Solanum giganteum Jacq., Collectanea 4: 125. 1791.

Aubriot, Xavier & Knapp, Sandra, 2022, A revision of the " spiny solanums " of Tropical Asia (Solanum, the Leptostemonum Clade, Solanaceae), PhytoKeys 198, pp. 1-270 : 1

15. Solanum giganteum Jacq., Collectanea 4: 125. 1791.

Figs 1A , 25

Solanum niveum Vahl, Symb. Bot. 2: 41. 1791. Type. South Africa. “Cape”, sin. loc., C. Thunberg s. n. (holotype: UPS-THUNB [microfiche 1036, no. 5209]).

Solanum farinosum Wallich in Roxburgh, Fl. Ind. (Carey & Wallich ed.) 2: 255. 1824. Type. India. “Babobad”, Herb. Heyne s. n. (lectotype, designated by Vorontsova and Knapp 2016, pg. 163: K [K000658975]).

Solanum farinaceum Griffith, Itin. Pl. Khasyah Mts. 111. 1848. Type. Bhutan. Dewanagiri, 1837, W. Griffith 148 (no specimens cited; no original material found at K).

Solanum giganteum var. tenuifolium Dunal, Prodr. [A. P. de Candolle] 13(1): 259. 1852. Type. India. Tamil Nadu: Madras State, Nilgiri Hills [ “Nellighery”], Nedaubetta, 1840, G. S. Perrottet 520 (lectotype, designated by Vorontsova and Knapp 2016, pg. 163: P [P00049799]; isolectotype: P P00049800]).

Solanum giganteum var. longifolium Dunal, Prodr. [A. P. de Candolle] 13(1): 259. 1852. Type. India. Sin. loc., Anonymous s. n. [Wallich cat. 2610] (lectotype, designated by Vorontsova and Knapp 2016, pg. 163: G-DC [G00145950]).

Solanum bequaertii De Wild., Repert. Spec. Nov. Regni Veg. 13: 141. 1914. Type. Democratic Republic of the Congo. Katanga: Shaba Prov., Lubumbashi [Elisabethville], 2 Mar 1912, J. Bequaert 219 (holotype: BR [BR0000008994356]; isotype: BR [BR0000008993045]).

Solanum sordidescens Bitter, Bot. Jahrb. Syst. 57: 260. 1921. Type. Tanzania. Lindi: Kilwa-Kiwindje Distr., Tschumo, Matumbi Mts., 250 m, Jul 1903, W. Busse III 3097 (lectotype, designated by Vorontsova and Knapp 2016, pg. 164: EA [EA000001237]; isolectotypes: BM [BM001070317], BR [BR0000006495435]).

Solanum seretii De Wild., Miss. Em. Laurent, 1: 439, tab. 122. 1907. Type. Democratic Republic of the Congo. Orientale: Kisangani, Bima to Bambili, 25 Oct 1905, F. Seret 166 (holotype: BR [BR0000008993465]; isotype: BR [BR0000008993168]).

Solanum muansense Dammer, Bot. Jahrb. Syst. 48: 243. 1912. Type. Tanzania. Mwanza: Mwanza, May 1892, F. L. Stuhlmann 4504 (type: B?, destroyed; no duplicates found).

Type.

Cultivated in Vienna , original material from South Africa, Cape of Good Hope, N.J. Jacquin s.n. (lectotype, designated by Vorontsova and Knapp 2016, pg. 163: W [acc. # 0000608]; isolectotype: W [acc. # 0000609]) .

Description.

Erect shrub to small tree, to 4 m tall, armed or occasionally unarmed. Stems erect, terete, prickly, densely stellate-pubescent; prickles to 7 mm long, to 5 mm wide at the base, straight, occasionally curved, deltate, orange-brown to almost white, glabrescent to stellate-pubescent in the lower 3/4; pubescence of stalked multangulate-stellate trichomes, the stalks to 0.7 mm long, the rays 10-25, 0.05-0.2 mm long, the midpoints ca. same length as the rays; new growth densely stellate-pubescent with a pale whitish grey pubescence; bark of older stems glabrescent to densely stellate-pubescent, light brown. Sympodial units plurifoliate, the leaves usually not geminate, if geminate the leaves of a pair differing slightly in size but not in shape, in addition often with small stipule-like leaves along the stem. Leaves simple, entire, the blades 12-40 cm long (if geminate the minor blades usually ca. 3 cm long), (3-)4-13 cm wide, ca. 2.5 times longer than wide, elliptic, chartaceous, strongly discolorous, unarmed; adaxial surface drying green-brown to red-brown, glabrescent; abaxial surface drying light grey-green, moderately to densely stellate-pubescent with multangulate stalked trichomes, the stalks to 0.3 mm long, the rays 8-25, 0.1-0.2 mm long, the midpoints ca. same length as the rays; major veins 8-12 pairs, the finer venation visible on both surfaces; base cuneate; margins entire; apex acute to acuminate; petiole 1.5-5.5 cm long, 1/8-1/4 of the leaf blade length, weakly to densely stellate-pubescent with multangulate trichomes like those of the blades, unarmed. Inflorescences 5-13(-20) cm long, apparently terminal or lateral, several times branched, with 30-150 flowers, 10-30 flowers open at any one time, weakly to densely stellate-pubescent with multangulate trichomes like those of the stems, unarmed; peduncle 20-60 mm long, unarmed; pedicels 0.4-1.5 cm long, 1-1.2 mm in diameter at the base, 2-2.5 mm in diameter at the apex, erect to recurved, unarmed, moderately to densely stellate-pubescent with multangulate trichomes like those of the inflorescence axes, articulated at the base; pedicel scars unevenly spaced 1.5-10 mm apart. Buds ovoid, the corolla strongly exserted from the calyx tube before anthesis. Flowers 4-5-merous, apparently all perfect. Calyx with the tube 2.5-3 mm long, conical, the lobes 0.5-2.5(-4) mm long, 1.3-2.2 mm wide, deltate, apically obtuse to acute, unarmed, moderately to densely stellate-pubescent abaxially with multangulate trichomes like those of the rest of the plant, these often deciduous. Corolla 0.8-1.5 cm in diameter, usually mauve, sometimes white, stellate, lobed 2/3-3/4 of the way to the base, the lobes 3.5-6 mm long, 1.5-2.5 mm wide, deltate, spreading or not opening fully, moderately stellate-pubescent abaxially, the trichomes porrect, sessile or stalked, the stalks to 0.1 mm, the rays 8-15, 0.05-0.15 mm long, the midpoints ca. same length as the rays. Stamens equal; anthers 2.5-3 mm long, ca. 1 mm wide, connivent, tapering, yellow, glabrous, poricidal at the tips, the pores not elongating to slits with drying; filament tube ca. 1 mm long, glabrous; free portion of the filaments 0.4-0.8 mm long, glabrous; Ovary conical, glabrous; style 0.45-0.65 cm long, slender, straight or gently curved, glabrous; stigma small capitate. Fruit a globose berry, many per infructescence, 0.6-0.8 cm in diameter, the pericarp smooth, evenly green when young, bright red at maturity, glabrous; fruiting pedicels 0.8-1.6 cm long, 0.5-1.2 mm in diameter at the base, 1.2-2 mm in diameter at the apex, woody, erect, unarmed; fruiting calyx lobes not elongating, ca. 1/3 the length of the mature fruit, reflexed, unarmed. Seeds ca. 15-30 per berry, 2.3-2.9 mm long, 1.5-2.5 mm wide, flattened-reniform, dull yellow to orange-brown, the surface minutely pitted, testal cell margins sinuate. Chromosome number: not known.

Distribution

(Fig. 26 ). Solanum giganteum is a widespread species occurring from Sri Lanka and southern India and throughout eastern and southern Africa (but is absent from western Africa, see Vorontsova and Knapp 2016). It is recently being recorded as adventive in Australia (http://www.flora.sa.gov.au/) where it has not yet naturalised.

Ecology and habitat.

Solanum giganteum is a weedy species growing at the edges of forests and re-growth in clearings, disturbed areas, sometimes in rocky places or open grasslands; from sea level to 2,100 m elevation.

Common names and uses.

English common names for S. giganteum in large parts of India are red bitter berry or healing-leaf tree; other local names in India are kurti [Marathi], paintilkkakkoti, paintilikam, peyccuntai-p-palam [Tamil] ( Ved et al. 2016, envis.frlht.org); Kerala: cheruchunda ( Ved et al. 2016, envis.frlht.org); Tamil Nadu: sambal kilurai [Tamil] ( Matthew 1983); peyccundai, anaiccundai [Tamil] ( Nair and Nayar 1987), putharichunda, sambal kilurae [Tamil] ( Henry et al. 1987).

Solanum giganteum is planted as a shade tree and widely used medicinally in Africa for treatment of sores and ulcers ( Hutchings et al. 1996) and in folk medicine in India ( Ved et al. 2016).

Conservation status

( IUCN 2019). Solanum giganteum has been formally assessed as LC (Least Concern) due to its wide range and weedy nature and is so listed on the IUCN Red List (Botanic Gardens Conservation International (BGCI) and IUCN SSC Global Tree Specialist Group 2020).

Discussion.

Solanum giganteum is a common small tree in the understory of forests in India and Sri Lanka. Its large discolorous leaves accompanied by small stipule-like leaves along the stems, large bunches of bright red berries, deltate stem prickles and farinaceous white pubescence are distinctive and not shared by any other species in the region. The copious pubescence of multangulate trichomes is brittle and powdery, it easily detaches and rubs off leaves and stems, which is the origin of the specific epithet of the synonym S. farinosum . Solanum vagum of southern India and Sri Lanka is somewhat similar in overall appearance to S. giganteum , but has smaller, more lanceolate leaves, smaller inflorescences and less copious, non-deciduous pubescence (see description of S. vagum ). The broad stem prickles common in young plants of S. giganteum are absent in S. vagum . Populations of S. giganteum in India are generally found to have smaller leaves and inflorescences than those of Africa ( Vorontsova and Knapp 2016).

In analyses of phylogeny using molecular data S. giganteum is part of a strongly supported monophyletic group with African species S. anomalum Thonn., S. schimperianum A.Rich., S. schleibenii Werderm., S. schumannianum Dammer and S. somalense Franch. (Vorontsova et al. 2103). Also part of this group is the Indian species S. pubescens ( Aubriot et al. 2016a).

Solanum giganteum has a long history of cultivation, both in its native range as a shade tree and for fencing and outside of its range in European botanical gardens (see Vorontsova and Knapp 2016). Edmonds (2012) suggests it is native only to the Cape region of South Africa, but we feel this is a biased assessment due to its early introduction from there into Europe.

Specimens examined.

See Suppl. materials 1-3.

Figures

Figure 1. Diversity of habits and habitats for Solanum subgenus Leptostemonum in tropical Asia A Solanum giganteum, a small tree of the tropical forest understory in India and Sri Lanka (field photograph, unvouchered, India) B S. trilobatum, a scandent species in its typical habitat, along the road in mangrove area (Meeboonya et al. RM 245, Thailand) C S. lasiocarpum, an erect shrub found in disturbed and human inhabited areas where it is often cultivated (Meeboonya et al. RM 272, Thailand) D S. cyanocarphium, a creeper with decumbent stems in forest understory (field photograph, unvouchered, Vietnam) E S. camranhense, a scandent shrub endemic to the coastal dunes of South Vietnam (field photograph, unvouchered, Vietnam) F S. insanum, the wild progenitor of the brinjal eggplant usually found in degraded areas (Meeboonya et al. RM 305, Thailand). Photograph credits: A S. More B, C, F X. Aubriot; D M. Nuraliev E S. Hul.

Figure 25. Solanum giganteum Jacq. A herbarium specimen collected in ' Brooks' (Sri Lanka) in 1931 (Simpson 8890, BM 000900133) B detail of leaves and infructescence (field photograph, unvouchered, India) C detail of an inflorescence (field photograph, unvouchered, India). Photograph credits: A CC-BY, © copyright The Trustees of the Natural History Museum, London B P. Kumar C A. Prashant.

Figure 26. Distribution of S. giganteum.