Solanum poka Dunal, Encycl. [J. Lamarck & al.] Suppl. 3: 768. 1814.

Aubriot, Xavier, Loup, Caroline & Knapp, Sandra, 2016, Confirming the identity of two enigmatic " spiny solanums " (Solanum subgenus Leptostemonum, Solanaceae) collected by Jean-Baptiste Leschenault in Java, PhytoKeys 70, pp. 97-110 : 101-104

Solanum poka Dunal, Encycl. [J. Lamarck & al.] Suppl. 3: 768. 1814. Fig. 1c, d

Solanum torvum Sw. var. scabrescens Miq. Fl. Ned. Ind. 2: 648. 1861. Type. Indonesia. Sumatra: sin. loc., F.W. Junghuhn s.n. (holotype: L [L0403917])

Type.

Based on an unpublished illustration of Leschenault collection kept in the Node-Véran collection in Montpellier (lectotype, designated here: Service du Patrimoine Historique de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

Description.

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.

Phenology.

Flowering and fruiting throughout the year.

Distribution and ecology.

(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.

Preliminary conservation status.

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 Solanum poka is found ( Margono et al. 2014) suggest that the species is a priority for recollection and reassessment.

Specimens examined.

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) .

Discussion.

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., Solanum lycopersicum L., Solanum melongena L., Solanum torvum Sw., Solanum 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 Solanum poka from northeast Sulawesi (Minahasa Regency) in April 1895 (Koorders 18035B and Koorders 18037B, both L) correspond to Solanum 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, Solanum 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, Solanum peikuoense S.S.Ying, Solanum pseudosaponaceum Blume, Solanum torvoideum Merr. & L.M.Perry) with which it forms a strongly supported group, the 'Old World torvoids’ sensu Aubriot et al. (2016). Morphologically, Solanum poka most closely resembles Solanum 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 Solanum pseudosaponaceum are lilac or purplish-white while those of Solanum 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 Solanum 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 Solanum poka ; leaf shape, prickle shape and calyx lobe morphology.

We have only seen three specimens of Solanum 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 19th 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 Solanum poka .

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

Figures

Figure 1. A Lectotype of Solanum graciliflorum, illustration Sol. Tab. 47 [MPU 028534] made by T. F. Node-Veran (1773 - 1852). Reproduced with permission of the Universite de Montpellier - Herbier MPU (Service de Patrimoine Historique); copyright Universite de Montpellier - Herbier MPU (SPH) B Epitype of Solanum graciliflorum, T. Horsfield s. n. [BM 000886121] C Lectotype of Solanum poka, illustration Sol. Tab. 55 [MPU 028527] made by T. F. Node-Veran (1773 - 1852). Reproduced with permission of the Universite de Montpellier - Herbier MPU (Service de Patrimoine Historique); copyright Universite de Montpellier - Herbier MPU (SPH) D Epitype of Solanum poka, T. Horsfield s. n. [BM 000886306].

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).