Solanum graciliflorum Dunal, Encycl. [J. Lamarck & al.] Suppl. 3: 763. 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 : 99-101

Solanum graciliflorum Dunal, Encycl. [J. Lamarck & al.] Suppl. 3: 763. 1814. Fig. 1a, b

Solanum athroanthum Dunal, Prodr. [A. P. de Candolle] 13(1): 208. 1852. Type. Indonesia. Java: [Prov. Banjinwanyne] "in sylvis prope Sukaradja" [Sukaraja], 1846, H. Zollinger 2907 (lectotype, designated here: G-DC [G003043306]; isolectotypes: G-DC [G00301684], BM [BM000778325], MPU [MPU012648], P [P00368939, P00368940, P00368941]).

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Based on an unpublished illustration of Leschenault collection kept in the Node-Véran collection in Montpellier (lectotype, designated here: Service du Patrimoine Historique de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-Veran , Sol. Tab. 47 [MPU028534]); Indonesia. East Java: Blambangan [Sumberwaru, Badjulmati], T. Horsfield s.n. (epitype, designated here: BM [BM000886121]) .

Description.

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.

Phenology.

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

Distribution and ecology.

(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 Solanum athroanthum ) from the island of Luzon in the Philippines ( Merrill 1912, Merrill 1923) are based on misidentifications of specimens of Solanum trilobatum L.

Preliminary conservation status.

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 20th century, indicating it is certainly of conservation concern. Recollection of this species and exploration of the type locality are priorities.

Specimens examined.

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) .

Discussion.

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 Solanum cyanocarphium Blume, a sympatric species that is distributed across the Sunda Shelf region, and to Solanum 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 Solanum cyanocarphium and Solanum graciliflorum are not closely related; Solanum graciliflorum is nested within the Sahul-Pacific clade while Solanum 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., Solanum bahamense L. from the Caribbean archipelago, Solanum nienkui Merr. & Chun from Southeast Asia, Solanum paniculatum L. from South America, Solanum 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., Solanum bahamense in the ' Solanum bahamense group’, Solanum paniculatum in the ' Solanum torvum group’, Solanum stelligerum in the ' Solanum ferocissimum group’). With limited sampling and knowledge of Old World taxa, Whalen did not clarify the identity of Solanum 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 Solanum violaceum Ortega. He considered Solanum athroanthum to be different from Solanum 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 Solanum graciliflorum (as Solanum 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 Solanum graciliflorum and Solanum 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 Solanum dunalianum Gaudich. and Solanum graciliflorum ) showed Solanum graciliflorum to be sister to the Philippine endemic Solanum lianoides Elmer ( Aubriot et al. 2016). Both species are prickly vines, but Solanum lianoides differs from Solanum graciliflorum by its denser leaf indumentum, entire leaves and larger flowers. Both species are closely related to Solanum dunalianum ( Aubriot et al. 2016), a result consistent with Whalen’s (1984) treatment of Solanum graciliflorum (as Solanum 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 Solanum 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.

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).