Zingiber ultralimitale Ardiyani & A.D. Poulsen subsp. matarombeoense Ardiyani & Ardi, 2021

Ardiyani, Marlina, Ardi, Wisnu H. & Santoso, Wahyudi, 2021, Zingiber ultralimitale subsp. matarombeoense Ardiyani & Ardi (Zingiberaceae), a new subspecies from Sulawesi, Phytotaxa 527 (1), pp. 32-40 : 34-39

Zingiber ultralimitale Ardiyani & A.D. Poulsen subsp. matarombeoense Ardiyani & Ardi , subsp. nov. ( Figs. 3–5 )

Sect. Zingiber

This species can be distinguished from Z. ultralimitale Ardiyani & A.D. Poulsen subsp. ultralimitale in the adnation of labellum (adnate to lateral staminodes in Z. ultralimitale subsp. matarombeoense vs free in Z. ultralimitale subsp. ultralimitale ), the shape of the labellum (ovate with emarginate apex in Z. ultralimitale subsp. matarombeoense vs obovate, deeply bilobed in Z. ultralimitale subsp. ultralimitale ), and the ligule (longer in Z. ultralimitale subsp. matarombeoense 10–18 mm long with emarginate apex vs. 8 mm long, deeply bilobed in Z. ultralimitale subsp. ultralimitale ).

Type:— INDONESIA, South-East Sulawesi Province, North Konawe Regency, Matarombeo mountains , Mataraki , S 3.09870, E 121.96713, 141 m alt., 18.ii.2017, W.Ardi WI 168 (holotype BO ; isotype SING ).

Lithophytic herb. Rhizome branching profusely, 15 mm across, yellowish brown externally, yellowish internally, smell like Zingiber officinale , slightly bitter and hot; roots with elongated tubers to 3.5 × 1 cm, white in cross-section, plain taste. Leafy shoots in a compact clump of up to six pseudostems, 1.5–2 cm between leafy shoots, to 65 cm high, with 13–19 leaves. Leafless shoot light brown. Base of leafy shoot to 1.5 cm diam., yellowish brown. Sheaths light green to mid-green with reddish brown tinge, hairy. Ligule 10–18 mm long, membranous, emarginate up to 1 mm depth, hairy, pale green and getting dried at the margin. Petiole 2–11 mm long, channelled above, hairy abaxially along the length. Lamina ovate to narrowly ovate, 10.5 × 4.5 cm to 15.5 × 3.5 cm, slightly plicate, yellowish green to mid-green, glabrous above, pale green and sparsely hairy beneath especially near midrib, base cuneate to truncate, apex long acuminate. Inflorescence erect, to 13 cm long, arising close to the base of leafy shoot, with 10 flowers, 1–2 flowers open at a time in late morning. Peduncle 3–6 cm long with 5 peduncular bracts, upper one to 4.5 cm long, sparsely hairy. Spike 8 × 2.5 cm. Bracts not laxly arranged, rachis concealed, each subtending a single flower, lowermost bract c. 4.5 × 2 cm, light green towards apex, cream yellow towards the base, with visible cross-veins and hyaline margins, sparsely hairy, apex cucullate, finely ciliate at apex, glabrous inside. Bracteoles shorter than bracts, 3.5 × 1.5 cm (when flattened), split to base, margins almost supervolute, translucent light green, glabrous. Calyx c. 2.0– 2.2 cm long, tubular with one incision in less than upper half, membranous, translucent cream, minutely three-toothed at the apex, pubescent at apex. Corolla tube c. 3.0– 3.5 cm long, pale yellow; dorsal corolla lobe ovate, c.2.0–2.1 × 0.9–1 cm, pale orange-yellow; lateral corolla lobes narrowly ovate, c. 1.9 × 0.5 cm, adnate c. 5 mm to base of labellum, pale orangeyellow. Labellum ovate, c.1.5 × 1 cm, emarginate, incision c. 1 mm, margin curled inward, apex outward, glabrous throughout, pale orange-yellow. Lateral staminodes (side lobes) petaloid, ovate, c. 1 × 0.7 cm, pale orange, joined to labellum. Stamen c. 2.3 cm long, anther sessile, c. 1.3 cm, crest 1 cm long (when stretched), wrapped around style, incurved, pale orange. Anther thecae open along their entire length, ± white. Style pale yellow. Stigma tubular with a downwards-facing, ciliate ostiole, held by anther crest; epigynous glands 2, subulate, 2–4 mm long, cream. Ovary c. 3 × 3 mm, trilocular, with axile placentation, pale yellowish green. Fruit not seen.

Distribution:— Indonesia; endemic to Sulawesi, Southeast Sulawesi, Matarombeo massif.

Etymology:— The subspecies epithet matarombeoense is from the locality Matarombeo where this subspecies is found.

Ecology and habitat: — Growing on the crevice of limestone rocks and also co-occuring with Begonia matarombeoensis D.C. Thomas & Ardi (2018) .

Provisional IUCN conservation status:— Critically Endangered CR B2ab(iii). This subspecies is only known from two collections in the Matarombeo massif, Southeast Sulawesi. The known localities and the forests are not gazetted as protected areas. In combination of the damaging affect of land use (particularly oil palm and nickel mining) on the habitat at Matarombeo periphery with very small EOO and AOO, this warrants a Critically Endangered (Cr) status ( IUCN 2012).

Additional specimens examined:— Indonesia, South-East Sulawesi Province, North Konawe Regency, Matarombeo mountains , Anoa forest , S 3.31742, E 122.07019, 86 m alt., W. Ardi 15.ii.2017, W. Ardi WI 156 ( BO) .

Figures

FIGURE 3. Pollen of Z. ultralimitale subsp. ultralimitale and Z. ultralimitale subsp. matarombeoense (W.H. Ardi WI 168). A. SEM of Z. ultralimitale subsp. matarombeoense made by Yuni Apriyanti.. B. SEM of Z. ultralimitale made by Zhou Pu (permission granted from Zhou Pu and the Garden’s Bulletin Singapore).

FIGURE 4. Zingiber ultralimitale subsp. matarombeoense Ardiyani &Ardi. A. Habit. B. Leafy shoot and inflorescence.C. Sheath, ligule, and petiole. D. Rhizomes and root tubers. E. Flower, front view. F. Flower enclosed by bract, lateral view. G. Bract. H. Bracteole. I. Calyx. J. Corolla lobes. K. Labellum.L. Corolla tube, stamen and stigma.M. Ovary and epigynous glands. N. Ovary, cross section.A from Wisnu Ardi WI 156; B from Wisnu Ardi WI 168 (Photos: W.H. Ardi).

FIGURE 5. Line drawing of Zingiber ultralimitale subsp. matarombeoense Ardiyani &Ardi. A. Leafy shoot and inflorescence. B. Leaves. C. Rhizome, including roots with tubers. D. Flower, front view. E. A single flower with bracteole. F. Sheath, ligule, petiole and base of leaf. G. Ovary, cross section. H. Ovary and epigynous glands. I. Calyx. J. Bracteole. K. Bract. (Drawn by W. Santoso & M. Ardiyani).