Solanum chenopodioides Lam., Tabl. Encycl. 2: 18. 1794.

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

11. Solanum chenopodioides Lam., Tabl. Encycl. 2: 18. 1794.

Figs 35 , 36

Solanum sublobatum Willd. ex Roem. & Schult., Syst. Veg., ed. 15 bis [Roemer & Schultes] 4: 664. 1819. Type. Argentina. Buenos Aires, Anon. s.n. [probably P. Commerson] (Herb. Willdenow 4336) (lectotype, designated by Edmonds 1972, pg. 105 [as type ex photo]: B [B-W04336-01-0]).

Solanum besseri Weinm., Syst. Veg., ed. 15 bis [Roemer & Schultes] 4: 593. 1819. Type. "In America" [cultivated in Europe?], Anon. s.n. (no specimens cited; no original material located; neotype, designated by Särkinen et al. 2018, pg. 65: G-DC [G00144198]).

Solanum subspatulatum Sendtn., Fl. Bras. (Martius) 10: 45, tab. 4, figs 16-18. 1846. Type. Brazil. Sin. loc., F. Sellow s.n. (holotype: B, destroyed [F neg. 3183]; lectotype, designated by D’Arcy 1974a, pg. 735 [as type]: P [P00384051]; isolectotype: F [v0361921F, acc. # 621700, fragment]).

Witheringia chenopodioides (Lam.) J. Rémy, Fl. Chil. [Gay] 5: 69. 1849. Type. Based on Solanum chenopodioides Lam.

Solanum chenopodiifolium Dunal, Prodr. [A. P. de Candolle] 13(1): 44. 1852. Type. Argentina/Uruguay. "Buenos Aires et Montevideo", P. Commerson s.n. (lectotype, designated by Edmonds 1972, pg. 108 [as holotype], second step designated by Särkinen et al. 2018, pg. 65: P [P00384081]).

Solanum gracile Dunal, Prodr. [A.P. de Candolle] 13(1): 54. 1852, nom. illeg., not Solanum gracile Sendtn. (1846). Type. Brazil. Rio de Janeiro: "Rio de Janeiro", 1831-1833, C. Gaudichaud 520 (lectotype, designated by Henderson 1974, pg. 46: G-DC [G00144391]; isolectotypes: G [G00343457], P [P00384052, P00384053]).

Solanum gracile Dunal var. microphyllum Dunal, Prodr. [A. P. de Candolle] 13(1): 54. 1852. Type. Argentina/Uruguay. "Circa Buenos Ayres et Montevideo", P. Commerson s.n. (lectotype, designated by Morton 1976, pg. 151: P [P00384061, Morton neg. 8207]; possible isolectotype: F [v0073283F, acc. # 976485, fragment only]).

Solanum isabellei Dunal, Prodr. [A. P. de Candolle] 13(1): 153. 1852. Type. Uruguay. Montevideo, Lat. aust. 34°45'08", 1838, A. Isabelle s.n. (lectotype, designated by Särkinen et al. 2018, pg. 65: G-DC (G00145645); isolectotypes: F [v0073298F, acc. # 680251; v0073299F, acc. # 680253], K [K000585686], P [P00384071], W [acc. # 1889-115034]).

Solanum nodiflorum Jacq. var. microphyllum Hassl., Repert. Spec. Nov. Regni Veg. 9: 118. 1911. Type. Paraguay. Estrella: Mar, É. Hassler 10271 (holotype: G [n.v.], Morton photo 8612).

Solanum vile Bitter, Repert. Spec. Nov. Regni Veg. 11: 221. 1912. Type. Brazil. Rio de Janeiro: Restinga do Harpoador, E. Ule 4310 (lectotype, designated by Särkinen et al. 2018, pg. 66: CORD [CORD00004277]; isolectotype: HBG [HBG511507]).

Solanum gracilius Herter, Rev. Sudamer. Bot. 7: 266. 1943. Type: Based on (replacement name for) S. gracile Dunal.

Solanum ottonis Hyl., Uppsala Univ. Årsskr. 7: 279. 1945. Type. Based on (replacement name for) Solanum gracile Dunal.

Type.

Mauritius. "Ex ins. Mauritiana", Herb. Lamarck s.n. (lectotype, designated by Barboza et al. 2013, pg. 242: P [P00357629]).

Description.

Annual herbs to short-lived perennial shrubs up to 1 m high, subwoody and branching at base. Stems terete, green-grey to straw colour, sprawling, somewhat weak and decumbent, not markedly hollow; new growth usually densely pubescent with simple, uniseriate appressed 1-6-celled eglandular trichomes, these 0.1-0.6 mm long; older stems more sparsely pubescent, glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple, the blades 1.5-5.5(-7) cm long, 0.5-3(-3.5) cm wide, lanceolate to narrowly ovate, rarely ovate, widest at the middle or slightly below, membranous, discolorous; adaxial surface green, sparsely pubescent with appressed 1-4-celled translucent, simple, uniseriate trichomes like those on stem, these denser along the veins; abaxial surface pale grey, more densely pubescent with trichomes like those of the upper surface evenly distributed across lamina and veins; major veins 3-6 pairs, not clearly evident abaxially; base attenuate, decurrent on the petiole; margins entire or sinuate; apex acute to obtuse; petioles (0.5-)1-1.5(-3.5) cm long, sparsely pubescent with simple uniseriate trichomes like those of the stems and leaves. Inflorescences generally internodal but appearing to arise opposite the leaves on young shoots, unbranched or rarely forked, 1-2.5(-4) cm long, with 3-7(-10) flowers clustered near the tips (sub-umbelliform), sparsely pubescent with appressed 1-2-celled simple uniseriate trichomes; peduncle 1-2.3(-4) cm long, strongly deflexed downwards in fruit; pedicels 5-10 mm long, ca. 0.5 mm in diameter at the base and 1 mm in diameter at the apex, straight and spreading, articulated at the base; pedicel scars spaced ca. 0-1 mm apart. Buds elongate-oblong, the corolla only slightly exserted from the calyx tube before anthesis. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube 2-3 mm long, conical, the lobes 0.6-1.2 mm long, less than 1 mm wide, broadly deltate to triangular with acute to obtuse apices, sparsely pubescent with 1-4-celled appressed hairs like those on stem but shorter. Corolla 0.6-1.2 cm in diameter, white with a black and yellow-green central portion near the base, the black colour usually distal to the yellow green, deeply stellate, lobed 4/5 of the way to the base, the lobes 3.5-4 mm long, 1.5-1.9 mm wide, strongly reflexed at anthesis, later spreading, densely puberulent-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 0.6-1 mm long, adaxially pubescent with simple tangled uniseriate 4-6-celled simple trichomes; anthers (2-)2.3-2.8 mm long, 0.5-0.8 mm wide, narrowly ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying, the connective becoming darker brown with age in dry plants. Ovary globose, glabrous; style 3.7-4.5 mm long, straight, exserted beyond the anther cone, densely pubescent with 2-3-celled simple uniseriate trichomes in the lower half where it is included in the anther cone, exserted up to 1.5 mm beyond the anther cone; stigma capitate, minutely papillate, green in live plants. Fruit a globose berry, 0.4-0.9 cm in diameter, dull purplish black at maturity, the pericarp thin, matte and somewhat glaucous, opaque, glabrous; fruiting pedicels 0.6-1.3 cm long, (0.4)0.8-1.4 mm in diameter at the base, 1-2 mm in diameter at the apex, deflexed and slightly curving, not persistent, but the downwards pointing peduncle often persistent on older stems; fruiting calyx not accrescent, the tube less than 1 mm long, the lobes 1-1.5 mm long, appressed against the berry. Seeds (13-)20-35(-50) per berry, 1.2-1.4 mm long, 1-1.2 mm wide, flattened and teardrop shaped with a subapical hilum, pale yellow, the surfaces minutely pitted, the testal cells pentagonal in outline. Stone cells absent. Chromosome number: 2n = 24 (see Särkinen et al. 2018).

Distribution

(Fig. 37 ). Solanum chenopodioides is native to southern South America, and has been introduced globally, largely with the wool trade. In South America it is known from the littoral of Argentina (Provs. Buenos Aires, Chaco, Córdoba, Corrientes, Entre Rios, Jujuy, La Pampa, La Rioja, Mendoza, Río Negro, Salta, San Luis, Santa Fé, Tucumán), southern Brazil (Provs. Mato Grosso do Sul, Minas Gerais, Rio de Janeiro, Paraná, Rio Grande do Sul, São Paulo and Santa Catarina), Paraguay (Depts. Amambay, Canindeyú, Itapúa, Presidente Hayes) and Uruguay (Colonia, Florida, Lavalleja, Maldonado, Montevideo, Rivera, Rocha, Salto, San José, Tacuarembó) with sporadic occurrences elsewhere, where it may be introduced.

Ecology and habitat.

Solanum chenopodioides is a weedy species, growing in disturbed areas in many different vegetation types, close to urban areas and human-altered habitats; from 0 and 2,400 m elevation.

Common names and uses.

Argentina. Buenos Aires: kushú-kushú (as S. sublobatum , Martínez Crovetto 1968), yerba mora (Robles et al. 1869); Córdoba: yerba mora ( Müller et al. 308); Salta: iój s(l) I s(l) I (Vilela, as S. gracile , Martínez Crovetto 1965). Uruguay. Montevideo: yerba mora (Barattini s.n.). Solanum chenopodioides is considered to be toxic for cattle due to the high solanidine content of unripe fruits ( Marzocca 1994), but as fruits ripen the alkaloid content decreases and fruits are apparently eaten without effect ( Gallo 1987). In Argentina, fruits of S. chenopodioides are eaten by children of the Araucarian peoples ( Martínez Crovetto 1968) and the Vilela people use them as a purple dye ( Martínez Crovetto 1965).

Preliminary conservation status

( IUCN 2022). Least Concern [LC]. Worldwide distribution: EOO = 95,008,211 km2 [LC]; AOO = 1,560 km2 [LC]. Solanum chenopodioides is a widespread weed of disturbed areas (see Barboza et al. 2013; Särkinen et al. 2018; Knapp et al. 2019) and is widely introduced outside of and very common within its native range.

Discussion.

Solanum chenopodioides is a weedy, ruderal species occurring in open disturbed areas throughout its range. It is somewhat similar morphologically to S. pilcomayense , with which it is sympatric in Argentina, but differs in its elliptic leaves with acute to attenuate bases (versus triangular leaves with truncate to hastate bases), smaller anthers (2-2.8 mm long versus 3-4 mm long), and deltate or triangular versus spathulate calyx lobes. The fruiting peduncle of S. chenopodioides bends downwards at the base so it is held at an angle of ca. 45-degree with respect to the stem (see Figs 35G , 36D ), but this character is not always obvious in herbarium specimens. Anthers in S. chenopodioides are always much longer (2-2.8 mm) than in S. americanum (0.8-1.5 mm), and the berries are matte (versus shiny) in texture and always lack stone cells (versus often with 2-4 stone cells per berry in S. americanum ).

Typification details for the synonyms of S. chenopodioides and a more comprehensive discussion of its worldwide distribution as a weed of wool waste used in agriculture can be found in Särkinen et al. (2018) and Knapp et al. (2019).

Figures

Figure 35. Solanum chenopodioides A habit B detail of adaxial leaf surface C detail of abaxial leaf surface D opening bud E dissected flower F fruiting branch G detail of infructescence H maturing fruit I fully mature fruit (A-E Fox s. n. F-I Hieronymus s. n.). Illustration by R. Wise. Previously published in Barboza et al. (2013: 242), Saerkinen et al. (2018: 67) and Knapp et al. (2019: 46).

Figure 36. Solanum chenopodioides A habit B buds C flowers at full anthesis D fully mature dull black fruits with appressed calyx lobes (A-D Nijmegen acc. # A 14750051). Photos by S. Knapp and G. van der Weerden. Previously published in Saerkinen et al. (2018: 68) and Knapp et al. (2019: 47).

Figure 37. Distribution map of Solanum chenopodioides in South America. For distribution elsewhere see Saerkinen et al. (2018: 70) and Knapp et al. (2019: 50).