-12) mm in diameter, purplish-black at maturity, the pericarp thin and markedly shiny; fruiting pedicels 13-18 mm long, 0.7-1.0 mm in diameter at the base and 0.8-1.0 mm at apex, stout, straight and spreading, spaced 0-0.5 mm apart, not falling with the fruit, remaining on the plant and persistent on older inflorescences; fruiting calyx not accrescent, the tube less than 1 mm long, the lobes 1(-2) mm long, strongly reflexed at fruit maturity. Seeds 30-50 per berry, 1.0-1.5 mm long, 0.8-1.3 mm wide, flattened and tear-drop shaped with a subapical hilum, pale yellow, the surfaces minutely pitted, the testal cells pentagonal in outline. Stone cells mostly absent (Australia, South Pacific and South America), but if present (North America, Mexico, Eurasia and Africa) 2-4(6) per berry, 2-4 larger ones>0.5 mm and two smaller ones <0.5 mm in diameter. Chromosome number: 2n =2x=24 ( Tokunaga 1933 [as S. dillenii ]; Nakamura 1937 [as S. photeinocarpum ]; Stebbins and Paddock 1949 [as S. nodiflorum ]; Heiser 1955 under S. nodiflorum ; Baylis 1958 as S. nodiflorum ; Soria and Heiser 1961 [as S. nodiflorum ]; Heiser et al. 1965 [as S. nodiflorum ]; Edmonds 1972, 1977, 1982, 1983, 1984a; Venkateswarlu and Rao 1972 [vouchers labelled as S. nigrum S14, S30, S31]; D’Arcy 1974a; Henderson 1974; Tandon 1974; Bhiravamurty 1975 [as S. nodiflorum ]; Randell and Symon 1976; Symon 1981; Ganapathi and Rao 1986a; Symon 1985; Schilling and Andersen 1990; Bukenya 1996; Jacoby and Labuschagne 2006; Moyetta et al. 2013; Olet et al. 2015).

Distribution

(Figure 9 ). Globally distributed weed found across tropical and subtropical areas; probably native to the Americas, but there is little evidence for its origin or introduction.

Ecology.

Grows in disturbed habitats and associated with human activities in tropical moist to dry areas, in dry areas often found growing in full shade close to water sources; between sea level and 2,000 (-2,500) m elevation.

Common names.

American Samoa: magalo; Australia: glossy nightshade ( Symon 1981); Benin: odu, ogomo, feibii ( Essou and Hermans 2006); China: shao hua long kui, guang zhi mu long kui (as S. merrillianum ) ( Zhang et al. 1994); Finland: amerikanmustakoiso ( Hämet-Ahti et al. 1998); Ghana: ebibirba; Indonesia. booso, doehet ratti, lohoet/lohoetoe [lohoetoe-lohoetoe] ranti; Kenya: mnairi; Madagascar: anamama; Malaysia: beliwan, lutan, ranti, tutan, tutan-toposi; Mauritius: brede martin; New Zealand: small-flowered nightshade ( Webb et al. 1988); Nigeria: odú; Niue: plo fua, polo kai; Norfolk Island: ang’adsindra, bwamunovi; Papua New Guinea: tuskombuk; Philippines: amti niitang [Ifugao people], onti; South Africa: black nightshade; Sri Lanka: kalu kamberiya; Sweden: Amerikansk nattskatta ( Mossberg et al. 2003); Tanzania: imbenek, mavu, mnafu, mnaru, mwihakhi; Tonga: polo kai, polo tonga; Uganda: ocuga; United States of America[Hawaii]: popolo, popolohua; Vanuatu: ne poro, poro.

Uses.

In all parts of its range, the leaves of S. americanum are used as spinach and the ripe berries are eaten, either raw or cooked.

Preliminary conservation status

( IUCN 2016). Solanum americanum is an extremely widespread cosmopolitan weed and can be assessed as LC (Least Concern; Table 7 ).

Discussion.

Solanum americanum is a diploid species that can be easily recognised by its shiny black fruits on spreading pedicels with strongly reflexed calyx lobes (to parallel with the pedicel) that are somewhat papillate abaxially. In fruit, the pedicels remain on the plant after fruits fully mature and drop off, leaving behind a distinct group of tightly clustered spreading pedicels with reflexed calyx lobes; this character is easily visible in many herbarium specimens. In flower, S. americanum has tiny, almost globose anthers 0.8-1.5 mm long borne on short filaments. It can be distinguished from S. opacum , which also has tiny anthers of the same size, in its shorter filaments relative to anther size and in its deltate calyx lobes with rounded tips. Solanum opacum has longer filaments relative to anther size, long-triangular calyx lobes and, in fruit, the calyx lobes are appressed to the base of the berry. Three other morelloids with such small anthers can be difficult to distinguish from S. americanum and are often confused with it in herbaria. Solanum emulans Raf. does not occur in the Old World (except sometimes in old botanical garden collections, see discussion of the typification of S. patulum and S. dillenii below; it is a species of the north-eastern United States and Canada) has matte berries and longer calyx lobes. Solanum nitidibaccatum also has extremely small anthers, but can be easily distinguished by its glandular pubescence and accrescent calyx in fruit. Solanum opacum is the third morelloid with tiny anthers and the most difficult to distinguish from S. americanum in the Old World. Solanum americanum and S. opacum co-occur across the Pacific and distinguishing individual specimens can be difficult, but the shiny fruits (versus matte in S. opacum ) and persistent pedicels with strongly reflexed calyx lobes are good characters by which to recognise S. americanum .

In southeast Asia and China, S. americanum is at least partially sympatric with S. nigrum (see discussion of S. nigrum ). The species can be distinguished by anther size (0.8-1.5 mm versus ca. 2-2.5 mm) and by inflorescence morphology; S. americanum usually has few flowers that are tightly congested in the distal part of the inflorescence, while S. nigrum usually has more flowers that are more spaced out along the inflorescence rhachis, although young inflorescences of S. nigrum can appear sub-umbellate. In fruit, the strongly reflexed calyx lobes of S. americanum are distinctive and the seeds are smaller than those of the hexaploid S. nigrum (ca. 1 mm versus ca. 2 mm long).

Solanum merrillianum was recognised as a distinct species in the Flora of China ( Zhang et al. 1994), but variation described fits within the observed variation of S. americanum after studies of the species across its global range. Specimens described as S. merrillianum show branching inflorescences in some individuals with generally larger number of flowers per inflorescence than seen in S. americanum , but the larger inflorescences may be due to pre-domestication and/or selection of the species in China and Taiwan, where fruits of S. americanum are commonly eaten.

Solanum americanum exhibits the highest infraspecific genetic diversity compared to polyploids ( Dehmer and Hammer 2004). Based on its distribution, molecular and crossing experiments, it is believed to be the diploid parent of the two hexaploids S. nigrum and S. scabrum ( Edmonds 1979a, Ganapathi and Rao 1987a, 1987b). There are a relatively few differences between the two species in SSR ( Dehmer 2001), AFLP ( Dehmer and Hammer 2004), RAPD ( Poczai et al. 2010), ISSR and SCoT ( Poczai and Hyvönen 2011) and intron-targeting markers ( Poczai et al. 2014) and a number of additive bands could be counted between S. americanum and the two hexaploids indicating their parental relationships. Solanum americanum is also the putative parent of the tetraploid S. villosum ( Poczai and Hyvönen 2011).

The taxonomic status and relationship of S. americanum to S. nodiflorum was studied by Manoko et al. (2007). Solanum nodiflorum has been considered as a distinct taxon by some (e.g. Henderson 1974, Heiser et al. 1979) while a synonym or infraspecific taxon of S. americanum by others (e.g. Edmonds 1971; D’Arcy 1974a, b; Symon 1981). Manoko et al. (2007) used AFLP data to study the relationship between the two taxa, but used different taxon concepts than we adopt here, in part because their examination of type specimens was limited. Based on detailed study of the voucher material used, it is clear that the taxon referred to as S. nodiflorum in Manoko et al. (2007) refers to what is considered S. americanum in this treatment, while material referred to as S. americanum represents S. nigrescens M.Martens & Galeotti, a species endemic to the New World. Such confusion is easy in this complex group when studying only a portion of species and their ranges even though type material was consulted in the original paper by Manoko et al. (2007). The taxon referred to as Solanum sp. from Brazil in Manoko et al. (2007) also refers to S. americanum as treated here, but represents a morphological variation mainly observed within the New World and was hence difficult to interpret with limited sampling in previous studies. The re-examination of the study results by Manoko et al. (2007) in the light of the new identifications, highlights the fact that clear population structure can be observed within S. americanum as circumscribed here, where populations from Brazil show high genetic divergence from the rest of the World, including northern South American material.

The results described above, based on AFLP markers, should be tested with modern population genetic tools such as functional markers ( Poczai et al. 2013) or genotyping-by-sequencing (GBS) and phylogenetic analysis. Species-level phylogenetic studies with multiple accessions of all species would also be useful in confirming the monophyly of the highly variable and widespread S. americanum in the context of other species of the Morelloid clade.

Edmonds (2012) incorrectly designated as the lectotype of S. nigrum var. patulum L. a specimen in the Dillenian herbarium at OXF. This typification is in conflict with the protologue (see McNeill et al. 2012, Art. 9.19) because the specimens themselves are not original material for this name. Linnaeus never saw Dillenius’s herbarium ( Jarvis 2007), but based his name entirely on the plates from Hortus Elthamensis ( Dillenius 1732). We have therefore re-lectotypified this name based on original material and designated the specimen chosen by Edmonds as the epitype.

The identity of the species depicted in plate 355 ( Dillenius 1732) has been the subject of much speculation. Thellung (1927) studied material in Dillenius’ herbarium at OXF in an attempt to come to grips with the identity of S. dillenii (see below) and made careful annotations on specimens associated with plate 355. Material stored under plate 355 is mixed; some specimens are of the North American endemic S. emulans Raf. with 9-11 stone cells, calyx lobes appressed to the berry and matte fruit texture and others are of S. americanum with no or up to 4 stone cells, strongly reflexed calyx lobes in fruit and shiny mature berries. Thellung (1927) associated the name S. dillenii with the Dillenian specimens of the North American native S. emulans , but did not realise that there were two taxa involved in the material stored under plate 355. Polgár (1939) re-described S. dillenii , confining it to his original circumscription ( Polgár 1926) and equating it with S. nodiflorum and coined a new epithet, S. dillenianum Polg. for the North American material in the Dillenian herbarium that had been called S. nigrum var. dillenii by Gray (1878). We have epitypified the name S. nigrum var. patulum to conform with current usage because, in our view, the plate is unambiguously of a plant of S. americanum with small flowers, black fruit and sepals that are strongly reflexed in fruit.

Solanum papilionaceum was almost certainly described from living material only. Dumont de Courset (1802: 135) cited no specimens and gave no other provenance than "Cette morelle, qui m’a été envoye en graines du Jardin. nat". Searches in Paris have revealed no authentic original material, so we have selected a neotype that is a specimen dated after the description that was cultivated in Paris (P00582223). The specimen matches the description, which is of a plant with small flowers in umbelliform inflorescences and fruits like “cassis” (blackcurrants).

The specimens in Zuccagni’s herbarium in Florence were consumed by fire, making the designation of a neotype for S. strictum Zucc. necessary. The specimen we have selected is dated later than the description, but is labelled as " Solanum strictum Zucc." and is from Italy in cultivation (G00144215); it was used by Dunal in his Prodromus treatment as S. strictum ( Dunal 1852).

The identity of Schultes’s (1814) name S. dillenii has a complex history. Schultes (1814) coined a replacement name because the epithet “patulum” had been used at the species rank by Persoon (1805: 223) for the Peruvian taxon now known as S. ruizii S.Knapp (see Knapp 1989, 2013). He did not realise that Roth (1800) had already recombined Linnaeus’ S. nigrum var. patulum (see above) at the specific rank, basing his description entirely on Hortus Elthamensis plate 355 ( Dillenius 1732). In his protologue, Schultes refers to a collection by Kitaibel from Hungary ("das ich vor mir habe" [which I have before me]) and the illustration in Hortus Elthamensis ( Dillenius 1732) and describes a plant with small flowers and fruits borne on erect pedicels. Polgár (1926) examined the specimen in Kitaibel’s herbarium ("A IX Fasc. 102") labelled " Solanum nigrum an Solanum patulum , Esse Solanum patulum affirmat Willdenow. In silvis Matrae " and equated the specimen with the American species he called S. nodiflorum Jacq. and suggested it was not native to Hungary, but rather from a botanic garden. This sheet (Herb. Kit. Fasc. IX, No. 102) in BP is a tangled mixture of two elements (see Poczai et al. 2009). One stem has small flowers in sub-umbellate inflorescences and matches the protologue description (but has no fruit) and the other stem has larger flowers in elongate racemose inflorescences and was identified by Poczai et al (2009) as S. scabrum. It is quite possible that there was considerable mix-up with the labelling of plants in Kitaibel’s herbarium; a specimen at BP (Herb. Kit. Fasc. IX, No. 101), exactly matching the small-flowered stem of Herb. Kitaibel fasc. IX, No. 102, is labelled " Solanum nigrum β Solanum patulum " in Kitaibel’s hand and "ex horto" in another hand. It is possible that the large-flowered plants collected in Mátra (which we identify as S. nigrum ) were mixed with small-flowered plants from cultivation and, in distributing duplicates, confusion ensued. As Schultes (1814) cited a specimen (see McNeill et al. 2012, Art. 9.12), we have lectotypified S. dillenii with the only sheet in the Kitaibel herbarium (BP) that bears the locality cited in Schultes’s (1814) protologue, but limit our typification to the stem with small flowers only. A sheet in B-W [B-W 04364-03] of Kitaibel’s with a label in his hand "161/ Solanum nigrum an Solanum patulum ?/In sylvis Hungaria" is certainly a duplicate; we cannot be sure this is the sheet Schultes had in his possession, since the locality is not exactly the same as that in the protologue and it does not have fruit. The BP sheet (fasc. IX No. 101) is also possibly a duplicate; it does have berries borne on erect pedicels. Gray (1878) used Schultes’s epithet at the infraspecific rank (as S. nigrum L. var. dillenii (Schult.) A.Gray) for plants from north-eastern North America now known as S. emulans Raf.

In describing S. microspermum , Dunal (1816) used an unpublished name by L’Heritier and cited a specimen and his own unpublished illustration, now held in MPU. We have selected the specimen in G-DC that comes from "herb. Thibaud" and is annotated by Dunal as the lectotype. The online catalogue at G indicates the collector of this sheet as “L’Héritier de Brutelle".

Although the protologue of S. erythrocarpon ( Meyer 1818) indicates the fruits are red ("Baccae pendulae, pisi minoris magnitudine, lutescenti-rubrae, nitidae"), the specimen in GOET (GOET003505) that represents original material for this name (here selected as the lectotype) matches S. americanum in all other respects.

D’Arcy (1974a: 735) cited as “type” a specimen in P as "Type: Herb. Rich. (P)" with a footnote stating that the sheet has two labels, one with "Isle de France" in Dunal’s hand and the other indicating it is from Herb. Richard. Since the protologue does not mention Isle de France and Dunal had nothing to do with the description of this name, this unintentional lectotypification is in conflict with the protologue, in which the locality is "insulae Cubae" and Richard is mentioned. We therefore supersede it and designate a specimen in P (P00370899) that matches the protologue in being from Cuba and originally from Herb. Richard as the lectotype for S. indecorum .

Sendtner (1846) described his var. Solanum nigrum aguaraquiya referring to Piso’s (1648: 55) pre-Linnaean name “Aguara-quiya” and citing un-numbered collections of Sellow and one Martius collection with a number and locality we have here selected as the lectotype. The Sellow collections associated with this name (BR [BR0000005538058], K, W [W0004136]) have large anthers and represent S. chenopodioides ; they have neither numbers nor localities. The specimen selected as lectotype here (Martius 1225, M-0171809) contains detail of collection locality cited in the protologue and is hence the best material.

D’Arcy (1974a) lectotypified both S. amarantoides (Gaudichaud 552) and S. nodiflorum var. acuminatum (Vauthier 537) by stating “type” and a single herbarium, “P”. In the case of S. amarantoides , two specimens are found in P; we have selected that which has a label with Dunal’s handwriting in a second step lectotypification (P00319574). For S. nodiflorum var. acuminatum , however, D’Arcy (1974a) cited "P, ex Herb. Drake", indicating a single specimen. Unfortunately, this specimen (P00319615) is not the duplicate of Vauthier 537 with Dunal’s label (that with the annotation from Dunal is P00315614), but must be accepted as the lectotype nevertheless.

In describing S. minutibaccatum , Bitter (1912a) cited a single Buchtien collection (Buchtien 1443), but no herbarium. We have selected the sheet in US (US00027684) as the lectotype because it is the best preserved of the duplicates we have seen.

Solanum calvum was described using " Palmer 60 p. pte." ( Bitter 1913b) with a single herbarium cited ("herb. Upsal."). Edward Palmer began his number series again on every collecting trip ( McVaugh 1956), but the collection number in question here refers to plants collected on Guadalupe Island (Baja California) in 1875. Other duplicates of Palmer 60 (another sheet at UPS, MO [MO-158569]) are part of type material of S. profundeincisum Bitter, a synonym of Solanum douglasii Dunal from Mexico and the south-western United States, while others are of material of S. nitidibaccatum (BM001017193 and MO-158570). We exclude these as types of S. calvum and urge caution when interpreting other duplicates of Palmer 60.

The protologue of S. nigrum var. pauciflorum ( Liou 1935) cited three specimens from Hainan Island; Chen 1, Wang 2 and Lau 209, all perhaps from LU, although no herbarium was cited. We select here the more widely distributed Lau 209 with the BM sheet (BM000942311) as lectotype for this name.

Selected specimens examined.

A total of 1,074 specimens were examined from 73 countries during the study across Africa, Asia, Australia, Eurasia and the Pacific. Specimens from the New World were also studied in order to understand the full range of morphology within the species. All specimens examined from the Old World can be seen in Appendix 2 (csv format) and Appendix 3 (traditional Specimens Examined list in pdf format).

Figures

Figure 7. Solanum americanum Mill A Habit B Detail of abaxial leaf surface C Detail of adaxial leaf surface D Branch with inflorescence E Leaf F Dissected flower G Fruit (A-D, F-G Cremers 8084; E Farrugia 2773). Drawing by R. Wise.

Figure 8. Solanum americanum Mill A Habit B Leaves and young inflorescence C Buds and flowers D Mature, shiny black fruits with reflexed calyx lobes (A, D Knapp et al. 10210; B Knapp et al. 10205; C Knapp et al. 10360). Photos by S. Knapp.

Figure 9. Distribution of Solanum americanum Mill in the Old World.