Solanum pseudopedunculatum D.McClelland, 2020

McClelland, Donald H. R., Nee, Michael & Knapp, Sandra, 2020, New names and status for Pacific spiny species of Solanum (Solanaceae, subgenus Leptostemonum Bitter; the Leptostemonum Clade), PhytoKeys 145, pp. 1-36 : 1

Solanum pseudopedunculatum D.McClelland sp. nov. Figure 8

Diagnosis.

Like Solanum inamoenum Benth. but differing in the congested inflorescence with the basal flower borne at the very base of the inflorescence and the inflorescence with a pseudo-peduncle, longer pedicels, and larger flowers and fruits.

Type.

Fiji. Vanua Levu: Mathuata, summit ridge of Mt. Numbuiloa, east of Lambasa, 500-590 m, 29 Oct - 6 Nov 1947 (fl, fr), A.C. Smith 6467 (holotype: US [acc. #1966675, barcode 02838867]; isotypes: A, BISH [acc. #181936], K [K000922644], L [L0531787], NY [00828289], P [P00315297], S).

Description.

Shrub or small tree to 4 m, the internodes to 6.5 cm long, unarmed. Stems densely pubescent with yellow, sessile or stalked porrect-stellate trichomes, the stalks to ca. 0.2 mm, the rays 4-8, 0.15-0.2 mm long, the midpoint shorter than the rays; new growth moderately pubescent adaxially with sessile and stalked porrect-stellate trichomes and minute glandular papillae ca. 0.05 mm long; bark reddish brown. Sympodial units difoliate, the leaves geminate, members of a pair more or less equal in size and shape. Leaves simple; blades 6.0-15.0 cm long, 2.0-4.7 cm wide, ca. 2.5-4.2 times as long as wide, ovate to elliptic, chartaceous, concolorous, unarmed; adaxial surfaces glabrescent with scattered stalked porrect-stellate trichomes, the stalks to ca. 0.2 mm long, the rays 4-8, 0.2-0.4 mm long, the midpoint equal to or longer than the rays; abaxially sparsely to moderately pubescent with stalked porrect-stellate trichomes, the stalks to ca. 0.2 mm long, the rays 4-8, 0.25-0.4 mm long, the midpoint equal to or longer than the rays; principal veins 6-8 pairs, the midrib raised abaxially, distinct adaxially, the lateral veins weakly brochidodromous, raised abaxially, distinct adaxially; base cuneate to attentuate, equilateral or oblique; margins entire; apex acuminate, occasionally obtuse; petiole 0.8-2.0 cm long, 0.5-1.0 mm in diameter, moderately stellate-pubescent with trichomes like those of the leaves, channeled above. Inflorescence to ca. 1.3 cm long, appearing lateral, extra-axillary, in the middle 1/3 of the internode, unbranched, with few to 8 flowers, densely pubescent with sessile and stalked porrect-stellate trichomes; peduncle ca. 0.6 cm long, ca. 0.5 mm in diameter, stellate-pubescent like the inflorescence axes; pedicels 0.8-1.4 cm long, 0.4-0.5 mm in diameter at the base, 0.8-1.4 mm in diameter below the calyx, straight, gradually increasing in diameter in the distal 1/4-1/3, moderately to densely pubescent, articulated at the base; pedicel scars evenly spaced 1.0-2.4 mm apart, rigid, in two rows. Buds globose, the calyx moderately stellate-pubescent, the corolla densely stellate-pubescent where exposed in bud, strongly exserted from the calyx before anthesis. Flowers 5-merous, all perfect or apparently so. Calyx 1.0-1.6 mm long, appearing nearly truncate with minute deltate or apiculate lobe tips, the tube 0.4-0.8 mm long, the lobes 0.5-0.8 mm long, not splitting or splitting in the sinuses during fruit development and then the lobes deltate, sparsely to moderately pubescent abaxially, glabrous adaxially. Corolla ca. 1.5 cm in diameter, stellate, white, the interpetalar tissue poorly developed, glabrous, the lobes 3.1-4.2 mm long, 2.2-2.9 mm wide, deltate, spreading at anthesis, glabrous adaxially, moderately stellate-pubescent abaxially. Stamens equal; filament tube minute; free portion of the filaments 0.6-0.9 mm long, glabrous; anthers 1.5-2.1 mm long, 1.0-1.2 mm wide, somewhat tapering, straight, yellow, spreading, poricidal at the tips, the pores directed distally. Ovary ca. 1.2 mm in diameter, globose, with a few stellate hairs and a few minute and simple glandular hairs near the apex; style 3.1-4.0 mm long, 0.3-0.4 mm in diameter, longer than the stamens, exserted beyond the anther cone, filiform, straight, sparsely pubescent in the basal ca. 1/3 with minute glandular hairs; stigma 0.5-0.6 mm in diameter, capitate, minutely papillose. Fruit a globose juicy berry, 0.7-1.0 cm in diameter, variously reported as orange, red becoming black, and purple when mature, glabrous, the pericarp thin, glossy, somewhat translucent; fruiting calyx lobes 0.5-0.9 mm long, 1.5-1.7 mm side, sparsely stellate-pubescent, appressed to the surface of the berry; fruiting pedicels 1.7-2.3 cm long, 0.3-0.6 mm in diameter at the base, 1.1-1.6 mm in diameter below the calyx, straight, gradually increasing in diameter in the distal 1/3-1/2, sparsely stellate-pubescent. Seeds 20-40 per fruit, 1.8-2.0 mm long, 2.3-2.8 mm wide, flattened-orbicular and notched at the point of attachment to flattened-reniform, yellow-tan when dry, the surface with the central area nearly smooth, the margins minutely pitted with the testal cells straight-sided (alveolate). Chromosome number not known.

Distribution and ecology

(Figure 9 ). Solanum pseudopedunculatum is endemic to Fiji on the islands of Kanduvau, Vanua Levu, and Viti Levu; it grows in forest and secondary thickets, from 50 to 1,150 m elevation.

Phenology.

Known to flower and fruit February-March and July-December.

Common names and uses.

Fiji. Moloa (Smith 603); tukitukiyandre (Smith 6467).

Etymology.

The specific epithet is derived from the “pseudo-peduncle” of the inflorescence of this species, where the space between the lowermost flower and the rest gives the appearance of an elongate peduncle.

Preliminary conservation assessment

( IUCN 2019). EOO = 17,482 km2 [VU - Vulnerable]; AOO = 24 km2 [EN -Endangered]. Based on the paucity of recent collections and the fragmented populations (5 locations) on three of the islands of the Fijian archipelago we assess Solanum pseudopedunculatum as VU (B1a,b D2).

Discussion.

In his Flora of Fiji, Smith (1991) included many of the specimens here recognized as S. pseudopedunculatum in his concept of S. inamoenum Benth. The two species are not very similar morphologically, however, with leaf and stem pubescence differing in density ( S. inamoenum pubescence is denser and the trichome rays are somewhat longer than in S. pseudopedunculatum ), inflorescence structure (unbranched in S. pseudopedunculatum and highly branched in S. inamoenum ), flower size (to 1 cm in diameter and homostylous in S. pseudopedunculatum , larger and heterostylous in S. inamoenum ) and habitat preference ( S. pseudopedunculatum is a plant of forests and secondary thickets, while S. inamoenum grows near the coast). Solanum pseudopedunculatum is much more similar to S. ratale but can be distinguished by its taller habit, mature leaves that retain pubescence along the veins and lamina, longer pedicels, and larger corolla, anthers, and berries.

Specimens examined.

Fiji. sin. loc., Dec 1904-Mar 1905 (fr), Goddard s.n. (NSW). Kandavu: Hills above Namalata and Ngaloa Bays, 200-400 m, 13-18 Oct 1933 (fl, fr), Smith 141 (BISH, GH, K, NY, P, S, UC, US). Vanua Levu: Mt. Delaikoro, Macuata, 3050 ft, 21 Aug 1962 (fl, fr), Parham & Koroi 12792 (BISH); Thakaundrove, SW slope of Mt. Mbatini [Batini], 300-700 m, 28-29 Nov 1933 (fl, fr), Smith 603 (GH, K, NY, P, S, UC, US). Viti Levu: Serua district, 500 ft, 14 Jun 1961 (fl, fr), Bola 42 (K); Mba ["Tholo North"], Sovutawambu, near Nandrivatu, 750-800 m, 27 Feb - 4 Mar 1941 (fl, fr), Degener 14594 (A, K, NY, US); Nadarivatu, 2700 ft, 1907 (fl, fr), Gibbs 615 ( BM× 2); Mba (formerly Tholo North), western and southern slopes of Mt. Tomanivi (Mt. Victoria), 850-1150 m, 7 Jul - 18 Sep 1947 (fl, fr), Smith 5273 (A, K, L, NY, P, S, US); Serua, Hills west of Waivunu Creek, between Ngaloa and Korovou, 50-150 m, 23 Nov - 7 Dec 1953 (fl, fr), Smith 9223 (BISH, GH, K, L, NY, P, S, UC, US); Nadarivatu, road to Suva, 27 Nov 1906 (fl, fr), Thurn 294 (K).

Figures

Figure 8. Solanum pseudopedunculatum D. McClelland (holotype Smith 6467, incorrectly labelled as S. nelsonii. US [acc. 1966675, barcode 02838867]). Reproduced with permission.

Figure 9. Distribution of Solanum pseudopedunculatum and S. ratale.