Based on an unpublished illustration of Leschenault collection kept in the Node-Véran collection in Montpellier (lectotype, designated here: Service du Patrimoine Historique de l’Université de Montpellier Node-Véran, Sol. Tab. 47 [MPU028534]); Indonesia. East Java: Blambangan [Sumberwaru, Badjulmati], T. Horsfield s.n. (epitype, designated here: BM [BM000886121]).

Scandent shrub to 2 m, armed. Young stems terete, brownish grey, very sparsely stellate-pubescent and prickly, the stellate trichomes porrect, sessile to subsessile, the rays (4-)5–8, 0.1–0.25 mm long, the midpoints to 0.15 mm long, the prickles to 7 mm long, to 8 mm wide at base, curved, deltate, laterally flattened, pale yellow, glabrous; bark of older stems dark brownish grey, glabrescent. Sympodial units difoliate, the leaves geminate, usually similar in size. Leaves simple, the blades (4.5-)7–11 cm long, (1.5-)3–5 cm wide, ca. 2 times longer than wide, elliptic to ovate, chartaceous, slightly discolourous; adaxial and abaxial surfaces sparsely to very sparsely stellate-pubescent and usually with at least some prickles, the stellate trichomes porrect, sessile to subsessile, the rays 6–8, 0.1–0.25 mm long, the midpoint to 0.25 mm long, usually as long as the rays, the prickles 0–10(-12) per leaf side, mostly inserted on the midvein, to 9 mm long, to 2 mm wide at base, straight or slightly curved at the tip, awl-shaped, conical, pale yellow, glabrous; major veins 3–4 pairs drying dark; base attenuate to truncate; margins shallowly to deeply lobed, the lobes 1–3 on each side, 0.5–2.5 cm long, broadly deltate, apically rounded, the sinuses extending up to 2/3 of the distance to the midvein; apex rounded to acute; petiole 0.5–1.8 cm long, 1/10–1/6 of the leaf blade length, sparsely stellate-pubescent with porrect, subsessile trichomes denser at the very base, with 0–2 prickles like those of the blades. Inflorescences leaf-opposed or apparently lateral and borne between leaf pairs, 2–4 cm long, unbranched to up to 6 times branched, with 15–50+ flowers; axes sparsely to very sparsely stellate-pubescent, unarmed; peduncle 1–2(-2.5) cm long, with 0–1 prickles like those of the leaves and stems; pedicels 4–7 mm long, erect, articulated at the base, very sparsely stellate-pubescent, unarmed; pedicel scars spaced 1–5 mm apart. Flowers 5-merous, apparently all perfect. Calyx 1.75–2 mm long, campanulate, pubescent with sessile porrect stellate trichomes like those of the stems, unarmed, the lobes 0.25–0.5 mm long, deltate, apically acute. Corolla 0.5–1 cm in diameter, white to pale lilac, stellate, lobed nearly to the base, the lobes 4–5 mm long, ca. 1 mm wide, narrowly deltate to linear, reflexed at anthesis, densely stellate-pubescent abaxially, the trichomes porrect, sessile, the rays 4–6, 0.1–0.2 mm long, the midpoints the same size than the rays or to 0.25 mm long. Stamens slightly unequal; filament tube < 0.5 mm long; free portion of the filaments almost equal, 0.5–1.25 mm long; anthers unequal, three of the five 4.5–5 mm long and two 3–4 mm long, all 0.5–0.75 mm wide, glabrous, connivent, tapering, poricidal at the tips, the pores not lengthening to slits with age. Ovary conical, minutely glandular-puberulent; style ca. 5.5 mm long, slender, curved at the apex, glabrous; stigma capitate, minutely papillate. Fruit a globose berry, 6–50+ per infrutescence, 3–5 mm in diameter, the pericarp shiny, red when mature, glabrous; fruiting pedicels 0.8–1.2 cm long, ca. 0.5 mm in diameter at the base, tapering to a slightly enlarged apex, woody, spreading, unarmed; fruiting calyx lobes slightly expanding to 1.5 mm long, ca. 1/5 the length of the mature fruit, deltate to lanceolate, unarmed. Seeds 6–9 per berry, 3.5–4 mm long, 3–3.5 mm wide, flattened-reniform, orange-brown, the surface minutely pitted, the testal cells pentagonal in outline.

Figure 1. 

A Lectotype of Solanum graciliflorum, illustration Sol. Tab. 47 [MPU028534] made by T.F. Node-Véran (1773–1852). Reproduced with permission of the Université de Montpellier – Herbier MPU (Service de Patrimoine Historique); copyright Université de Montpellier – Herbier MPU (SPH) B Epitype of Solanum graciliflorum, T. Horsfield s.n. [BM000886121] C Lectotype of Solanum poka, illustration Sol. Tab. 55 [MPU028527] made by T.F. Node-Véran (1773-1852). Reproduced with permission of the Université de Montpellier – Herbier MPU (Service de Patrimoine Historique); copyright Université de Montpellier – Herbier MPU (SPH) D Epitype of Solanum poka, T. Horsfield s.n. [BM000886306].

The few known collections were flowering and fruiting between May and August.

(Fig. 2) Known from the islands of Java, Bali, Sulawesi and Ambon (Indonesia); growing in forest understory; elevation not recorded on any herbarium material we have seen. The records (as S. athroanthum) from the island of Luzon in the Philippines (Merrill 1912, Merrill 1923) are based on misidentifications of specimens of S. trilobatum L.

Figure 2. 

Distribution of Solanum graciliflorum and Solanum poka in the Malay Archipelago. Geographical information for these collections can be found in the data supplement to this article (Suppl. material 1).

Data Deficient (DD); known only from seven collections, several of which are of uncertain localities. Solanum graciliflorum has not been re-collected since the first half of the 20^th century, indicating it is certainly of conservation concern. Recollection of this species and exploration of the type locality are priorities.

Indonesia. Bali: Perepat Agoeng, 21 Jul 1934, de Voogd 2177 (A); Gorontalo: North Celebes, Jun 1875, Riedel s.n. (K); Java: sin loc., 1802, Horsfield 15 (K); West Java, Bogor, Anonymous s.n. (K); Malaku: “Malay Archipelago, Dawalore [Ambon, Dawa-lour]”, Aug 1883, Riedel s.n. (K).

Solanum graciliflorum is a poorly known species represented by very few collections that presents a combination of morphological features that makes it readily recognisable among tropical Asian spiny solanums. It is superficially similar to S. cyanocarphium Blume, a sympatric species that is distributed across the Sunda Shelf region, and to S. retrorsum Elmer, that occurs mainly in the Philippines. Solanum graciliflorum can be distinguished from both of them by its much sparser indumentum, stout, deltate stem prickles (rather than slender and awl-shaped), and tiny, delicate flowers (hence the species epithet) that are clustered in dense, many-flowered inflorescences. Molecular data show that S. cyanocarphium and S. graciliflorum are not closely related; S. graciliflorum is nested within the Sahul-Pacific clade while S. cyanocarphium is an unresolved species of uncertain affinities (see Aubriot et al. 2016).

Solanum graciliflorum is the type of section Graciliflorum (Dunal) Seithe, a section partly based on the informal grouping made in Dunal’s (1852) treatment of Solanum in Candolle’s Prodromus. In Seithe’s (1962) circumscription, section Graciliflorum included 14 species with stellate trichomes and acicular prickles coming from various region of the world (e.g., S. bahamense L. from the Caribbean archipelago, S. nienkui Merr. & Chun from Southeast Asia, S. paniculatum L. from South America, S. stelligerum Sm. from Australia). Symon (1981, 1985) extended the circumscription of the section with the addition of 27 additional species (10 from Australia and 17 from New Guinea), expressing at the same time serious doubts about its coherence. Symon’s concerns echoed those expressed in Whalen’s systematic treatment of the spiny solanums (Whalen 1984). In this first-ever attempt to include spiny solanums into a morphologically based phylogenetic framework, Whalen did not regard section Graciliflorum as a natural group and placed members of the section as defined by Seithe (1962) into several of his informal groups (e.g., S. bahamense in the ‘Solanum bahamense group’, S. paniculatum in the ‘Solanum torvum group’, S. stelligerum in the ‘Solanum ferocissimum group’). With limited sampling and knowledge of Old World taxa, Whalen did not clarify the identity of S. graciliflorum, the type species of the section, and included it in his ‘Unusual species group’ as a possible synonym of the widespread tropical Asian species S. violaceum Ortega. He considered S. athroanthum to be different from S. graciliflorum, and placed the former into his ‘Solanum dunalianum group’ [= Solanum section Dunaliana (Bitter) Symon pro parte], a group of 20 species distributed across the Malayan archipelago, Australia and the South Pacific that were characterised by lack of broad-based prickles on mature growth, entire leaves with glabrate abaxial surfaces, inflorescences with tightly spaced hermaphroditic flowers, and juicy red berries (Whalen 1984). More recently McClelland (2012) proposed a narrower circumscription of sect. Dunaliana, reducing it to six species and excluding S. graciliflorum (as S. athroanthum) on the basis of its deeply lobed leaves with prickles on the principal veins and its slightly unequal anthers (versus entire to shallowly lobed non-prickly leaves and always equal anthers for all species he recognized as belonging to sect. Dunaliana). Instead he suggested a close relationship between S. graciliflorum and S. nienkui, a Southeast Asian species that also displays anisandry. Recent molecular phylogenetic analysis of tropical Asian spiny solanums incorporating representatives of sections Dunaliana and Graciliflorum (including S. dunalianum Gaudich. and S. graciliflorum) showed S. graciliflorum to be sister to the Philippine endemic S. lianoides Elmer (Aubriot et al. 2016). Both species are prickly vines, but S. lianoides differs from S. graciliflorum by its denser leaf indumentum, entire leaves and larger flowers. Both species are closely related to S. dunalianum (Aubriot et al. 2016), a result consistent with Whalen’s (1984) treatment of S. graciliflorum (as S. athroanthum; see Aubriot et al. 2016 for discussion) but not with McClelland’s (2012) hypothesis of relationships.

In the protologue Dunal referred to an illustration made by Node-Véran, ‘Dun. Suppl. 7. Sol. Mss. tab. 4.’, an orthographic error for ‘Dun. Suppl. Sol. Mss. tab. 47.’ according to the sequence of figure numbers and to the caption on the illustration in Montpellier. We were unable to find any herbarium material matching the illustration in either P or MPU, although Dunal later (Dunal 1816, 1852) cited Leschenault as the collector of the material he had seen. We designate the unpublished illustration of Node-Véran as the lectotype because it is the only extant original material we have identified to date. We have also designated here an epitype specimen that best matches Node-Véran’s illustration, and that corresponds to a collection made in the same geographical area as the lost type specimen (i.e. the island of Java in Indonesia) in order to secure the application of the name (Art. 9.8, McNeill et al. 2012).

Dunal (1852) based his description of S. athroanthum on Zollinger 2907 in “hb. DC.”. There are two specimens of Zollinger 2907 in G-DC; we select the more complete of these as the lectotype. The locality data for Zollinger’s collections are often not written on all duplicates; for Zollinger 2907 locality data are only found on P00368940.

Based on an unpublished illustration of Leschenault collection kept in the Node-Véran collection in Montpellier (lectotype, designated here: Service du Patrimoine Historique de l’Université de Montpellier, Node-Véran, Sol. Tab. 55 [MPU028527]); Indonesia. Java: sin. loc., T. Horsfield s.n. (epitype, designated here: BM [BM000886306]).

Shrubs to 3 m, armed. Young stems terete, black to dark brownish, moderately stellate-pubescent, usually densely prickly distally, sometimes unarmed, the stellate trichomes porrect, sessile or variously stalked, the stalks to 0.2 mm long, the rays (4-)5–8, 0.1–0.25 mm long, the midpoints reduced to globular glands; prickles to 3.5 mm long, to 2.5 mm wide at base, straight, awl-shaped to deltate, conical, pale yellow, glabrescent; bark of older stems brownish gray, sparsely stellate-pubescent. Sympodial units difoliate, the leaves geminate. Leaves simple, the blades 11–24 cm long, 4–13 cm wide, ca. 1.5–3 times longer than wide, elliptic to broadly ovate, chartaceous, slightly discolorous; adaxial surface moderately stellate-pubescent with porrect, sessile and less often variously stalked trichomes, the stalks to 0.1 mm long, the rays 4–8, 0.1–0.4 mm long, the midpoints to 0.25 mm long; abaxial surface moderately stellate-pubescent with trichomes like those of the adaxial surface, but more often stalked; prickles 0–6 per leaf side, to 6 mm long, to 1.5 mm wide at base, straight or slightly curved at the tip, awl-shaped, conical, pale yellow, glabrous; major veins 6–8 pairs drying yellow; base shortly attenuate to truncate; margins entire or shallowly to deeply lobed, the lobes 1–5 on each side, 0.5–5 cm long, rounded to apically acute, the sinuses extending up to 2/3 of the distance to the midvein, deltate; apex acute; petiole 1.5–4 cm long, 1/10–1/5 of the leaf blade length, densely stellate-pubescent with porrect, sessile trichomes like those of the blades, with 0–5 prickles like those of the stems. Inflorescences apparently lateral or leaf opposed, 2–5 cm long, unbranched to up to 2 times branched, with ca. 5–20 flowers, moderately to densely stellate-pubescent, unarmed; peduncle 0.5–1.5 cm long, with 0–1 prickles; pedicels 0.5–1.2 cm long, erect, articulated at the base, densely stellate-pubescent, unarmed; pedicel scars spaced 2–4 mm apart. Flowers 5-merous, apparently all perfect. Calyx 4–7 mm long, campanulate, moderately stellate-pubescent, densely stellate-pubescent on the midvein, unarmed, the lobes 3–5 mm long, the lower part deltate and abruptly constricting to an elongate acumen, the acumen 3/4 the total lobe length, the abaxial surface more or less strongly keeled along the midvein. Corolla 1–2 cm in diameter, white, lobed for ca. 1/2–2/3 of the way to the base, the lobes 5–8 mm long, 2–3.5 mm wide, deltate, spreading at anthesis, densely stellate-pubescent abaxially on parts exposed in bud. Stamens equal; filament tube < 0.5 mm long; free portion of the filaments 0.75–1.5 mm long; anthers 5–6.5 mm long, ca. 0.75 mm wide, connivent, tapering, poricidal at the tips, the pores not lengthening to slits with age. Ovary conical, minutely glandular-puberulent; style 0.6–1 cm long, slender, curved at the apex, with few scattered hairs at the tip; stigma capitate, minutely papillate, stellate-pubescent. Fruit a globose berry, 8–18 per infrutescence, 0.8–1.5 cm in diameter, the pericarp smooth, bluish green when young turning to dark greyish yellow, glabrous; fruiting pedicels 1.2–2.5 cm long, ca. 1–1.5 mm in diameter at the base, ca. 2–3 mm in diameter at the apex, woody, erect, unarmed; fruiting calyx lobes not expanding. Seeds 100–200 per berry, ca. 1.75–2 mm long, 1.5–1.75 mm wide, flattened reniform, pale yellowish, the surface minutely pitted, the testal cells sinuate in outline.

Flowering and fruiting throughout the year.

(Fig. 2) Widely distributed in the Malay Archipelago, from western Sumatra to the Maluku Islands and across Sulawesi, northwards to the Talaud islands; growing in open woodland, forest edges, degraded vegetation, usually on limestone or volcanic rocks; 0–1600 m elevation.

Least Concern (LC); EOO > 100,000 km² and AOO > 10,000 m² (see Moat 2007 for explanation of measurements). Although the EOO and AOO measurement indicate a status of least concern, the few collections coupled with the profound transformation in lowland Indonesian habitats where S. poka is found (Margono et al. 2014) suggest that the species is a priority for recollection and reassessment.

Indonesia. Central Sulawesi: Banggai regency, Luwuk District, Bunta Subdistrict, Sumber Agung, Gunung Hek, Sungai Hek, Cabang Tiga, 980 m, 27 Feb 2004, Hendrian et al. 964 (E, L); Sigi Regency, near the river S of Tongoa, 650 m, 17 Mar 1981, Johansson et al. 419 (K, L); Java: sin. loc., Horsfield s.n. (BM); sin. loc., Horsfield 786 (BM); Malaku: Central Maluku Regency, Wae Mamahala, 1330 m, 11 Nov 1937, Eyma 2166 (A, L); Central Maluku Regency, Seram Utara District, Manusela National Park, along a trail from Wae Puo to Kali, Ili area, south of Sawai, 830–1230 m, 23 Jan 1985, Kato et al. C-5431 (A, L); East Seram Regency, Bula District, Luman, 15 km south of Bula, 10–20 m, 26 Feb 1985, Kato et al. C-7942 (L); North Sulawesi: Minahasa Regency, Mt. Soputan, 1080 m, 11 Oct 1973, de Vogel 2504 (L); Minahasa Regency, Tondano, 1840, Forsten s.n. (L); Minahasa Regency, 25 Apr 1895, Koorders 18035B (L); Minahasa Regency, 20 m, 28 Apr 1895, Koorders 18037B (L); Talaud Islands Regency, Pulau Karakelang, bank of Kuala Bahewa, 30 m, 3 May 1926, Lam 2772 (K, L); South Sulawesi: Gowa Regency, Lombasang, 1000 m, 26 May 1921, Bunnemeyer 11732 (K, L); Gowa Regency, Lombasang, 1100 m, 31 May 1921, Bunnemeyer 11813A (L); Bantaeng Regency, Bonthain [Bantaeng], 1500 m, 12 Jun 1921, Bunnemeyer 12117 (L); Kolaka Regency, Baula, 150 m, 26 Dec 1909, Elbert 3224 (L); Enrekang Regency, Enrekang District, Latimojong Mts., in valley 3 km. south west of Bunte Tjejeng and south east of Rantelemo, 1490 m, 14 Nov 1969, Sands 477 (A, E, K); Timor: sin loc., 1882, Forbes 3806 (BM, L); West Sumatra: Agam Regency, Mt. Singgalang, 1600 m, 29 May 1918, Bunnemeyer 2786 (A, L).

Solanum poka was long ignored after its first publication (Dunal 1814). It has not been included in classical floristic treatments of Java (Hasskarl 1848, Backer 1965, van Steenis et al. 2006) or Sumatra (Miquel 1862). It was mentioned by Miquel (1856) and Koorders (1912), but both authors merely repeated Dunal’s original description, without referring to any specimens. In Koorders’s (1918) botanical report on the flora of northeastern Sulawesi he lists several widespread and common species (e.g., S. lycopersicum L., S. melongena L., S. torvum Sw., S. tuberosum L.) as well as two shrubby Solanum species for which he did not provide names (“Solanum spec. A” and “Solanum spec. B”). Two previously undetermined Koorders collections of S. poka from northeast Sulawesi (Minahasa Regency) in April 1895 (Koorders 18035B and Koorders 18037B, both L) correspond to S. poka. It is possible that these two collections correspond to one (or both) of Koorders’ (1918) unnamed species, but since he provided no descriptions or specific localities this is difficult, if not impossible, to ascertain.

Based on morphology, S. poka belongs to the Torva clade (sensu Stern et al. 2011), with its straight prickles, many flowered inflorescences and corollas with abundant interpetalar tissue (see Fig. 1b). This hypothesis is corroborated by the molecular data (Aubriot et al. 2016). Solanum poka is sister to a clade composed of four native Old World species (Solanum dammerianum Lauterb. & K.Schum, S. peikuoense S.S.Ying, S. pseudosaponaceum Blume, S. torvoideum Merr. & L.M.Perry) with which it forms a strongly supported group, the ‘Old World torvoids’ sensuAubriot et al. (2016). Morphologically, S. poka most closely resembles S. pseudosaponaceum, a widespread species from Taiwan and southern China to Indonesia, but differs in having denser indumentum on the adaxial leaf surface, more numerous straight prickles on the upper stems, fewer, larger flowers with elongate strongly keeled calyx lobes, and much larger fruits. Flowers of S. pseudosaponaceum are lilac or purplish-white while those of S. poka are always described on labels as white.

In the protologue Dunal referred to an illustration made by Node-Véran, ‘Dun. Suppl. 7. Sol. Mss. tab. 55’, but cited no herbarium material. Similarly to the situation of S. graciliflorum, we were unable to find any herbarium material matching the illustration in either P or MPU, although Dunal later (Dunal 1816, 1852) cited Leschenault as the collector of the material he had seen. We designate the unpublished illustration of Node-Véran as the lectotype because it is the only extant original material we have identified to date. We designate here an epitype specimen from Java, the cited type locality, (Horsfield s.n., BM000886306) that best matches Node-Véran’s illustration, particularly with respect to the diagnostic characters for S. poka; leaf shape, prickle shape and calyx lobe morphology.

We have only seen three specimens of S. poka from Java, the cited type locality, all collected by Thomas Horsfield, an American physician who collected on Java contemporaneously with Leschenault in the early part of the 19^th century (McNair 1942, Van Steenis-Kruseman and Van Steenis 1950). Solanum poka is, however, rather broadly distributed across the Malay Archiplago, with the distribution centred on Sulawesi and the surroundings islands (Malaku Islands, Talaud Islands) (Fig. 2). Thorough examination of the extensive holdings in Indonesia (particularly those of the Bogor Botanical Garden Herbarium, BO) and, given the historically extensive natural habitat loss recorded for Java (Margono et al. 2014), additional collecting are both needed to better understand the distribution of S. poka.

Dunal (1852) cited the herbarium name ‘S. quercifolium Banks’ taken from a specimen in BM collected by Joseph Banks in Java as part of his treatment of S. poka. Examination of this sheet (BM000886238) shows it belongs to S. pseudosaponaceum.