Solanum pygmaeum Cav., Icon. 5: 23, tab. 439. 1799

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

12. Solanum pygmaeum Cav., Icon. 5: 23, tab. 439. 1799 Figures 37 , 38

Solanum pygmaeum Cav. var. hastatum Bonte ex Aellen, Ber. Schweiz. Bot. Ges. 50: 236. 1940.

Solanum pygmaeum Type. Argentina. Buenos Aires: Pergamino, J.A. de la Peña, 14 Jan 1925, L.R. Parodi 6107 (lectotype, designated here: BAA [BAA00004675]).

Solanum pygmaeum Cav. var. integrifolium Bonte ex Aellen, Ber. Schweiz. Bot. Ges. 50: 236. 1940.

Solanum pygmaeum Type. Switzerland. Basel-Stadt: Basel, Hof der Aktienmühle, Feb 1939, P. Aellen 3201 (lectotype, designated here: P [P03933622]; isolectotype: P [P03933624]).

Solanum pygmaeum Cav. var. sinuatodentatum Bonte ex Aellen, Ber. Schweiz. Bot. Ges. 50: 237. 1940, as “sinuato-dentatum”.

Solanum pygmaeum Type. Switzerland. Basel-Stadt: Basel, Hof der Aktienmühle, Feb 1939, P. Aellen 3202 (lectotype, designated here: P [P04477345]; isolectotypes: BM [BM001035970], P [P03933623]).

Solanum pygmaeum Cav. var. latifolium Bonte ex Aellen, Ber. Schweiz. Bot. Ges. 50: 237. 1940.

Solanum pygmaeum Type. Hungary. Györ: Oelfabrik, 1915 and 1918, S. Polgár s.n. (syntypes; no duplicates located, at BP?); Germany. Neuss: Oelfabrik, 1915, L. Bonte s.n. (syntype; no duplicates located); Germany. Emmerich: mit Oelfrucht, 1929, R. Scheuermann s.n. (syntype; no duplicates located).

Solanum pygmaeum Cav. var. suspensum C.V.Morton, Revis. Argentine Sp. Solanum 138. 1976.

Solanum pygmaeum Type. Argentina. Córdoba: Alta Córdoba, barrio de la ciudad de Córdoba, T. Stuckert 4713 (holotype: G [n.v.]; isotypes: CORD [CORD00004273, CORD00004274]).

Solanum deterrimum C.V.Morton, Revis. Argentine Sp. Solanum 138. 1976.

Solanum pygmaeum Type. Argentina. Buenos Aires: Sierra de la Ventana, 23 Feb 1944, H. Ruíz de Huidrobo 1332 (holotype: A [00077613]; isotypes: NY [00139129], S [acc. # 12-27773], SI [SI003308, SI003307]).

Type.

Argentina. Buenos Aires: "in Pampas de Buenos Ayres esquina de Ballesteros", Sep, L. Née, s.n. (lectotype, designated by Knapp 2007, pg. 200: MA [MA-476361!]; isolectotype: G [G00357891]) .

Description.

Perennial small upright herbs up to 30 cm tall, subwoody at base, perennating via underground rhizomes. Stems decumbent or ascending, delicate, terete or somewhat angled with ridges, not markedly hollow; new growth pubescent with simple, appressed, uniseriate, translucent, eglandular trichomes, these 1-6-celled, 0.2-0.5 mm long or nearly glabrous; older stems glabrous or glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple, 1.0-5.0 cm long, 0.5-3 cm wide, ovate to narrowly elliptic, pale green, concolorous, without smell; adaxial surface glabrous or sparsely pubescent along leaf lamina and margins with simple, uniseriate trichomes like those on stem; abaxial surface sparsely pubescent with similar trichomes but the pubescence denser along the midrib; major veins 3-4 pairs; base attenuate, decurrent on the petiole; margins sinuate to entire; apex acute to obtuse; petioles 0.5-1.7 cm long, with scattered simple, appressed, uniseriate eglandular trichomes like those on stem. Inflorescences 1-3 cm long, generally internodal, simple or rarely furcate, umbelliform to sub-umbelliform, with (2-)4-6 flowers clustered at the tip, glabrous or with scattered simple, appressed, uniseriate eglandular trichomes like those on stem; peduncle (1.3-)1.5-2.6 cm long, delicate; pedicels 6-13 mm long, 0.5-1 mm in diameter at the base, ca. 1 mm in diameter at the apex, straight and spreading, articulated at the base; pedicel scars spaced ca. 0-2.5 mm apart. Buds globose to broadly ovoid, the corolla strongly exserted from the calyx tube but only halfway exserted beyond the elongate and reflexed calyx lobes before anthesis. Flowers 5-merous, all perfect. Calyx tube (0.5-)1.7-2.0(-2.2) mm long, conical, the lobes 1.5-1.8 mm long, 0.7-0.9 mm wide, narrowly elliptic with long-acuminate to acute apices, glabrous to sparsely pubescent with simple uniseriate eglandular trichomes like those on stem. Corolla 9-16 mm in diameter, white to pale lilac with a yellow-green central portion near the base, stellate, lobed 1/2 way to the base, the lobes 5.0-6.7 mm long, ca. 3.0-3.5 mm wide, strongly reflexed at anthesis, later spreading, glabrous to sparsely pubescent abaxially with simple uniseriate trichomes like those of the stem but shorter. Stamens equal; filament tube minute; free portion of the filaments 1.0-1.2 mm long, adaxially pubescent with tangled uniseriate 4-9-celled eglandular trichomes to 0.5 mm long; anthers (3.0-)3.5-3.8 mm long, 0.7-1.0 mm wide, oblong-ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary globose, glabrous; style ca. 6.3 mm long, densely pubescent with (1-)2-3-celled simple uniseriate trichomes in the lower 4/5, exserted 1-2 mm beyond the anther cone; stigma capitate to clavate, bilobed, minutely papillate, green in live plants. Fruit a subglobose berry, 8-10 mm in diameter, greyish-green at maturity, the pericarp opaque and glaucous; fruiting pedicels 12-15 mm long, ca. 1 mm in diameter at the base and at the apex, deflexed and often somewhat curved, dropping with mature fruits, not persistent; fruiting calyx not accrescent, the tube ca. 1 mm long, the lobes 1.5-2 mm long, appressed against the berry. Seeds>50 per berry, 1.8-2.0 mm long, 1.2-1.4 mm wide, flattened and tear-drop shaped with a subapical hilum, pale yellow, the surfaces minutely pitted, the testal cells irregularly quadrate in outline. Stone cells 6-8, the 2 apical ones 1.5-2 mm in diameter, usually very closely paired, the rest equatorial and 1-1.2 mm in diameter, pale whitish-brown. Chromosome number: 2n =2x=24 (one individual with n=18 and chromosomal anomalies with supernumerary bivalents or univalents not segregating; Moscone 1992).

Distribution

(Figure 39 ). Native to central and coastal Argentina; a few specimens known from Europe arriving as seeds through wool shipments but these are not usually established as permanent populations.

Ecology.

Grows in sandy and clay soils, along rail road tracks and road sides; between 100 and 1,000 m elevation in its native range, but brought only sporadically to Europe and North America via wool shipments and trade to ports at sea level and has not naturalised widely.

Common names.

None recorded in Old World.

Uses.

None recorded.

Preliminary conservation status

( IUCN 2016). Solanum pygmaeum is widespread in its native range and can be assigned a preliminary status of LC (Least Concern; Table 7 ). Populations from the Old World are relatively ephemeral. Within the native range in South America, S. pygmaeum still has a relatively large EOO of 700,962 km2.

Discussion.

Solanum pygmaeum is only occasionally collected in Europe, usually associated with wool waste. It is a plant that spreads by underground stems, so it is surprising that it has not become established; we include the species here so that old herbarium specimens can be identified and so that the species can be spotted if it does become established as climate changes.

The species is easy to distinguish from all other morelloids occurring in Europe by its large flowers (anthers> 3mm long), narrowly elliptic calyx lobes (1.5-1.8 mm long) and rhizomatous habit. Leaves are quite variable in size, but are usually narrowly elliptic, less often wider in the lower half.

We have selected the P duplicates that were part of the “Société cénomane d’exsicccata” as the lectotypes of var. Solanum pygmaeum integrifolium and var. Solanum pygmaeum sinuatodentatum because they are well-preserved and have both flowers and young fruits. The lectotype we have selected for var. Solanum pygmaeum hastatum is in an Argentinian herbarium (see best practice as outlined in Smith and Figueiredo 2011) and we have been unable as yet to trace original material of var. Solanum pygmaeum latifolium .

Selected specimens examined.

France. Provence-Alpes-Côte d’Azur: Hyères, Fleming 306 (BM).

United Kingdom. England: Cornwall, Phillack Towans, Hayle , 12 Sep 1929 , Foggitt s.n. (BM); Greater London, Winchmore Hill , 9 Sep 1920 , Herb. Hall s.n. (BM); Greater London, Edgware , 22 Aug 1950 , Hill s.n. (BM); Greater London, Southall , 14 Aug 1945 , Kent s.n. (BM); Greater London, Hanwell , 3 Sep 1947 , Kent & Sandwith 3423 (K); Middlesex , 18 Aug 1945 , Lousley 4710 (BM); Hayle Towans, West Cornwall, 21 Sep 1929 , Melville & Smith 2922 (BM, K); Norfolk, Blickling , 3 Sep 1921 , Robinson s.n. (BM).

Figures

Figure 37. Solanum pygmaeum. A Habit B Flowering branch C Calyx D Dissected calyx, adaxial surface E Flower F Dissected flower G Stamen, dorsal view H Stamen, ventral view I Gynoecium J Fruit K Seed (A-K Bernardello 476). Drawing by L. Ribulgo.

Figure 38. Solanum pygmaeum A Habit B Flowering branch C Dissected flower D Developing fruits (A-D Chiarini 1341). Photos by F. Chiarini.

Figure 39. Distribution of Solanum pygmaeum in its non-native range in the Old World.