Solanum villosum Mill., Gard. Dict. ed. 8, no. 2. 1768

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 : 100-105

18. Solanum villosum Mill., Gard. Dict. ed. 8, no. 2. 1768 Figures 54 , 55

Type.9

Cultivated in Chelsea Physic Garden from "Barbados where it is supposed to grow naturally", Herb. Miller s.n. (lectotype, designated by Henderson 1974, pg. 54: BM [BM000942575]).

Description.

Annual to short lived perennial herbs, much branched at base and usually bushy in form, up to 0.5 m tall. Stems terete to ridged, green to purple, ascending, not hollow; new growth densely pubescent with eglandular and/or glandular, simple, spreading, uniseriate 3-10-celled trichomes 0.2-2.0 mm long; older stems glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple, 1.5 –5.0(– 10.0) cm long, 0.7 –2.5(– 6.5) cm wide, broadly to narrowly ovate to elliptic, green; adaxial surfaces sparsely to densely pubescent with spreading, simple, uniseriate eglandular and /or glandular trichomes like those on stem evenly along veins and lamina; abaxial surfaces more densely pubescent on veins and lamina; major veins 4-6 pairs; base acute to truncate, short-attenuate, often asymmetric; margins sinuate-dentate to rarely entire; apex acute; petioles 0.5 –3.0(– 4.5) cm long, pubescent with simple uniseriate glandular and/or eglandular trichomes like those on stems. Inflorescences 0.4-2.0 cm long, lateral, internodal, unbranched, with (2 –)3–5(– 8) flowers clustered at the tips (sub-umbelliform, young inflorescences only) or more commonly spaced along the rhachis, pubescent with spreading simple glandular and/or eglandular uniseriate trichomes like those of the stems; peduncle 0.4-1.5 cm long, straight; pedicels 4-7 mm long, 0.2-0.3 mm in diameter at the base and 0.4-0.5 mm in diameter at the apex, spreading, articulated at the base; pedicel scars spaced 0-1.0 mm apart. Buds globose, the corolla exserted ca. 1/5 from the calyx before anthesis. Flowers 5-merous, all perfect. Calyx tube 1.2-1.5 mm long, conical, the lobes 0.8-1.5 mm long, 0.5-0.8 mm wide, elliptic to triangular with obtuse thickened apices and paler (almost scarious) sinuses, pubescent with spreading simple uniseriate eglandular and/or glandular trichomes like those on stem. Corolla 8-15(-20) mm in diameter, white with a yellow-green central portion near the base and occasionally with purple stripes along lobe midveins abaxially, stellate, lobed 1/2 way to the base, the lobes 2.5-4.5 mm long, 2.0-3.5 mm wide, strongly reflexed at anthesis, later spreading, densely papillate-pubescent abaxially with simple uniseriate eglandular trichomes. Stamens equal; filament tube minute, pubescent with spreading uniseriate simple eglandular trichomes adaxially; free portion of the filaments 1.0-1.3 mm long, pubescent like the tube; anthers 1.8 –2.2(– 2.4) mm long, 0.5-0.7 mm wide, ellipsoid, yellow, poricidal at the tips, the pores lengthening to slits with age and drying. Ovary globose, glabrous; style 2.8-3.5 (-4.0) mm long, densely pubescent with 2-3-celled simple uniseriate trichomes in the lower half, exserted 0-1 mm beyond anther cone; stigma capitate, the surface minutely papillate, green in live plants. Fruit an ellipsoid berry, usually somewhat longer than broad, 8.5-10 mm long, 8.0-9.5 mm wide, (red-)orange to yellow at maturity, translucent, the pericarp shiny; fruiting pedicels 8-14 mm long, 0.4-0.5 mm in diameter at the base, 0.7-1.5 mm in diameter at the apex, strongly reflexed, becoming woody, spaced 1.0-2.0 mm apart not falling with the fruit, remaining on the plant and always persistent on older inflorescences; fruiting calyx not accrescent, the tube 1.0-1.5 mm long, the lobes 2.0-3.0 mm long and 1.0-2.0 mm wide, strongly reflexed in fruit. Seeds 20-40 per berry, 1.8-2.2 mm long, 1.5-1.7 mm wide, flattened and tear-drop shaped with a subapical hilum, brown, the surfaces minutely pitted, the testal cells pentagonal in outline. Stone cells absent, but occasionally 1-2 found in North African and Arabian material. Chromosome number: 2n =4 × =48 (see Särkinen et al. 2018).

Distribution.

(Figure 56 ) Solanum villosum is native to Europe where it is very common around the Mediterranean basin, the Arabian Peninsula to dry sub-tropical Asia, and eastern Africa (where it is cultivated for its fruit); the species is locally introduced but not persistent and not yet naturalised in North America.

Ecology.

In North America, the few collections occur at around sea level near ports and at higher inland elevations where details of cultivated versus adventive status have not been recorded on labels.

Common names.

United States of America. Hairy nightshade ( USDA Plants 2017; Correll and Johnston 1970, but unclear if this really refers to S. villosum or to a pubescent form of S. nigrum or to S. nitidibaccatum ).

Uses.

None recorded. In Africa the leaves and berries are eaten, the latter often by children (see Särkinen et al. 2018).

Preliminary conservation status ( IUCN 2017).

Least Concern (LC). Solanum villosum is a rare adventive species in North America; for conservation status in its native range see Särkinen et al. (2018).

Discussion.

Solanum villosum is an occasional non-native species to North America; the first known specimen was collected in 1899 by Curtiss from Pensacola, thought to have arrived in ships’ ballast from Europe ( D’Arcy 1974b). The species has clearly not persisted or spread in North America despite several introductions (as seen in the few specimen records from widely distant sites). The many synonyms for S. villosum (see Särkinen et al. 2018 for complete synonymy) reflect the broad morphological variation observed within the species, especially in its native range, where indumentum can range from nearly absent (the plants glabrous) to densely pubescent with eglandular and/or eglandular trichomes, and where cultivation and incipient domestication have resulted in a great range of inflorescence morphologies.

Solanum villosum can be easily distinguished from all other morelloid species in North America by its orange-red berries that are often slightly elongated in shape and that lack stone cells. We have been unable to verify with specimens the citation of S. villosum from Texas ( Correll and Johnston 1970); this is likely to be a misidentification. The Mexican species S. corymbosum , which also has orange-red berries, has branched inflorescences, minute flowers and berries with two large apical stone cells. All other species of the group in North America have rounded black or green berries. In bud and flower the calyx sinuses in S. villosum are much thinner than the lobes, and in dry specimens are white or transparent below the actual sinus, so that there appears to be a “window” in the calyx tube. In general aspect, plants are similar to those of S. retroflexum , but that species has matte purple berries with a distinct white glaucous bloom (also without stone cells, so herbarium specimens can be difficult to distinguish in the absence of good label information), and the leaves of S. retroflexum are more rhomboid in shape than those of S. villosum . Both of these introduced species are tetraploid and have glandular and eglandular forms in their native ranges.

The typification details for the 45 heterotypic Old World synonyms of S. villosum can be found in Särkinen et al. (2018).

Specimens examined.

See Suppl. materials 1 and 3.

Figures

Figure 54. Solanum villosum Mill. A Flowering habit B detail of adaxial leaf surface C detail of abaxial leaf surface D bud E dissected flower F fruiting habit G fruiting habit with dense indumentum H fruit (A-E Wood 2193 F Popov GP / 72 / 31 G Wood Y / 74 / 265). Drawing by R. Wise (previously published in " PhytoKeys 106 ").

Figure 55. Solanum villosum Mill. A Habit B inflorescence in densely pubescent plant C flowers and buds D immature infructescence E fully mature fruits F fully mature fruits showing reflexed calyx lobes (A Nijmegen accession 884750135 B Nijmegen accession 914750047 C Nijmegen accession A 34750061 D Nijmegen accession A 34750043 E Nijmegen accession A 14750048 F Nijmegen accession A 34750038). Photos by T. Saerkinen and G. van der Weerden (previously published in " PhytoKeys 106 ").

Figure 56. Distribution of Solanum villosum Mill.