51. Solanum sarrachoides Sendtn., Fl. Bras. (Martius) 10: 18, tab. 1, figs 1-8. 1846.

Figs 155, 156

Solanum sarachidium Bitter, Repert. Spec. Nov. Regni Veg. 11: 211. 1912. Type. Paraguay. Gran Chaco: Loma Clavel, Nov 1903, T. Rojas 2493 (lectotype, designated by Edmonds 1986, pg. 17: BM [BM000087577]; isolectotype: G [G00306752]).

Solanum sarrachoides Sendtn. var. sarachidium (Bitter) C.V.Morton, Revis. Argentine Sp. Solanum 122. 1976. Type. Based on Solanum sarachidium Bitter.

Type.

Brazil. "Brasilia australis", F. Sellow s.n. (lectotype, designated by Edmonds 1986, pg. 16: P [P00371162]).

Description.

Annual herbs to 0.7 m high, usually smaller (but very rarely to 1 m), spreading and decumbent with age. Stems terete, green, generally erect, branching and later spreading, not markedly hollow; new growth densely viscid-pubescent with simple, uniseriate, spreading trichomes with a glandular apical cell, the trichomes of two lengths, 1-4-celled trichomes to 0.5 mm long and 5-14-celled trichomes to 2 mm long; older stems glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple and sinuate-dentate, the blades 3-7.5 cm long, 3-6 cm wide, broadly ovate, widest in the lower third, thinly membranous, concolorous; adaxial and abaxial surfaces sparsely to densely pubescent with spreading, simple, uniseriate glandular trichomes like those of the stem, evenly distributed on lamina and veins; major veins 3-4 pairs; base truncate to cordate, sometimes asymmetric; margins entire or regularly sinuate-dentate; apex acute; petioles 0.5-3.2 cm long, sparsely pubescent with trichomes like those of the stem and leaves. Inflorescences usually opposite the leaves but occasionally internodal (always very near the node), unbranched, 0.7-1.7 cm long, with 2-5(6-7) flowers clustered at the tip (sub-umbelliform), sparsely pubescent with spreading trichomes like those of the stems; peduncle 0.7-1 cm long; pedicels 5-7 mm long, 0.1-0.2 mm in diameter at the base, 0.3-0.4 mm in diameter at the apex, straight and spreading, articulated at the base; pedicel scars spaced ca. 0(-1) mm apart. Buds globose, the corolla only slightly exserted from the calyx tube before anthesis, almost completely included within the calyx lobes and only the tip of the corolla showing. Flowers 5-merous, cosexual (hermaphroditic). Calyx tube 0.5-1 mm long, the lobes 1.5-2 mm long, 1.3-1.5 mm wide, lanceolate to narrowly ovate with acute apices, sparsely pubescent with 1-4-celled spreading glandular trichomes like those on the pedicels but shorter. Corolla 0.5-0.8 cm in diameter, white with a yellow-green central eye, pentagonal-stellate, lobed 1/3 of the way to halfway to the base, the lobes 3-4.5 mm long, 5-7 mm wide, spreading at anthesis, sparsely papillate-pubescent abaxially with glandular 1-4-celled simple uniseriate trichomes and eglandular papillae, these denser along margins, tips and midvein. Stamens equal; filament tube minute; free portion of the filaments 1-1.5 mm long, adaxially sparsely pubescent with tangled uniseriate 4-6-celled simple trichomes; anthers 1.2-2 mm long, 0.4-0.8 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary globose, glabrous; style 3-3.5 mm long, straight, not usually exserted beyond the anther cone, densely pubescent with 2-3-celled simple uniseriate trichomes in the lower half to 2/3 where included in the anther cone; stigma capitate, minutely papillate, green in live plants. Fruit a globose berry, 0.6-0.9 cm in diameter, green brownish grey at maturity, the pericarp usually matte, opaque, glabrous; fruiting pedicels 5-9 mm long, 0.2-0.3 mm in diameter at the base, ca. 1 mm in diameter at the apex, spaced 0-1 mm apart, reflexed, not persistent; fruiting calyx accrescent, becoming papery in mature fruit, the tube 3-4 mm long, the lobes 5.5-8 mm long and 3.5-4 mm wide, the tips slightly reflexed or spreading. Seeds (23-)59-69(-93) per berry, 1.3-1.7 mm long, 1-1.5 mm wide, flattened and teardrop shaped with a subapical hilum, pale yellow, the surfaces minutely pitted, the testal cells pentagonal in outline. Stone cells 4-6 per berry, (0.5) 0.8-1 mm in diameter. Chromosome number: 2n = 24 (see Särkinen et al. 2018).

Distribution

(Fig. 157). Solanum sarrachoides is native to southern South America, occurring in Brazil (States of Paraná, Rio Grande do Sul, Santa Catarina, São Paulo,), Bolivia (Dept. Santa Cruz), Argentina (Provs. Buenos Aires, Catamarca, Chaco, Entre Ríos, Formosa, San Luis, Santiago del Estero), Paraguay (Depts. Boquerón, Nueva Asunción, Presidente Hayes) and Uruguay (Depts. Florida, Lavalleja, Montevideo, San José). It is sporadically introduced in the temperate zones of both Northern and Southern Hemispheres, where it is much less common than the morphologically similar S. nitidibaccatum (see Särkinen et al. 2018, Knapp et al. 2019 for details of extra-South American distribution of both these species).

Ecology and habitat.

Solanum sarrachoides occurs in a wide variety of dry and semi-humid habitats, often in open or disturbed areas such as the edges of agricultural fields, and sporadically occurs as a weed of cultivation in urban areas, from sea level to 1,000 m elevation.

Common names and uses.

Bolivia. Santa Cruz: huiraquillomi (Guaraní, Michel et al. 2769). No uses recorded.

Preliminary conservation status

(IUCN 2022). Least Concern [LC]. EOO = 2,194,057 km2 [LC]; AOO = 128 km2 [EN]; calculated on South American range only. Solanum sarrachoides is widespread in the Paraná Basin and is a weedy somewhat ephemeral species in a wide variety of habitats; it is introduced elsewhere as an agricultural weed (see Särkinen et al. 2018; Knapp et al. 2019 for details).

Discussion.

Many accounts of morelloid solanums from outside South America have treated as Solanum sarrachoides specimens of the species whose correct name is S. nitidibaccatum (see references in Särkinen et al. 2018; Knapp et al. 2019). Records of S. sarrachoides in the literature should therefore be dealt with care due to common misidentification of voucher material. The two species can be distinguished based using the following suite of characters: S. sarrachoides has generally truncate leaf bases, umbellate to sub-umbellate mature inflorescences opposite the leaves (Fig. 156B) with fewer flowers (2-5), shorter calyx lobes 1-1.4 mm long and a corolla with yellow-green central eye. Solanum nitidibaccatum has cuneate leaf bases, usually internodal mature inflorescences with an elongate flower-bearing axis with more flowers (4-8), longer calyx lobes 1.8-2.5 mm long, and corolla with black-purple edged central eye. The accrescent calyx almost completely encloses the matte-surfaced mature berry in S. sarrachoides, while the shiny, marbled berry of S. nitidibaccatum is always ca. halfway exserted from the calyx lobes. Solanum sarrachoides usually has more stone cells in each berry (4-6) than does S. nitidibaccatum (1-2, or absent). Though morphologically very similar, data from both nuclear and plastid DNA sequences suggests the two species are not closely related (Gagnon et al. 2022).

Typification details of the synonyms of S. sarrachoides can be found in Barboza et al. (2013) and Särkinen et al. (2018).