Solanum dunalianum Gaudich., Voy. Uranie 448. 1828.

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

12. Solanum dunalianum Gaudich., Voy. Uranie 448. 1828.

Fig. 20

Solanum pulvinare Scheff., Ann. Jard. Bot. Buitenzorg 1: 39. 1876, as " pulvinaris ". Type. Indonesia. West Papua: Ajambori, near Doré [Dorei Bay], J.E Teijsmann s.n. [7854] (lectotype designated by Symon 1985, pg. 129: BO [acc. # 1324393]; isolectotype: MEL [MEL0104159]).

Solanum dunalianum Gaudich. var. lanceolatum Witasek, Repert. Spec. Nov. Regni Veg. 5: 166. 1908. Type. Papua New Guinea. East New Britain: "Vulcanes Kaia" [volcano Kaia], Sep 1905, K. Rechinger & L. Rechinger 4821 (lectotype designated by Symon 1985, p. 129: W [acc. # 0022303]).

Solanum dunalianum Gaudich. var. puberius Bitter, Bot. Jahrb. Syst. 55: 72. 1919. Type. New Guinea. East Sepik: "Kaiser-Wilhelmsland, Hauptlager Malu" [base camp near present-day town of Ambunti], C.L. Ledermann 10718, 12250 (syntypes; type material presumably destroyed at B, see Veldkamp et al. 1988; no duplicates found).

Type.

Indonesia. Malaku: Pisang Island , Moluccas Islands , [Dec 1818], C. Gaudichaud s.n. (lectotype designated by Bean 2004, pg. 672: P [P00369093]; isolectotype: P [P00369092]) .

Description.

Shrub or small tree to 4 m tall, unarmed or sparsely prickly. Stems erect, unarmed or with a few scattered prickles, glabrous or very sparsely stellate-pubescent; prickles to 3.2 mm long, to 3.6 mm at the base, straight, narrowly triangular with the sides concave from a wide base, yellow-ferruginous, glabrous; trichomes porrect-stellate, sessile, the rays 6-8, ca. 0.1 mm long, the midpoints shorter to equal to the rays, white to yellow in dry material; new growth glabrous to sparsely pubescent with mixture of stellate and minute glandular trichomes, brownish to black in dry material; bark of older stems dark brownish red, glabrous. Sympodial units difoliate, the leaves geminate. Leaves simple, not lobed, the blades of major leaves 19.7-30 cm long, 9.5-16 cm wide, ca. 2 times longer than wide, ovate to elliptic, the minor leaves half as large as or the same size as the major leaves, subcoriaceous, slightly discolorous, unarmed or with a few prickles along the midrib; adaxial surface densely pubescent with a mixture of numerous minute glandular trichomes and a few porrect-stellate trichomes, the glandular hairs to ca. 0.04 mm long, the stellate trichomes with 6-8 rays, 0.1-0.2 mm long, the midpoints shorter to equal to the rays; abaxial surface moderately pubescent with similar sessile porrect-stellate and glandular trichomes; major veins 12-16 pairs, drying light brownish yellow; base short to very long attenuate, oblique; margin entire or slightly wavy; apex subacute to acute, or short acuminate; petioles 1.5-9 cm long, 1/9-1/6 of the leaf blade length, unarmed or occasionally armed with a few broad-based prickles to 3.9 mm long, to 2.5 mm in diameter at the base, straight, yellow-ferruginous, glabrous or with a few stellate trichomes like those of the blades. Inflorescence to 2 cm, apparently lateral, forked or several-branched, with ca. 50 flowers, 5-15 flowers open at any one time, glabrous to moderately stellate-pubescent on the youngest parts, with sessile porrect trichomes like those of the stems; peduncle 4-12.6 mm long, unarmed; pedicels 5.1-18.6 mm long, 0.3-0.4 mm in diameter at the base, 0.7-1.1 mm in diameter at the apex, erect, unarmed, glabrous to moderately stellate-pubescent with porrect trichomes like the inflorescence but often with longer rays, articulated at the base. Buds fusiform, exserted from the calyx before anthesis. Flowers 4-5-merous, apparently all perfect. Calyx with the tube 1.4-1.9 mm long, campanulate, the lobes 1-1.5 mm long, 1.5-1.8 mm wide, deltate, apex acuminate, the abaxial surface more or less strongly keeled along the midvein, unarmed and glabrous or sparsely stellate-pubescent abaxially with a few porrect-stellate trichomes like those of the pedicels. Corolla 1.8-2 cm in diameter, lavender to violet, stellate, lobed ca. 4/5 of the way to the base, the lobes 8.2-10.5 mm long, 2.5-2.9 mm wide, oblong, spreading at anthesis, densely stellate-pubescent abaxially on parts exposed in bud. Stamens equal; anthers 3.7-5.7 mm long, 0.8-1.3 mm wide, connivent, tapering, yellow, glabrous, poricidal at the tips, the pores directed distally, not elongating to slits with drying. Ovary conical, with a few stellate trichomes; style 6.5-9.5 mm long, filiform, curved towards the apex, glabrous; stigma capitate or slightly bilobed. Fruit a globose berry, several to many per infructescence, 0.8-1.2 cm in diameter, orange to red when mature, the pericarp thin and shiny, glabrous; fruiting pedicels 10.8-18.2 mm long, 0.7-0.9 mm in diameter at the base, ca. 1.5 mm in diameter at the apex, erect; fruiting calyx lobes slightly expending to 1.7 cm long, covering 1/4 of the berry or reflexed, glabrous. Seeds ca. 40 per berry, 1.7-2.5 mm long, 2.5-2.8 mm wide, flattened-orbicular to flattened-reniform, yellow-tan to yellow-ferruginous, the surface minutely pitted, the testal cells pentagonal to sinuate in outline. Chromosome number: not known.

Distribution

(Fig. 21 ). Solanum dunalianum is found from Sulawesi east through New Guinea and south to the Cape York Peninsula in Queensland, Australia. It has also been collected in Vanuatu and Tonga ( Symon 1985).

Ecology and habitat.

Solanum dunalianum typically occurs in disturbed habitats and has been found in secondary rainforest, along roads, in clearings, along streams, and gardens; from sea level to 1,200 m elevation (on New Guinea).

Common names and uses.

None recorded from the region treated here. Papua New Guinea. Eastern Highlands: gonovise (Kerenga LAE 56923); Tonga. Vava‘u: polo jongo (Soakai 1048).

Preliminary conservation status

( IUCN 2019). Least Concern (LC). EOO (887,043 km2); AOO (100 km2). Solanum dunalianum is at the northeastern edge of its range in tropical Asia, the species is common and widely distributed in New Guinea.

Discussion.

Solanum dunalianum is a species primarily of northern Australia and the island of New Guinea ( McClelland 2012) that only just gets into tropical Asia. It was treated as a member of section Solanum Dunaliana Bitter by McClelland (2012) along with a number of other Pacific species such as S. viridifolium Dunal and S. labyrinthinum D.McClelland (see McClelland et al. 2020). Solanum dunalianum is one of the few species in this group that has been included in molecular analyses (e.g., Aubriot et al. 2016a) and it resolves as part of the 'Sahul-Pacific clade’ and member of a group with S. schefferi (as S. lianoides ) and S. graciliflorum . Within the area treated here, S. dunalianum is distinctive in its branched inflorescence with small red fruits and almost glabrous vegetative parts with very few, if any prickles. Other taxa in the area with several-branched inflorescences are usually densely and variously pubescent (e.g., S. giganteum , S. graciliflorum , S. pseudosaponaceum , S. torvoideum ).

The two collections from northern Papua New Guinea cited in the protologue of S. dunalianum var. puberius were destroyed in Berlin, and we have found no duplicates of these, despite extensive searches. Ledermann’s travels are well-documented ( Ledermann 1919; van Steenis-Kruseman 1985; Veldkamp et al. 1988), and many of the areas he visited have not been accessed since ( Takeuchi and Golman 2002), so we delay neotypifying this name until such collections are available or duplicates of Ledermann’s collections are found.

Specimens examined.

See Suppl. materials 1-3.

Figures

Figure 20. Solanum dunalianum Gaudich. Herbarium specimen collected in Indonesia in 1917 (Kaudern 57, L. 4319974). Photograph credit: Naturalis Biodiversity Center.

Figure 21. Distribution of Solanum dunalianum.