Solanum trilobatum L., Sp. Pl. 188. 1753.

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

45. Solanum trilobatum L., Sp. Pl. 188. 1753.

Figs 1B , 2F , 4F , 74

Solanum acetosifolium Lam., Tabl. Encycl. 2: 24. 1794, as " acetosaefolium ". Type. India. Sin loc., P. Sonnerat s.n. (lectotype, designated here: P [P00055514]).

Solanum canaranum Miq., Hohen. Pl. Ind. Or. (Terr. Canara & Confin.) Exsicc. No. 740. 1847. Type. India. Karnakata: "prope Bettighery", Feb., R.F. Hohenacker 740 (lectotype, designated here: U [U.1740185]; isolectotypes: BM [BM000900314], K [K000014877]).

Solanum trilobatum L. var. griffithii C.B.Clarke, Fl. Brit. India [J. D. Hooker] 4: 237. 1883. Type. "Birma and Malay Peninsula", W. Griffith 5915 (lectotype, designated here: K [K000196631]).

Solanum griffithii (C.B.Clarke) Kuntze, Revis. Gen. Pl. 2: 454. 1891. Type. Based on Solanum trilobatum L. var. griffithii C.B.Clarke

Type.

"Habitat in India ", Anonymous s.n. (lectotype, designated by Deb 1980, pg. 51: LINN [acc. # 248.44]).

Description.

Scandent herbs or shrubs, to 2.5 m tall, armed. Stems erect or spreading, terete, moderately to densely prickly, glabrous or with a few scattered stellate trichomes; prickles to 6 mm long, to 5 mm wide at the base, deltate, markedly hooked, laterally flattened, pale yellow to brown, glabrous; pubescence of sessile to very short-stalked porrect-stellate trichomes, the rays 2-5, 0.1-0.25 mm long, the midpoints absent or to 0.25 mm long; new growth sparsely stellate-pubescent, glabrescent, light yellowish green in dry material; bark of older stems brownish, glabrous. Sympodial units apparently difoliate, the leaves geminate, usually similar in size. Leaves simple, more or less deeply lobed, the blades 2.5-6.5 cm long, 2-7.5 cm wide, ca. 1-1.5 times longer than wide, ovate to broadly ovate, somewhat fleshy, slightly discolorous, unarmed or with a few hooked prickles like those of the stems, per face; adaxial surface green, glabrous or with a few scattered porrect-stellate trichomes, the trichomes sessile to sub sessile, the rays 4-8, 0.1-0.25 mm long, the midpoints to 0.1 mm long; abaxial surface light-green, glabrescent, sometimes with a few (i.e., <10) porrect-stellate trichomes like those of the adaxial surface; major veins 3-5 pairs drying brown; base truncate to shortly attenuate; margins shallowly to deeply lobed, the lobes 1-2 on each side, 0.5-0.7 cm long, deltate, apically rounded, the sinuses extending up to 3/5 of the distance to the midvein; apex rounded; petioles 1.2-3 cm long, 1/2-2/3 of the leaf blade length, glabrescent, unarmed or with a few prickles like those of the stems. Inflorescences 1-6 cm long, apparently lateral, unbranched or forked, with ca. 3-11 flowers, only a few flowers open at any one time, glabrescent, unarmed; peduncle ca. 0.5 cm long, unarmed or a few prickles; pedicels 0.8-1.5 cm long, 0.8-1 mm in diameter at the base, 1.2-1.5 mm in diameter at the apex, erect, unarmed or with a few hooked prickles especially on the lower flowers, glabrescent, articulated at the base; pedicel scars spaced 0.4-1 cm apart. Buds ellipsoid, the corolla strongly exserted from the calyx before anthesis. Flowers 5-merous, apparently all perfect. Calyx with the tube 1.5-2 mm long, cup-shaped and somewhat keeled, the lobes 1-2 mm long, ca. 1 mm wide, narrowly deltate, apically acute, unarmed or with a few hooked to straight prickles, glabrous to sparsely stellate-pubescent with sessile porrect-stellate trichomes like those of the stems. Corolla 2-3 cm in diameter, purplish blue, stellate, lobed ca. 3/5-4/5 of the way to the base, the lobes 8-12 mm long, 2.5-7 mm wide, deltate to narrowly deltate, spreading at anthesis, sparsely to moderately stellate-pubescent abaxially on parts exposed in bud. Stamens equal; anthers 7-9 mm long, 1-1.5 mm wide, connivent, not tapering at anthesis, yellow, glabrous, poricidal at the tips, the pores directed distally, not elongating to slits with drying. Ovary globose, with minute glandular hairs; style 1.4-1.8 cm long, slender, curved at the apex, glabrous; stigma capitate, minutely papillate. Fruit a globose berry, 1 to several per infructescence, 0.7-1.2(-1.7) cm in diameter, red at maturity, the pericarp thin and shiny, glabrous; fruiting pedicels 1.2-2.6 cm long, ca. 1 mm in diameter at the base, 2-2.5 mm in diameter at the apex, erect to recurved, not markedly woody; fruiting calyx lobes slightly expanding to ca. 3 mm long, 1/5-1/3 the length of the mature fruit, deltate, not reflexed. Seeds ca. 16-47 per berry, 3-4 mm long, 2.5-3 mm wide, flattened-reniform, dull yellow, the surface minutely pitted, the testal cells pentagonal in outline. Chromosome number: n = 12, 2n = 24 ( Madhavadian 1968).

Distribution

(Fig. 75 ). Solanum trilobatum is widely distributed in tropical Asia; from South India and Sri Lanka to Indochina, and Java. The single collection from the Philippines (Loher s.n.) is from the railway station in Manila and is probably cultivated.

Ecology and habitat.

Solanum trilobatum grows in open areas or forest edges, on sand or limestone, close to coastal areas; often in open field or mangrove forest; from around sea level to 700 m elevation.

Common names and uses.

Cambodia. traob (Khmer, Hul 4774); India. Andhra Pradesh: uchinta (Venkanna 5562), usti (Raji 291); Karnataka: ullul ( Singh 1988); Odisha: ankaranti (Panigrahi EC-23792); Tamil Nadu: toundou valay [Tamul] (Commerson s.n.), thoothuvalai [Tamul] (Matthew 8323), tudulai [Tamul] (Mehen-Homji s.n.), thoodhuvalai [Tamul] (Narasimhan 624, Sampath Kumar et al. SC-126970), thudhuvaelai [Tamul] ( Matthew 1983), tuduvali [Tamul] ( Henry et al. 1987); West Bengal: kantikuri (Tribedi CNH-1435); Malaysia. priapantie (Curtis 858).

It is reported that in Thailand the plant is boiled to serve as a decoction for ulcerated throat (Collins 1380). Indian collectors reported that the fruits are edible and used as medicinal (Raji 291, Sengupta 145). In Penang (Malaysia) the root is used medicinally (Curtis 858). For the many uses in traditional medicine in India see section on Uses (pg. 18-20).

Preliminary conservation status

( IUCN 2019). Least Concern (LC). EOO (2,326,480 km2, LC); AOO (528 km2, VU). Widely distributed and likely to be protected by people as a plant of considerable medicinal importance, S. trilobatum is not of immediate conservation concern. Methods of collection for medicinal use, however, have not been assessed and if these are destructive this could be cause for concern.

Discussion.

Solanum trilobatum is widely distributed through India and Indochina. It was one of the first Asian spiny solanums to be described ( Linnaeus 1753) and was brought into cultivation in European botanical gardens in the late 18th century. It is a distinctive species with its rhomboidal to triangular leaves that are usually widest in the lower third, but has been confused with S. procumbens , a similarly scandent plant. Flowers of S. trilobatum are much larger than those of S. procumbens (2-3 cm in diameter versus 1-1.5 cm in diameter), with abundant interpetalar tissue; S. procumbens flowers are deeply stellate with narrow corolla lobes. The two species do not overlap in distribution.

No specimen labelled as S. acetosifolium has been found in the Lamarck herbarium (P-LAM), however in the French language column Lamarck (1794) cited "Indes Orient, Sonnerat" clearly indicating a collector. We have lectotypified S. acetosifolium with a specimen collected by Sonnerat labelled “Inde” in the general collection at Paris (P00055514).

In describing S. trilobatum var. griffithii , Clarke (1883) cited only "Griffith 5915"; we have selected the single specimen thus labelled (K000196631) as the lectotype.

The name S. canaranum was effectively published by being printed on herbarium labels that were distributed to herbaria before 1953 ( Turland et al. 2018, Art. 30.8); the name is also accompanied by a diagnosis attributed to Miquel. We have chosen the duplicate in Utrecht [U.1740185], where Friedrich Miquel worked ( Stafleu 1966), as the lectotype for this name.

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 2. Vegetative characters for tropical Asian spiny solanums A large and densely hairy repand leaf of S. lasiocarpum (Meeboonya et al. RM 287, Thailand) B small, pubescent, very shallowly lobed leaf of S. miyakojimense (field photograph, unvouchered, Taiwan) C entire, pubescent leaf of S. robinsonii (Nuraliev 3031, Vietnam) D glabrescent and deeply dissected leaf of S. virginianum (Sampath Kumar et al. 126968, India) E conical straight prickles on a pubescent young stem of S. hovei (field photograph, unvouchered, India) F strongly hooked prickles on a glabrous young stem and on the abaxial leaf surface of S. trilobatum (Meeboonya et al. RM 242, Thailand) G needle-like purple prickles on the adaxial leaf surface of S. cyanocarphium (field photograph, unvouchered, Vietnam) H pubescent young stem of S. barbisetum armed with prickles and bristles (Suksathan et al. PS 3832, Thailand). Photograph credits: A, B, D-F X. Aubriot C, G M. Nuraliev H D. Pedersen.

Figure 4. Diversity of fruits and seeds in tropical Asian spiny solanums A large oval fruit of Solanum insanum (Sampath Kumar et al. 126918, India) B condensed infructescence and small rounded fruits of Solanum hovei (field photograph, unvouchered, India) C large rounded hairy fruit of S. involucratum with strongly accrescent and spiny calyx (field photograph, unvouchered, Vietnam) D small rounded fruit of Solanum pubescens with elongated calyx lobes (Sampath Kumar et al. 126956, India) E rounded fruit of Solanum cyanocarphium with strongly accrescent and spiny calyx (field photograph, unvouchered, Vietnam) F small rounded fruit of S. trilobatum in transverse cut (Meeboonya et al. RM 242, Thailand) G rounded fruit and accrescent calyx of S. praetermissum in transverse cut (field photograph, unvouchered, Vietnam) H oval fruit of Solanum virginianum in transverse cut (field photograph, unvouchered, India). Photograph credits: A, B, D, F, H X. Aubriot C, E, G M. Nuraliev.

Figure 74. Solanum trilobatum L. A herbarium specimen collected in Thailand in 1966 (Larsen 1614, P 00055524) B habit (Meeboonya et al. RM 243, Thailand) C detail of the adaxial surface of a leaf blade (Meeboonya et al. RM 301, Thailand) D detail view of an open flower (Meeboonya et al. RM 245, Thailand) E detail view of an infructescence (field photograph, unvouchered, India). Photograph credits: A CC-BY, Museum national d'Histoire naturelle, Paris B-E X. Aubriot.

Figure 75. Distribution of S. trilobatum.