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

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

17. Solanum triflorum Nutt., Gen. N. Amer. Pl. 1: 128. 1818 Figures 52 , 53

Solanum triflorum Nutt. var. majus Hook., Fl. Bor.-Amer. 2: 90. 1837, as " major ".

Solanum triflorum Type. Canada. Saskatchewan: "Carleton House Fort, Saskatchewan River", J. Richardson s.n. (lectotype, designated here: BM [BM000934745]; isolectotype: K [K001159656, large plants]).

Solanum triflorum Nutt. var. minus Hook., Fl. Bor.-Amer. 2: 90. 1837, as " minor ".

Solanum triflorum 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 here: E [E00526685]; isolectotypes: BM [BM000934744], K [K001159656]).

Solanum mendocinum Phil., Anales Univ. Chile 21(2): 403. 1862.

Solanum triflorum 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.

Solanum triflorum Type. Argentina. Mendoza: Mendoza, 1860-1861, R. Philippi s.n. (lectotype, designated here [cited as holotype in Barboza et al. 2013]: SGO [SGO000004552]; isolectotype: G [G00343450]).

Solanum pyrethrifolium Griseb., Abh. Königl. Ges. Wiss. Göttingen 24: 250. 1879.

Solanum triflorum 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.

Solanum triflorum Type. Based on Solanum pyrethrifolium Griseb.

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

Solanum triflorum Type. Based on Solanum calophyllum Phil.

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

Solanum triflorum Type. Based on Solanum pyrethrifolium Griseb.

Solanum ponticum Prodan, Bul. Fac. Agron. Cluj 7: 49. 1938.

Solanum triflorum Type. Romania. Satul noi, in arenosis, I.E. Nyárádu s.n. (no original material located; BUCA?, CLA?).

Solanum triflorum Nutt. var. ponticum (Prodan) Borza, Bul. Grad. Bot. Univ. Cluj 22: 20. 1942.

Solanum triflorum Type. Based on Solanum ponticum Prodan

Solanum triflorum Nutt. var. dentatum Ooststr., Gorteria 3: 90. 1966.

Solanum triflorum Type. Netherlands. Gelderland: Nijmegen, bij molen aan de Graafsweg, Jul 1938, B. Reichgelt & T.J. Reichgelt s.n. [Herb. Kern & Reichgelt 4610] (holotype: L [L3384989 [old barcode L0860668], acc. # 951.219 101]).

Solanum triflorum Nutt. forma malvinum De Langhe & D’hose, Belg. J. Bot. 119(2): 160. 1987 [ “1986”].

Solanum triflorum Type. Belgium. Antwerpen, 14 Oct 1984, J.-E. De Langhe & R. D’hose s.n. [219/84] (holotype: "in herbario De Langhe sub numero 219/84", not seen, BR?).

Type.

United States of America. North Dakota : Nr Fort Mandan , Anon. [Lewis & Clark] s.n. (lectotype, designated by Barboza et al. 2013, pg. 260: PH [ PH 00030496]) .

Description.

Annual, decumbent and prostrate herbs to 40 cm tall, much branched at the base, to 70 cm in diameter. Stems decumbent to ascending, terete, green, forming adventitious roots at the nodes, not markedly hollow; new growth glabrous to sparsely pubescent with simple, spreading, uniseriate, translucent, eglandular trichomes, these (3-)4-10-celled, 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- to ovate-elliptic, fleshy in texture, concolorous, without smell; 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, simple, umbelliform to sub-umbelliform, with 1-5(-6) flowers clustered near the tip, glabrous to sparsely pubescent with spreading trichomes like those of the stems; peduncle 0.8-3.5 cm long, straight, often with apical leafy “bracteoles”; pedicels 3-12 mm long, 0.4-0.5 mm in diameter at the base and 0.4-0.5 mm at 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) mm long, 0.8-1.0(-4) 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 colouration at the base, stellate, lobed 1/2-1/3 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 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 in the lower half, not exserted beyond the anther cone; stigma capitate, minutely papillate, green in live plants. Fruit a globose berry, 8-10(-20) mm in diameter, fleshy, dark green at maturity, 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 at apex, spaced 0-0.5(-1.0) mm apart, reflexed and becoming woody, dropping with mature fruits, not persistent; fruiting calyx not markedly accrescent but the lobes slightly elongating in fruit, the tube less than 1 mm long, the lobes (4.0-)4.5-5.5(-8.0) mm long, 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 x =24 ( Moscone 1992; Moyetta et al. 2013).

Distribution

(Figure 54 ). Native to the Americas with an amphitropical distribution between temperate South and North America. Introduced outside its native range in Europe, South Africa and Australia, probably with agricultural seed or wool waste.

Ecology.

Grows across a wide range of habitats, along road sides, sandy soils, in cultivations and in salt plains; between sea level and 2,300 (-2,900) m elevation in its native range, between sea level and 1,800 m in the introduced range.

Common names.

Australia: cut-leaf nightshade ( Walsh and Entwisle 1999), three-flowered nightshade ( Harden 1993); United Kingdom: small nightshade ( Stace 2010).

Uses.

None recorded; a weed of agriculture.

Preliminary conservation status

( IUCN 2016). Solanum triflorum is a weedy species that is invasive where introduced; it has a large EOO and can be assigned a preliminary status of LC (Least Concern; Table 7 ). The EOO, based on native range only, is also very large (19,993,876 km2), mainly due to the disjunct distribution between North America and southern South America.

Discussion.

Solanum triflorum is a weed of agricultural areas and appears not to spread aggressively based on collection numbers (see Knapp 2018). It is easily distinguished from other species in the Old World by its usually deeply lobed leaves that are often pinnatifid, but are sometimes only shallowly lobed (see van Ooststroom 1966; description of var. Solanum triflorum dentatum ), the usual presence of a bracteole in the inflorescence, very narrowly elliptic buds and berries with> 30 stone cells per berry.

In its native range, S. triflorum has a very large range of berry sizes; most introduced material has larger berries, but it is possible we have not seen material that has the smaller berry size from the Old World. There is also large variation in the indumentum and leaf shape in S. triflorum in its native range ( Subils 1989), some of which can be seen in the Old World material. This variation is likely caused by environmental factors and has no taxonomic relevance ( Subils 1989).

The varieties of S. triflorum described by Hooker (1837) were described from plants collected on the second Franklin Expedition of 1825-1827, whose principal botanist was John Richardson and assistant botanist Thomas Drummond. William J. Hooker saw the material while he was in Glasgow and two specimens at E were originally from there; the material from the expedition eventually came to the Natural History Museum (BM), but some is also held at K. We have selected as the lectotype of var. Solanum nigrum minus the sheet labelled "S. trifidum β” (= var. Solanum nigrum minus ) at E (E00526685) which has tiny plants and consider the small plants (also labelled “β” and on a sheet together with larger plants with a separate label) at BM (BM000934744) as isolectotype material. The sheet at K (K001159656) has both small and large plants mounted on it and is labelled "S. triflorum α & β”, but here the small plants are labelled" α”; we think these are mislabelled at K and are actually part of what Hooker was recognising as var. Solanum nigrum minus (his β). We select the large plants (BM000934745) as the lectotype of var. Solanum triflorum majus and assign the large plants on the K sheet (K001159656) as isolectotype material.

Selected specimens examined.

Australia. New South Wales: Queanbeyan, Queanbeyan Stockyards, 5 Feb 1931, Calvert KEW-84 (CANB, PERTH); Murrumbidgee River , Dew’s Corner 4 km S of Fairvale Homestead, 8 May 1987, Canning & Lloyd 6421 (AD, CANB, NSW); Gundaroo Creek , 4.7 km N of Gundaroo on rd to Gunning, 23 Mar 1991, Lepschi 542 (AD, CANB, K); Fyshwick, Australian Capital Territory, 7 Apr 1991, Lepschi 555 (CANB, HO); Mid-Western Regional, Bylong district , 11 Oct 1953, McKee 654 (MEL); Armidale Dumaresq, Armidale, 10 Jan 1973, Williams s.n. (NE) ; Queensland: Southern Downs, Stanthorpe, 24 Feb 1954, Alison s.n. (BRI); Southern Downs , Ballandean, 23 Jan 1974, Booth s.n. (BRI); Southern Downs , 8 km of Ballandean, 20 Feb 1974, Swann s.n. (BRI); Southern Downs , Wallangarra, 22 Dec 1958, Taylor s.n. (BRI) ; South Australia: Region 9, Murray , 28 May 1972, Alcock 3939 (AD, CORD); Culburra, c. 80 km NW of Bordertown, 12 Feb 1963, Fry s.n. (E); Keith, 5 Apr 1965, Kain s.n. (K); NSW Finley, 30 Jan 1975, Symon 9807 (AD, MO, NSW); Murray Bridge, northern fenceline of Monarto Conservation Park, 6 Feb 1998, Taylor 291a (AD, MEL) ; Tasmania: Pitt Water, Seven Mile Beach Protected Area , 31 Mar 2006, Baker 1707 (CANB, HO, MEL); Clarence, Seven Mile Beach, 3 Apr 2000, Buchanan 15695 (AD, HO) ; Victoria: East Gippsland , 6 km NW of Mt Deddick, 17 Apr 1981, Forbes & Rees 909 (AD, MEL); Banyule, nr Montpelier Billabong, 7 Mar 2011, Lynch s.n. (CANB, HO, MEL) ; Western Australia: Wickepin, 17 Jan 1949, Eccles s.n. (PERTH)Beverley, 25 km E of Brookton, Hambly s.n. (PERTH); Steerdale, John Forrest rd, Hopetoun, 3 Dec 1997, Hill s.n. (PERTH); Swan, Midland, 12 mi E of Perth, Jan 1968, Moir s.n. (AD); Brookton , Williams & Williams s.n. (PERTH) .

Austria. Wien: Wien, Muellplatz Laaerberg , 1 Sep 1969, Forstner & Melzer s.n. (W) .

Belgium. Flanders: De Panne , 15 Aug 1976, Goetghebeur 2605 (H, MO); Gent, 7 Aug 1983, Goetghebeur & Pauw De 5252 (H, MO, UT); Westhoek, 15 Aug 1976, Goetghebeur 8626 (W); Antwerp, Linkeroever, Middenvijver, 22 Sep 2009, Wieringa 6785 (BM, W) .

France. Hauts-de-France: Pas-de-Calais, Camiers, au NW d’Etaples, chemin conduissant a la plage Saint Gabriel, 30 Oct 1973, Lambinon et al. 1461 (BM, H) .

Germany. Nordrhein-Westfalen: Niederrhein, Emmerich , 20 Oct 1929, Krüger 700 (W) .

Morocco. Oriental: Oued Charef, au nord de Ain-Benimathar, 21 Jun 2008, Calvo et al. 2501 (MA) .

Netherlands. Zuid Holland: Isle of Rosenburgh, De Beer, 26 Aug 1948, van Hattum 4073 (MO); Isle of Rozenburg , De Beer, 26 Aug 1948, van Hattum 4073 (K); Goeree, Havenhoofd, 13 Aug 1977, Podlech 8624 (BM, H, MO) .

Romania. Moldova , Distr. Covurlui, stationem viae ferreae Fulgeresti, 6 Sep 1922, Petruscu & Borza 2465 (W) .

South Africa. Eastern Cape: Morgendal , 10 Feb 1960, Acocks 21049 (EA) .

Sweden. Götaland: Skåne, Malmö, Sep 1906, Hylmö s.n. (BM) .

Tunisia. Gabes: Gabes, Djebel Dirra , Apr 1909, Pitard s.n. (MA) .

United Kingdom. England: nr Hartley, Wintney Hants , 17 Aug 1949, Hodge 4288 (K) ; Essex, Barking , 17 Oct 1953, Lousley s.n. (BM) ; Northumberland, Holy Island , 5 Sep 1936, Hutton s.n. (K) ; Northumberland, Holy Island , 13 Sep 1955, Lousley s.n. (BM) ; Suffolk, Woodbridge , 14 Sep 1932, Milne-Redhead & Airy Shaw 1834 (K) ; Scotland: Possil , Glasgow, 11 Sep 1918, Grierson 955-18 (K) ; Wales: Gwynedd, Caernarfonshire , Dinas Dinlle, Herrington s.n. (BM) ; Cardiff, Cardiff, 22 Aug 1925, Smith s.n. (BM) .

Figures

Figure 52. Solanum triflorum A Flowering habit B Fruiting habit C Flowering branch D Detail of adaxial leaf surface E Detail of adaxial leaf surface F Bud G Flower H Fruit (A, C, F-G Donat 55; B, D-E, H Baker 577). Drawing by R. Wise.

Figure 53. Solanum triflorum 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.

Figure 54. Distribution of Solanum triflorum in its non-native range in the Old World.