Solanum insanum L., Mant. 1: 46. 1767.

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

19. Solanum insanum L., Mant. 1: 46. 1767.

Figs 1F , 3E , 4A , 33

Solanum undatum Lam., Tabl. Encycl. 2: 22. 1794. Type. Mauritius. Sin. loc., "Insula Franciae", J. Martin s.n. (lectotype, designated by Vorontsova and Knapp 2016, pg. 197: P-LA (P00357695, Morton neg. 8392]).

Solanum trongum Poir., Encycl. (Lamarck) 4: 308. 1797. Type. Indonesia. Malaku: “Amboina” [Ambon Island] (no specimens cited; lectotype, designated by Merrill 1917, pg. 463, as “type”: "Trongum Solanum agreste spinosum", Rumphius, Herb. Ambion. 5: 240, t. 86, f.1. 1747).

Solanum gula Buch.-Ham., Trans. Linn. Soc. London 14(2): 267. 1824. Type. India. Karnakata: Kowdhalli "Caudhully [protologue - Mysore]", Oct 1800, J. Buchanan-Hamilton s.n. (lectotype, designated here: BM [BM000900233]).

Solanum himalense Dunal, Prodr. [A. P. de Candolle] 13(1): 300. 1852. Type. India. "Sivala & sub Himala" [protologue: In Himalae et Sivalae montibus altit. 4600 ped., Edgeworth, pl. exs. Ind. n. 116], M.P. Edgeworth 116 (holotype: MPU [MPU981115]).

Solanum indicum Nees var. pubescens Dunal, Prodr. [A. P. de Candolle] 13(1): 310. 1852. Type. [India]. Sin. loc., N. Wallich s.n. [Wallich Catal. 2626g] (lectotype, designated here: G-DC [G00130396]; isolectotype: K-W [K001116650 pro parte, R-hand two stems]).

Solanum melanocarpum Dunal, Prodr. [A. P. de Candolle] 13(1): 355. 1852, nom. illeg. superfl. Type. Based on Solanum insanum L. (cited in synonymy; "Nomen Solanum insanum mutavi, quia adeo non Solanum insanum videtur ut potius fructus edules credibilius sunt, quemadmodum nomina Solanum insanum et melongean, saepissime fuerunt confusa" [I changed the name Solanum insanum because it does not seem harmful, the fruits are probably edible, and Solanum insanum and Solanum melongena were very often getting confused]).

Solanum melanocarpum Dunal var. atropurpureum Dunal, Prodr. [A. P. de Candolle] 13(1): 356. 1852. Type. Indonesia. Java: sin. loc., H. Zollinger 698 (lectotype, designated here: G-DC [G00131525]; isolectotypes: G [G00301647], G-DC [G00131526, as Zollinger 698b], P [P00379566, P00379567]).

Solanum undatum Lam. var. aurantiacum Dunal, Prodr. [A. P. de Candolle] 13(1): 359. 1852. Type. Cultivated, sin. loc., Anonymous s.n. (lectotype, designated by Vorontsova and Knapp 2016, pg. 198: G-DC [G00131519]).

Solanum undatum Lam. var. violaceum Dunal, Prodr. [A. P. de Candolle] 13(1): 359. 1852. Type. Mauritius. Sin. loc., L. Bouton s.n. (lectotype, designated by Vorontsova and Knapp 2016, pg. 198: G-DC [G00131506]; isolectotype: G [G00131504]).

Solanum trongum Poir. var. divaricatum Dunal, Prodr. [A. P. de Candolle] 13(1): 361. 1852. Type. Sri Lanka. “Trinquemalay”, A.A. Reynaud s.n. (lectotype, designated here: P [P00049887]).

Solanum trongum Poir. var. rumphii Dunal, Prodr. [A. P. de Candolle] 13(1): 361. 1852, nom. illeg. Type. Described using same material as S. trongum Poir. (should be var. Solanum trongum trongum )

Solanum trongum Poir. var. sinuatopinnatifidum Dunal, Prodr. [A. P. de Candolle] 13(1): 361. 1852, nom. illeg. Type. Based on Solanum trongum Poir. [sensu Blume 1826] (should be var. Solanum trongum trongum )

Solanum trongum Poir. var. tongdongense Dunal, Prodr. [A. P. de Candolle] 13(1): 361. 1852. Type. Myanmar. "Tong dong", 7 Jan 1827, N. Wallich s.n. [Wallich Catal. Burm. 135] (lectotype, designated here: G-DC [G00131531]; isolectotype: G-DC [G00131371]).

Solanum album Lour. var. gaudichaudii Dunal, Prodr. [A. P. de Candolle] 13(1): 361. 1852. Type. Vietnam. Sin. loc., 1839, “Cochinchina”, C. Gaudichaud s.n. (holotype: G-DC [G00131563]).

Solanum cyanocarphium Blume var. obtusangulum Dunal, Prodr. [A. P. de Candolle] 13(1): 362. 1852. Type. Indonesia. Java: Sin. loc., 1837, J.C. von Hoffmannsegg 119 (lectotype, designated here: G-DC [G00131561]).

Solanum cumingii Dunal, Prodr. [A. P. de Candolle] 13(1): 363. 1852. Type. Philippines. Sin. loc., H. Cuming 443 (lectotype, designated here: G [G00076245]; isolectotypes: BM [BM000778205], E [E00190694], G [G00076246, G00076247], K [K000195960, K000195961], L [L0003628], LE, ME [MEL2444029], P [P00578602, P00578613], W [acc. # 0000622, acc. # 1889-0084423]).

Solanum immane Hance ex Walp., Ann. Bot. Syst. 3(1): 165. 1852. Type. China. Hongkong: "Hong Kong", [Herb.] H.F. Hance 860 (no specimens or herbaria cited; lectotype, designated here: BM [BM000942450]).

Solanum melongena L. var. insanum Prain, Bengal Pl. 746. 1903. Type. Based on Solanum insanum L.

Solanum mirikense C.R.Mukhop., J. Indian Soc. Bot. 72(1-2): 185. 1993. Type. India. West Bengal: Darjeeling, Mirik, 1700 m, 5 Oct 1985, C.R. Mukhopadhyay 428A (holotype: CAL [CAL0000018719]).

Solanum melongena L. var. cumingii (Dunal) J.Samuels, Proc. XV EUCARPIA Mtg. 258. 2013. Type. Based on Solanum cumingii Dunal

Solanum melongena L. subsp. insanum Banfi, Galasso & Bartolucci, Nat. Hist. Sci. 15(1): 19. 2017. Type. Based on Solanum insanum L.

Type.

India. Gujarat: Surat, Anonymous s.n. (lectotype, designated by Hepper and Jaeger 1985, pg. 389: LINN [acc. # 248.29]) .

Description.

Erect shrub, to 1 m tall, armed. Stems erect, terete, prickly, moderately stellate-pubescent to glabrescent; prickles to 8 mm long, to 5 mm wide at the base, straight, flattened, yellow-orange, glabrous; pubescence of stalked porrect-stellate trichomes, the stalks to 0.2 mm long, the rays 6-12, 0.2-0.4 mm long, the midpoints ca. same length as the rays or elongated to 1 mm; new growth densely stellate-pubescent, light brownish in dry material; bark of older stems grey to brown, glabrescent. Sympodial units difoliate, the leaves not geminate. Leaves simple, moderately lobed, the blades 2.5-12 cm long, 1.3-8 cm wide, ca. 1.5 times longer than wide, ovate, chartaceous, concolorous to weakly discolorous, armed with 2-20 prickles on both surfaces, these yellow-tan or purple-tinged; adaxial and abaxial surfaces yellow-green, moderately pubescent, with porrect-stellate trichomes, sessile or stalked, the stalks to 0.2 mm, the rays 5-8, 0.2-0.7(-1) mm long, the midpoints ca. same length as the rays; major veins 3-5 pairs; base truncate, sometimes obtuse; margins lobed, the lobes 2-3 on each side, 0.5-1.2 cm long, broad-deltate, apically rounded, the sinuses less than halfway to the midrib; apex rounded to acute; petiole 0.7-3 cm long, 1/4-1/3 of the leaf blade length, unarmed or prickly with 1-5 prickles, moderately stellate-pubescent to glabrescent, the pubescence with stellate-porrect trichomes like those of the stems. Inflorescences 2.5-3.5 cm long, apparently terminal or lateral, unbranched, with 1-3 flowers, 1 flower open at any one time, moderately to densely stellate-pubescent with porrect trichomes like those of the stems, unarmed; peduncle 0-13 mm long, unarmed or with a few prickles; pedicels 0.8-2.5 cm long, ca. 1 mm in diameter at the base, ca. 2 mm in diameter at the apex, erect, unarmed or with a few scattered prickles, densely stellate-pubescent with porrect trichomes like those of the inflorescence axes, articulated at the base; pedicel scars spaced 1-2 mm apart. Buds ovoid, poorly exserted from the calyx before anthesis. Flowers 5(-6)-merous, heterostylous and the plants andromonoecious, with the lowermost flower(s) long-styled and hermaphrodite, the distal flowers short-styled and staminate. Calyx with the tube 4-5 mm long, campanulate, the lobes 4-6 mm long, 2-2.5 mm wide, deltate, apically acute, unarmed or with 1-15 prickles, densely stellate-pubescent with porrect trichomes like those of the pedicels. Corolla 1.8-2.5 cm in diameter, mauve or white, almost rotate with abundant interpetalar tissue, lobed ca. 1/4 of the way to the base, the lobes ca. 7 mm long, ca. 10 mm wide, broadly deltate, spreading at anthesis, glabrous to sparsely stellate-pubescent adaxially with porrect-trichomes mostly on the midvein and the tips, densely stellate-pubescent abaxially with variously stalked porrect trichomes. Stamens equal; anthers 4-5 mm long, ca. 1 mm wide, tapering, yellow, glabrous, poricidal at the tips, the pores directed distally, not elongating to slits with drying; filament tube ca. 1.5 mm long, glabrous; free portion of the filaments 1-2 mm long, glabrous. Ovary conical to ovoid, stellate-pubescent and glandular in the upper 1/4; style 2-3 mm in short-styled flowers, 5-7 mm long in long-styled flowers, moderately stellate-pubescent in the lower 1/2; stigma capitate or occasionally somewhat bilobed, the surfaces minutely papillose. Fruit a globose berry, 1 per infructescence, 1.5-3 cm in diameter, dark green with pale green and cream markings when young, yellow at maturity, the pericarp smooth, glabrous; fruiting pedicels 1.5-2.2 cm long, 1.5-3 mm in diameter at the base, 4-5 mm in diameter at the apex, unarmed or with a few stout prickles, woody, pendulous; fruiting calyx lobes elongating to 9-15 mm long, 1/4-1/3 the length of the mature fruit, reflexed, with 2-30 prickles. Seeds ca. 50-150 per berry, 2.4-2.8 mm long, 1.8-2.2 mm wide, flattened-reniform, orange-brown, the surface minutely pitted, the testal cells with sinuate margins. Chromosome number: n = 12 ( Meyer et al. 2012, as S. undatum ).

Distribution

(Fig. 34 ). Solanum insanum is widely distributed in India and southeastern Asia (east to the Philippines) and is also found as far west as Madagascar and Mauritius (possibly introduced there from Asia for its medicinal properties).

Ecology and habitat.

Solanum insanum is a plant of degraded scrubland and secondary vegetation and occurs from sea level to ca. 500 m elevation.

Common names and uses.

Cambodia. trâp rôm nhong ( Hul and Dy Phon 2014), trôp (Collard 56), trôp som nhon (Collard 32), China. ye qie ( Zhang et al. 1994); Hainan: ngou ke tzi (Lei 392). India. Andhra Pradesh: challa mulaga (Foulkes 83); Chattisgarh: anpa, jangli bhata (Kumar CNH-15565); Rajasthan: bhutkataiya [Hindi] ( Singh 1991, as S. incanum ); Tamil Nadu: thalamoolagah, nullamoolaga (Wight 1573 Ab); Uttar Pradesh: bari bhatkatanja (Bell 863), jangli bengan (Sarin NC-5079). Indonesia. Borneo: terong nasi (Ambriansyah 687); Java: terong-glate (Hoffmansegg 119). Laos. mok kua kim (Spire 914), mok khma lê (Pottier 263). Malaysia/Singapore. tĕrong (with various qualifiers, Burkill 1935). Malaysia. Sabah: soguntung [Rungus] (Jones 152). Singapore. terong nyonya (Corner SFN-37775). Sri Lanka. Uva: ela batu [Sinhala] (Hepper & Silva 4719). Vietnam. heng khôm (Spire 1081), cà co [Annamite] (Pierre 706), la plonh [Moi] (Poilane 85), blon blok (Schmid 1608).

Preliminary conservation status

( IUCN 2019). Least Concern (LC). EOO (10,914,652 km2, LC); AOO (1,052 km2, VU). Solanum insanum is a widespread weedy species of disturbed areas and agricultural margins. It was not considered of conservation concern in an assessment of eggplant wild relatives ( Syfert et al. 2016).

Discussion.

Solanum insanum is the wild progenitor of the cultivated eggplant (aubergine; S. melongena ) and readily crosses with that species ( Davidar et al. 2015; Mutegi et al. 2015), thus complicating its recognition in the past (see references and discussion in Knapp et al. 2013; Ranil et al. 2016). We have chosen to recognise the two as distinct species rather than as infraspecific taxa (e.g., Lester and Hasan 1991; Daunay and Hazra 2012) because cultivated and wild plants are on distinct evolutionary trajectories. Wild plants are subject to natural selection, while cultivated plants are commensal with human beings. We recognise that this can lead to difficulties in identifying individual specimens, particularly those from old collections where details of provenance are not clear.

Distinguishing S. insanum from the cultivated S. melongena can be difficult in the absence of fruits. Keys in previous publications ( Knapp et al. 2013; Ranil et al. 2016) can be used for identification, but in general specimens we assign to S. insanum are pricklier, with smaller flowers and fruit, and more ruderal than those we assign to S. melongena . Local cultivars of S. melongena in tropical Asia can be especially difficult to distinguish from S. insanum .

Solanum incanum L. is another species with which S. insanum is frequently confused, and the name S. incanum has frequently been used in the past literature for all "wild eggplants" (see Knapp et al. 2013 for the history of nomenclature of the wild eggplant relatives both in Asia and Africa). Solanum incanum occurs from across northern Africa and the Middle East to Pakistan; we have seen no specimens identifiable as S. incanum from the area treated here. The many specimens labelled “Punjab” from early collections in "British India" have all proved to be from Pakistan, not from adjacent India, but S. incanum potentially occurs near border areas. Solanum incanum is a more densely pubescent plant than is S. insanum , with long-stalked trichomes that dry a distinctive yellow colour (see Vorontsova and Knapp 2016 for a description) and plants are generally pricklier, although this character is extremely variable within these taxa; it generally grows in much drier habitats than does S. insanum . Crossability of these two taxa is not known, confusion over the identity of accessions used in crossing studies (e.g., Daunay and Hazra 2012) means that this remains to be tested.

Mill (2001: 1050) suggested S. mirikense , treated as a synonym of S. insanum here, was synonymous with S. mauritianum Scop., an introduced member of the Brevantherum clade. He had not seen the type specimen in CAL, which clearly places it as a synonym of S. insanum .

The sole element cited in Poiret’s (1797) description of S. trongum is the treatment and illustration of "Trongum Solanum agreste spinosum" in Rumphius (1747), and Merrill (1917) effectively lectotypified the name with this illustration by stating “type”. The illustration is of a very spiny plant, which Rumphius (1747) stated was wild and described as "ingrata et Melongena spinosa herba" (ungrateful and spiny herb).

The name S. gula has been placed in the synonymy of various spiny solanums over the years (R.N. Lester, m.s.). In the protologue Buchanan-Hamilton (1824) states "I found it first in my journey to Mysore, where it is called Gula, and in 1806 I gave specimens, a drawing and a description of it to Sir J.E. Smith". No specimens are extant in the Smith herbarium at the Linnean Society of London, but the drawing held there (see https://linnean-online.org/168572/) is clearly of S. insanum and has been annotated as such in James Edward Smith’s hand. A specimen at BM (BM000900233) is labelled " Solanum gula B" by Buchanan-Hamilton and also has an annotation of " Solanum insanum L" in Smith’s hand. This is certainly the specimen mentioned in the protologue and is here designated as the lectotype of S. gula .

In the protologue of S. indicum var. pubescens Dunal (1852) cited two Wallich catalogue numbers, "2629 a, ex parte" and "2626 g", and stated that he had seen specimens in G-DC and "herb. Wall.". The catalogue number 2629 is a mixture of various species (including S. pubescens ), so we have chosen the G-DC sheet of Wallich cat. 2626g (G00130396) as the lectotype because it is unambiguous, it matches the protologue and it was clearly seen by Dunal. The specimen labelled "Wallich cat. 2626G" at Kew in the Wallich Herbarium (K00116650) is a mixture of two taxa; the left-hand stem corresponds to S. multiflorum and the two right hand stems to S. insanum , only these two right-handstems are considered isolectotype material here.

Two of the four infraspecific taxa described by Dunal (1852) under S. trongum were described with no specimens cited, the only references are to previously published works and the descriptions are copied from those. Var. Solanum trongum sinuato-pinnatifidum cites only "Blum. bijdr. 700, karondong, nomen Indicum"; this is a reference to Blume’s (1826: 702, an error in citation of page) S. trongum Poir., where the name karondong is stated, but no material or localities cited. We consider this homotypic with S. trongum and do not recognise Blume’s treatment of S. trongum as a distinct species. We consider var. Solanum trongum rumphii to be illegitimate because Dunal (1852) cited the same type as that of S. trongum ; Dunal appears to be using this as the “typical” variety. Both of the other varieties had specimens cited. Two Wallich catalogue numbers (burm. 135, 2628E) were cited in the protologue of S. trongum var. tongdongense , both of which were seen in G-DC ("v.s. h. DC"). We have selected one of the duplicates of the best preserved of these, Wallich cat. iter. Burm. 135, at G-DC as the lectotype. The protologue of var. Solanum trongum divaricatum cites two collections (Perottet s.n. from “Pondicherry” [India], Reynaud s.n. from “Ceylon”) both seen in Paris. Both collections are S. insanum ; we have selected the Reynaud specimen from Sri Lanka (P00049887) as the lectotype because it has both flowers and fruits.

Two collections from Java, Hoffmansegg 119 in G-DC and Roemer s.n. in G ("herb. Boiss.") were cited in the protologue of S. cyanocarphium var. obtusangulum ; we have selected the first of these as the lectotype of the name because the number makes it unambiguous. Although Java collections are attributed to him (as here), Hoffmansegg never visited Java ( van Steenis-Kruseman 1985); plants in his herbarium were collected for him there by a friend.

Of the many duplicates of Cuming 443, the sole collection cited in the protologue of S. cumingi , we have selected the one in G cited by Dunal (1852, as "herb. Boiss.") that bears an annotation label in hand as the lectoytpe (G00076245).

The protologue of S. immane cites no specimens or herbaria, but the name (and probably the description) is taken from Henry Fletcher Hance’s unpublished manuscript describing Chinese plants ( Walpers 1852). Walpers worked in Berlin, and any specimens he saw are likely to have been destroyed. Of the specimens we have seen that could correspond to original material or duplicates of the Hance collection used to describe S. immane , only one specimen at BM (Herb. Hance 860, BM000942450) matches both the protologue description and the collection locality; we have selected this as the lectotype for the name. Other duplicates of Hance 860 in P are either from different localities (i.e., P00049897, from "prope Cantonem") or represent different species (e.g., P00055662 = S. violaceum ).

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 3. Diversity of inflorescences and flowers in tropical Asian spiny solanums A lax, spreading inflorescences and stellate flowers of Solanum violaceum (Sampath Kumar et al. 126945, India) B condensed, recurved inflorescences and stellate flowers of S. multiflorum (Sampath Kumar et al. 126950, India) C inflorescences and large stellate flowers of S. involucratum (field photograph, unvouchered, Vietnam) D inflorescences and stellate flowers of S. pubescens with unequal stamens, one long and recurved (Sampath Kumar et al. 126956, India) E large rotate flower of S. insanum with abundant interpetalar corolla tissues (Sampath Kumar et al. 126918, India) F many flowered inflorescence and infructescence of S. pseudosaponaceum (field photograph, unvouchered, Philippines) G many flowered inflorescences of S. torvum; flowers with well-developed interpetalar corolla tissues (Suksathan et al. PS 3815, Thailand) H small stellate flowers of S. viarum (Sampath Kumar et al. 126944, India). Photograph credits: A, B, D, E, H X. Aubriot C M. Nuraliev F D. Tandang G 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 33. Solanum insanum L. A herbarium specimen collected in India in 1994 (Chorley & Bharatan 3, BM 000013803) B habit (Meeboonya et al. RM 257) C detail view of a hermaphroditic flower (Meeboonya et al. RM 251, Thailand) D detail view of an inflorescence with an opened staminate flower (Meeboonya et al. RM 257, Thailand) E detail view of an immature fruit (Meeboonya et al. RM 277, Thailand). Photograph credits: A CC-BY, © copyright The Trustees of the Natural History Museum, London B-E X. Aubriot.

Figure 34. Distribution of S. insanum.