Solanum torvum [Sw. ]

Solanum torvum

Citation author:

Sw.

Citation:

Prodr. [O. P. Swartz] 47. 1788.

Type:

“Indiae occidentalis” [“Provenit in sepibus Jamaicae, Hispaniolae, Insulis Bermudensibus” Swartz 1797: 456], O. Swartz s. n. (lectotype, designated by Vorontsova & Knapp Syst Bot Monog in press: S! [S-R-5814]).

Last edited by:

Sandra Knapp (May 2014)

Written by:

Maria S. Vorontsova & Sandra Knapp

Habit:

Shrubs to 3 m, many-branched from the base, armed or unarmed. Young stems terete, pubescent with a mixture of short- and long-stalked porrect trichomes to 0.5 mm, the stalks multiseriate, the rays 6-8, 0.5-1 mm, the midpoint absent or much reduced, occasionally a few multangulate trichomes scattered along the stem, often sparsely prickly with broad-based, curved prickles to 10 mm long, glabrescent; new growth densely stellate-pubescent, the young leaves discolorous; bark of older stems dark brownish gray.

Sympodial structure:

Sympodial units difoliate, usually geminate.

Leaves:

Leaves simple, the blades (5.5-)9-17 cm long, (4-)5-12 cm wide, ca. 1.5 times as long as wide, if geminate the minor leaf ca. half the size of the major but not differing in shape, elliptic to ovate, somewhat discolorous when dry, membranous; adaxial surfaces evenly and sparsely to densely pubescent with sessile porrect stellate trichomes, the rays 4-6, ca. 0.2 mm long, the midpoints to 0.5 mm long, always longer than the rays, the lamina clearly visible; abaxial surfaces densely pubescent with short- to long-stalked porrect stellate trichomes to 0.5 mm long, the stalks multiseriate, the rays 6-8, to 0.5 mm long, the midpoints absent or much reduced, the lamina not visible; primary veins 3-4 pairs, densely pubescent; base truncate, oblique; margins entire or shallowly lobed, the lobes broadly triangular, never more than 1/3 of the way to the midrib; apex acute to acuminate; petioles 1.5-4 cm long, densely stellate-pubescent like the stems, with a few scattered prickles to 10 mm long, curved or almost straight.

Inflorescences:

Inflorescences lateral or occasionally leaf-opposed, 2-6 cm long, 1-4 times branched, with more than 50 flowers, densely pubescent with short-stalked porrect stellate trichomes like those of the stems, distally with simple glandular trichomes like those of the pedicels; peduncle 0.5-2 cm long; pedicels 1-1.2 cm long, ca. 0.5 m in diameter, slender, sparsely to densely pubescent with sessile stellate trichomes with glandular midpoints and simple unicellular gland-tipped trichomes, articulated at the base; pedicel scars irregularly spaced 1-3 mm apart.

Flowers:

Flowers 5-merous, all perfect. Calyx 4-6 mm long, sparsely to densely stellate-pubescent and glandular, the stellate trichomes denser than on the pedicels, unarmed or with a few short prickles, the lobes 3-4 mm long, the caudate tip ca. 1 mm long. Corolla 1.5-2 cm in diameter, white, stellate, lobed ½ to 2/3 of the way to the base, the lobes 7-9 mm long, 4-5 mm wide, spreading or slightly reflexed at anthesis, densely stellate-pubescent along and around the midvein abaxially, glabrous adaxially. Stamens equal, connivent, the filament tube < 0.5 mm long, the free portion of the filaments ca. 1 mm long, glabrous; anthers 6-8 mm long, ca. 1 mm wide, connivent, tapering, poricidal at the tips, the pores directed upwards. Ovary conical, minutely glandular; style 10-12 mm, glabrous; stigma capitate, green in live plants, minutely papillate.

Fruits:

Fruit a globose berry, 5-40+ per infructescence, 1-1.3 cm in diameter, pale grayish green when ripe, the pericarp thin and matte to slightly shiny, glabrous; fruiting pedicels 1.2-.15 cm long, ca. 2 mm in diameter, thicker towards the apex, woody and spreading to somewhat pendant; fruiting calyx persistent, the lobes to 5 mm long.

Seeds:

Seeds > 100 per berry, 2.5-3 mm long, 2-2.5 mm wide, flattened reniform, pale yellowish tan, the surfaces minutely pitted to smooth, the testal cells deeply sinuate in outline.

Chromosome number:

n=12

Distribution:

Probably native to the Caribbean and Central America, Solanum torvum is naturalized in many tropical and subtropical regions worldwide, usually at low elevations.

Phenology:

Flowering and fruiting throughout the year.

Phylogeny:

Solanum torvum is a member of the Torvum Clade of subgenus Leptostemonum (Stern et al. 2011).

Commentary:

Solanum torvum is one of the most widespread species of spiny solanums; it occurs throughout the tropics and subtropics worldwide, and is very common where it occurs, often being the dominant Solanum species in the environment. It is a member of the Torva clade (Stern et al. 2011) and native to the New World. In the Caribbean and eastern Central America it is very common in disturbed areas a low elevations, it also occurs in northeaster South America to coastal Brazil, where it is common in low restingas near the coast.

Solanum torvum could be confused with many native species of Solanum in the Old World, particularly those in the non-andromonecious Anguivi grade, but can be distinguished by the combination of fruit green at maturity, inflorescences with small simple, gland-tipped trichomes, perfect flowers, and broadly elliptic to ovate leaves. Solanum anguivi in particular is also widespread, but is distinguished from S. torvum by its red fruit and smaller flowers (8-15 mm in diameter versus 15-20 mm).

Solanum torvum is a name that has been in long use. Knapp (2011a) considered it to be not validly published and proposed it for conservation with a conserved type so not to upset this usage. The Nomenclature Committee for Vascular Plants (Applequist 2013) considered the proposal to be unnecessary and that the name was validly published, thus obviating the need for a conserved type. We have selected as the lectotype (S-R-5814) is one of three sheets in the Swartz herbarium in S, and the only one that bears a label in Swartz’s hand.

Solanum daturifolium was described by Dunal (1852) using three collections; Sieber 67 from Martinique, Lhotsky s. n. (G-DC) from Brazil and another specimen cultivated in Montpellier in 1824 (no sheets found). Nee (Nee et al. 2006) assumed that Schulz (1909) typified this name by citing the Sieber specimens, but Schulz’s statement “(quoad specim. Sieb.)” in the citation of the basionym does not constitute typification, even by the standards of the day. The Lhotsky specimen has been identified as belonging to S. scuticum M. Nee (Nee et al. 2006), so in order to fix the name S. daturifolium as a synonym of S. torvum (and not replace the more recently described S. scuticum) it is necessary to lectotypify it with Sieber 67. Dunal cited a specimen in “Herb. Boiss.” that is now in the general herbarium at G; this has been selected as the lectotype from amongst the duplicates of this collection we have seen.

Solanum macaonense was recognized as distinct from S. torvum in the Flora of China (Zhang et al. 1994) based on material collected in Guangdong and Hainan provinces. The type specimen of S. macaonense at P is clearly conspecific with S. torvum; it has the distinctive glandular inflorescences of that species. Plants identified as S. macaonense in the Flora of China are referable to S. inaequilaterale Merr., a species originally described from the Philippines.

Solanum mannii and S. largiflorum, described from West Africa and Australia respectively, are both clearly conspecific with S. torvum. We have chosen Mann 55 at K as the lectotype of S. mannii, as a copy of the protologue is attached to the sheet which is annotated in Wright’s hand. Two specimens of White & Francis s. n. (MEL, NSW) were cited in the protologue of S. largiflorum; we have selected the sheet at MEL [MEL-12431, without Francis as the co-collector] as the lectotype.

References:

Applequist, W. L. 2013. Report of the Nomenclature Committee for Vascular Plants: 65. Taxon 62: 1315-1326.

Knapp, S. 2011a. (2030) Proposal to conserve the name Solanum torvum (Solanaceae) with a conserved type. Taxon 60: 1523-1524.

Levin, R. A., N. R. Myers, and L. Bohs. 2006. Phylogenetic relationships among the “spiny solanums” (Solanum subgenus Leptostemonum, Solanaceae). Amer. J. Bot. 93: 157-169.

Nee, M., L. Bohs & S. Knapp. 2006. New species of Solanum and Capsicum (Solanaceae) from Bolivia, with clarification of nomenclature in some Bolivian Solanaceae. Brittonia 58: 322-356.

Schulz, O. 1909. Symbolae Antillanae 6: 236.

Stern, S. R., M. de F. Agra, and L. Bohs. 2011. Molecular delimitation of clades within New World species of the ”spiny solanums” (Solanum subgenus Leptostemonum). Taxon 60: 1429-1441.

Zhang, Z.-Y., A.-M. Lu, and W. G. D’Arcy. 1994. Solanaceae, In: eds., Z.-Y. Wu and P. R. Raven. Flora of China 17: 300-332.

Common names and uses:

Local Names. Devil’s fig, pea eggplant (English); Madagascar: angivybe.

Uses. Fruit used in cooking, in Asia and in Asian communities.

Conservation status:

Least Concern (LC); Solanum torvum is a widespread, circumtropical weed.

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Solanum torvum Sw.

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