Solanum triflorum Nutt., Gen. N. Amer. Pl. 1: 128. 1818

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 : 97-100

17. Solanum triflorum Nutt., Gen. N. Amer. Pl. 1: 128. 1818 Figure 51 , 52

Solanum triflorum Nutt. var. majus Hook., Fl. Bor.-Amer. 2: 90. 1837, as “major”. Type. Canada. Saskatchewan: "Carleton House Fort, Saskatchewan River", J. Richardson s.n. (lectotype, designated by Särkinen et al. 2018, pg. 167: BM [BM000934745]; isolectotype: K [K001159656, large plants]).

Solanum triflorum Nutt. var. minus Hook., Fl. Bor.-Amer. 2: 90. 1837, as “minor”. Type. Canada. Saskatchewan: "In the Garden (a weed) of Carleton House Fort, entrance of Badger’s Hole, and Saskatchewan River to Edmonton House [protologue]", T. Drummond s.n. (lectotype, designated by Särkinen et al. 2018, pg. 167: E [E00526685]; isolectotypes: BM [BM000934744], K [K001159656]).

Solanum mendocinum Phil., Anales Univ. Chile 21(2): 403. 1862. Type. Argentina. Mendoza: Mendoza, 1860-1861, W. Díaz s.n. (lectotype, designated by Barboza et al. 2013, pg. 260: SGO [SGO000004580]).

Solanum calophyllum Phil., Anales Univ. Chile 21(2): 403. 1862. Type. Argentina. Mendoza: Mendoza, 1860-1861, R. Philippi s.n. (lectotype, designated by Särkinen et al. 2018, pg. 167 [cited as holotype in Barboza et al. 2013]: SGO [SGO000004552]; isolectotype: G [G00343450]).

Solanum pyrethrifolium Griseb., Abh. Königl. Ges. Wiss. Göttingen 24: 250. 1879. Type. Argentina. Tucumán: Lules, Dec 1873, P. G. Lorentz & G. Hieronymus 1132 (lectotype, designated by Morton 1976, pg. 102: CORD [CORD00006111]; isolectotype: GOET [GOET003594]).

Solanum gaudichaudii Dunal var. pyrethrifolium (Griseb.) Kuntze, Revis. Gen. Pl. 3(3): 226. 1898. Type. Based on Solanum pyrethrifolium Griseb.

Solanum triflorum Nutt. var. calophyllum (Phil.) Bitter, Abh. Naturwiss. Vereine Bremen 23: 144. 1914. Type. Based on Solanum calophyllum Phil.

Solanum triflorum Nutt. var. pyrethrifolium (Griseb.) Bitter ex Probst, Mitteil. Naturfor. Gesellsch. Solothurn 9: 41. 1932. Type. Based on Solanum pyrethrifolium Griseb.

Type.8

United States of America. North Dakota: nr. Fort Mandan, Anon. [Lewis & Clark] s.n. (lectotype, designated by Barboza et al. 2013, pg. 260: PH [PH00030496]).

Description.

Annual herbs to 40 cm tall, much branched at the base, to 70 cm in diameter. Stems terete, green, decumbent and prostrate, forming adventitious roots at the nodes, not markedly hollow; new growth glabrous to sparsely pubescent with eglandular simple, uniseriate (3-)4-10-celled spreading trichomes 0.5-2.0 mm long, occasionally with a few glandular trichomes with a 1-many-celled apical gland; older stems glabrescent. Sympodial units difoliate or trifoliate, the leaves not geminate. Leaves simple and shallowly lobed to deeply pinnatifid, (0.5-)2.0-4.0(-5.0) cm long, 0.2-2.9 cm wide, narrowly elliptic to oblong or ovate-elliptic, fleshy in texture, green to dark green; adaxial surface glabrous to sparsely pubescent with simple, uniseriate trichomes like those on stem, scattered along lamina and more densely along the veins; abaxial surface more densely pubescent on veins and lamina; major veins 3-6 pairs, not clearly evident abaxially; base cuneate, decurrent on the petiole; sinuate-lobate to deeply pinnatifid to near-pinnate, with 3-6 linear to triangular pairs of lobes; apex acute; petioles (0.5-)1.0-2.0(-2.4) cm long, pubescent with simple uniseriate trichomes like those of the stems. Inflorescences 1.0-2.0 cm long, internodal, unbranched, with 1 –5(– 6) flowers clustered near the tips (sub-umbelliform), glabrous to sparsely pubescent with spreading trichomes like those of the stems; peduncle 0.8-3.5 cm long, often with apical leafy “bracteoles” (small, leaf-like structures amongst the pedicels); pedicels 3-12 mm long, 0.4-0.5 mm in diameter at the base and 0.4-0.5 mm in diameter at the apex, straight and spreading, articulated at the base; pedicel scars spaced 0(-0.5) mm apart. Buds narrowly ellipsoid or occasionally narrowly ovoid, the corolla exserted 1/5-2/5 from the calyx tube before anthesis. Flowers 5-merous, all perfect. Calyx tube 1.0-1.5 mm long, conical, the lobes 2.5 –3.5(– 7.0) mm long, 0.8 –1.0(– 4.0) mm wide, triangular-oblong with acute apices, densely pubescent with simple, uniseriate eglandular trichomes like those of the stem. Corolla 10-14 mm in diameter, white to lilac with a yellow-green central eye with black-purple coloration at the base, deeply stellate, lobed 1/2-3/4 of the way to the base, the lobes 4.0-5.0 mm long, 1.8-2.2 mm wide, reflexed at anthesis, densely pubescent abaxially with short simple uniseriate eglandular trichomes like those on stems and leaves. Stamens equal; filament tube minute; free portion of the filaments 0.6-1.0 mm long, adaxially sparsely pubescent with tangled simple, uniseriate trichomes; anthers 2.8 –3.1(– 4) mm long, 0.4-0.5 mm wide, narrowly ellipsoid, pale yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary globose, glabrous; style 2.5-3.5 mm long, densely pubescent with 2-3-celled simple uniseriate trichomes to 1/2 from the base, not exserted beyond the anther cone; stigma capitate, minutely papillate, green in live plants. Fruit a globose berry, 8-10(-20) mm in diameter, dark green at maturity, opaque, the surface of the pericarp usually shiny; fruiting pedicels 12-17 mm long, 0.5-1.0 mm in diameter at the base, 1.0-1.5 mm in diameter at the apex, spaced 0 –0.5(– 1.0) mm apart, reflexed and becoming woody, dropping with mature fruits, not persistent; fruiting calyx elongating in fruit, but not becoming papery nor covering the entire fruit, the tube 2.5-3.0 mm long, the lobes (4.0-)4.5 –5.5(– 8.0) mm long and 2.2-3.5 mm wide, strongly reflexed to spreading. Seeds 40-60 per berry, 2.0-2.5 mm long, 1.7-2.0 mm wide, subglobose, yellow, the surfaces minutely pitted, the testal cells pentagonal in outline. Stone cells 13-30, 1.0-1.5 mm in diameter. Chromosome number: 2 n =2 × =24 (South American populations only, see Särkinen et al. 2018).

Distribution.

(Figure 53 ) Solanum triflorum is native to the Americas with a disjunct (amphitropical) distribution between temperate South and North America. In North America it occurs in the United States of America from New Mexico and California north to Canada. The species has been introduced outside its native range in temperate areas of Europe, South Africa and Australia (see Särkinen et al. 2018).

Ecology.

In temperate and boreal regions S. triflorum shows broad ecological lability, growing along road sides, sandy soils, in cultivation, and in salt plains between (0-)700 and 2,900 m elevation.

Common names.

Canada. Wild tomato ( Moss 1983). United States of America. Cut-leaf nightshade (many sources; USDA Plants 2017), Husk tomato (Coombs & Bundy 2456), Three-flowered nightshade ( Peck 1941).

Uses.

Berries eaten in times of food shortages and famine (Acoma, Keres, Laguna peoples); fruit boiled and ground for use in a condiment (Zuni people); decoction of the berries taken for diarrhoea (Blackfoot people), stomach aches (Lakota people), used as lotion for sores on horses (Navajo people); planted with watermelons to make them more prolific and ripen earlier (Keres and Navajo peoples)( Moerman 1998 and references therein).

Preliminary conservation status ( IUCN 2017).

Least Concern (LC); Solanum triflorum is weedy and common where it occurs (see Särkinen et al. 2018). For EOO see Table 6 .

Discussion.

Solanum triflorum is a distinctive species with a prostrate habit, fleshy, usually pinnatifid, leaves, and deeply stellate flowers with long, thin anthers. The inflorescences usually have a small bracetole at the apex, and berry size varies from small (ca. 10 mm) to very large (ca. 20 mm), but usually a given plant has either small or large berries. Numerous stone cells are found in the berries, sometimes almost outnumbering seeds, and large berries can have as many as 30 stone cells. Pubescence of S. triflorum is quite variable (e.g., Subils 1983), and some plants have a few glandular trichomes, but for the most part plants from North America are either glabrous or very sparsely pubescent with spreading and often somewhat tangled simple trichomes.

Solanum triflorum has a classic American Amphitropical Distribution ( Gray and Hooker 1880; Raven 1963; AAD sensu Simpson et al. 2017), with populations oc curing in North and South America, but not between (see also S. nitidibaccatum ). Because of its weedy nature, it is often assumed to be introduced to North America (e.g., https://plants.usda.gov/core/profile?symbol=SOTR), but the amphitropical distribution pattern is found in other Solanaceae native to both regions such as Lycium L. ( Levin et al. 2007), and groups of solanums such as the Carolinense (subsection Lathyrocarpum G.Don, Wahlert et al. 2015, as “section”) and Elaeagnifolium ( Knapp et al. 2017) clades. Solanum elaeagnifolium Cav. (Elaeagnifolium clade, Knapp et al. 2017) has an almost identical amphitropical distribution (sensu Simpson et al. 2017) AAD, and is similarly weedy; it has also been assumed to be introduced. Distribution of these disjunct groups is more likely to be the result of long distance dispersal than of vicariance ( Guilliams et al 2017), with dispersal after being eaten and passed through an animal’s gut (endozoochory) being less common than disperal via attachment to an animal’s fur or feathers (epizoochory) ( Schenk and Saunders 2017); soft juicy berries make endozoochory more likely as a distribution mechanism, although there is no information on frugivores or fruit dispersal for S. triflorum . The distribution of S. triflorum in temperate areas, but also at higher elevations in deserts and into the more boreal regions of North America places it in the temperate AAD category of Simpson et al. (2017); annuals like S. triflorum predominate in this category. Amongst temperate AAD species the most common direction for distribution is from North to South America, but we suspect that like Verbenaceae ( Frost et al. 2017) and Lycium ( Levin et al. 2007), most Solanum disjunctions will have a South America to North America directionality. To date, only North American populations of S. triflorum have been included in molecular phylogenetic studies ( Särkinen et al. 2015b).

Typification details for the synonyms of S. triflorum can be found in Särkinen et al. (2018).

Specimens examined.

See Suppl. materials 1 and 3.

Figures

Figure 51. Solanum triflorum Nutt. A Flowering habit B fruiting habit C flowering branch D detail of adaxial leaf surface E detail of adaxial leaf surface F bud G dissected flower H fruit (A, C, F, G Donat 55; B, D, E, H Baker 577). Drawing by R. Wise (previously published in " PhytoKeys 106 ").

Figure 52. Solanum triflorum Nutt. A Habit B flowering habit C flower and flower bud D flower. (A, D Barboza et al. 2345 B, C Sersic 5040). Photos by G. Barboza and A. Sersic (previously published in " PhytoKeys 106 ").

Figure 53. Distribution of Solanum triflorum Nutt.