Solanum gibbsiae J.S.Drumm.

Solanum gibbsiae J.S.Drumm. View in CoL

in L.S. Gibbs, Fl. Arfak Mts: 177. 1917.

Type: INDONESIA, Papua Barat province, Arfak mts., Angi lakes, edge of forest by female lake (now lake Anggi Gida ), 7,000 ft, Gibbs 5974 (holo BM [ BM000886173 digital image!]) . Fig. 4 View Fig

Slender shrubs, to 1.5 m high. Stems cylindric when young, prickly; prickles acicular, up to 1 cm long, prickles also on leaves, especially along main veins; bark black or chestnut; densely pubescent with short-stalked stellate trichomes, 4–5 mm across, the rays 8–10, acicular, 1–2.5 mm long. Leaves unpaired, simple to deeply pinnatifid, lobes 2–6 on each side with rounded sinuses, elliptic in overall shape, 3.1–12 × 1.2–4 cm, base truncate to broadly cuneate, margin coarsely repand-dentate, the apex of lobes rounded to acute, leaf apex acuminate or acute, hairs similar to stem, upper surfaces along veins only, lower surfaces furfuraceous with stellate hairs across lamina; petiole 5–10 mm long, mostly armed. Inflorescences simple extra-axillary cymes, 1–3–flowered, peduncle 1–2 cm long, covered with hairs similar to stem, rachis up to 2 cm long, densely to sparsely covered with hairs similar to stem, flowering pedicels 5–7 mm long, covered with stellate hairs similar to stem. Calyx campanulate, c. 2 mm long, lobes minute or teeth-like, acumen c. 0.5 mm long, surfaces covered with hairs similar to stem, especially at the base. Corolla rotate or nearly so, white to rose-purple, midrib purple inside, lobes 5, ovate-lanceolate, 3.25–3.5 × 0.8 mm, apex gradually acuminate, covered with hairs on the outside except at the base, hairs similar to those on stem, smaller; stamens sub-connivent, anthers 2- celled, c. 2.2 mm long, pores apical, glabrous, style exceeding the stamens by c. 0.7 mm, stigma subcapitate. Fruiting pedicels up to 2 cm long, gradually thicker towards distal end. Fruit a globose or depressed globose fleshy berry, red at maturity, 7.5– 10 mm in diameter, 1–3 per infructescence; calyx enlarged in fruit. Seeds c. 12 per fruit, yellowish, subreniform, c. 3 × 2.25 mm, planoconvex.

Flowering & fruiting: Flowering in April and December; fruiting in December.

Habitat: The plants are growing in riverine montane forests, along forest margins in shaded localities at 1900 m elevation. The population from lake Angi Gigi (now Anggi Gigi) was made in valley forests near a small stream.

Distribution: The plant is known only from the Arfak Mountains of the Birds Head peninsula in New Guinea ( Fig. 2 View Fig ). Only two populations are known, one from the female lake Angi (now lake Anggi Gida) and another from north of the male lake Angi (now lake Anggi Gigi).

Specimen examined: INDONESIA, Papua Barat province, Pegunungan Arfak Regency , Anggi district, Irbos , 1900 m, 15.04.2016, Mustaqim 1891 ( BO) .

Conservation status: With the uncertainty of the precise location of the type specimen collection, it is quite hard to assess the current condition of the forests. Fieldtrips made in 2016 and 2018 showed some forest conversion surrounding the location, especially in the lake Anggi Gida, with a decrease in the amount and quality of forests for the species. Forests surrounding lake Anggi Gigi are in better condition and remain relatively undisturbed. The AOO of 8 km 2 falls within CR under criterion B2 (<10 km 2), and the fragmented occurrence of the species and threat from land conversion merits this status. A provisional status of CR, B2ab(iii), is thus proposed ( IUCN, 2012, 2019).

Notes: Solanum gibbsiae can be recognized by its dense indumentum of stellate trichomes across the lower leaf surfaces, straight prickles densely covering the stems, narrowly elliptic or sub-ovate solitary leaves up to 12 × 4 cm in size, and internodal inflorescences. In New Guinea, a species similar to S. gibbsiae is S. rivicola Symon , but the latter differs in having the curved or hooked stem prickles.

Solanum gibbsiae View in CoL was described in 1917 by Drummond (1917) as part of a pioneering book on the flora of the Arfak Mountains by Gibbs (1917) with incomplete morphological detail. Symon (1985) cited the description by Drummond (1917) where the corolla was detailed to be rose-purple in colour differing from the individuals found during the recent botanical trip which had white corollas, but colour variation is relatively common in some Solanum species ( Ugent, 1967; Knapp, 2013). The colour of the berry documented here supports Symon’s (1985) original hypothesis that berries are likely to be red at maturity.