Boesenbergia truncata N.F.Lam, 2022

Lam, Nyee Fan, Ibrahim, Halijah, Sam, Yen Yen, Mohammad Zakaria, Rozainah & Poulsen, Axel Dalberg, 2022, Two new species of Boesenbergia (Zingiberaceae), from Sabah, Malaysia, PhytoKeys 211, pp. 81-92 : 81

Boesenbergia truncata N.F.Lam sp. nov.

Figs 3 , 4 , 5

Diagnosis.

The new species resembles B. orbiculata by the short petiole (c. 2 cm long) and the bilobed calyx, but differs in having truncate leaf base, an acute leaf apex (vs. sub-obicular, obtuse, or occasionally retuse), paired opposite leaves, and lamina parallel to the ground (vs. a single shoot), anther thecae dehiscing by pore (vs. slit), and the lamina slightly narrow (3.4-3.6 cm vs. 4-7 cm) (Table 1 ).

Type.

Malaysia. Borneo. Sabah. cult. at Kipandi Park, Moyog, 05°54.68'N, 116°06.27'E, 700 m elevation. 12 October 2016, Lam Nyee Fan 342 (holotype BORH!, isotype SAN). Original material collected near the park, by Linus Gokusing (BS-09), 100 m west of Kipandi Park , Sabah, 05°52.28'N, 116°14.95'E, 700 m elevation .

Description.

Terrestrial, evergreen, herb. Rhizome fibrous, subterranean, ca. 2 cm long internodes, base ca. 0.4 cm in diameter, light brown, roots white, ca. 5 cm long. Leafy shoots ca. 11.5 cm tall, with erect pseudostem ca. 1.5 cm long, with 1 sheath, ca. 1.4 × 0.6 cm, glabrous, veins 1 mm apart, green with light purple at base, margins entire. Ligule 0.3 cm long, entire, light brown, glabrous. Petiole 1.4-2 cm long, canaliculate, green, base reddish up to middle. Leafy shoots with two leaves opposite to each other and parallel to the ground. Lamina unequal elliptic, 5.2-6.5 × 3.4-3.6 cm, dark green above, lighter green beneath, glabrous, margin entire; base truncated, apex acute with acumen ca. 1 mm. Inflorescence ca. 2.5 × 1.5 cm, peduncle ca. 0.45 cm, flowers arranged in one-sided spiral, 8 flowers including one new bud and 1 old bud, one flower open at a time. Fertile bracts narrowly lanceolate, ca. 1.8 × 3 cm, white, outer and inner surfaces pubescent, margin entire, apex caudate. Bracteoles linear elliptic, ca. 1.5 × 2 cm, white, outer and inner surfaces pubescent, margin entire, apex acuminate. Flower white, born singly from each bract and bracteole, calyx 0.4 cm long, tubular, white, pubescent, corolla tube-white, pubescent, apex acute, dorsal lobe lanceolate, ca. 0.8 × 0.2 cm, concave, lateral lobes elliptic, ca. 0.6 × 0.2 cm, labellum obovate, ca. 0.6 cm × 0.5 cm, yellow band at base in the centre until the apex, curved-backward, lateral staminodes oblong, ca. 0.3 × 0.1 cm, white, tip rounded, pubescent, stamen ca. 2.3 cm long; filament ca. 4 × 1 mm (widest at base), glabrous adaxially and abaxially, anther ca. 2 mm long, glabrous; anther crest bilobed, glabrous; thecae oblong, ca. 0.2 × 0.1 cm, white, pubescent, dehiscing by pore, stigma emarginate, white, glabrous. Fruit not seen.

Distribution.

Endemic in Borneo, Sabah; known only from Kipandi Park of Crocker Range.

Etymology.

The species epithet refers to truncated leaf base.

Ecology.

Primary forest, hill slope at 500-800 m elevation.

Conservation status.

Vulnerable (VU D2). The taxon was assessed using criteria described in IUCN (2001). The taxon is endemic to Sabah and only found at Crocker Range, Sabah, Malaysia. There were only 3 populations found at the site of collection. This taxon is not found outside the type locality.

Figures

Figure 3. Boesenbergia truncata A habit B rhizome and roots C spike with one open flower D flower E ract, bracteole, calyx, corolla lobes, staminodes, labellum, floral tube with stamen F stamen, ventral view (Photographed by Lam Nyee Fan).

Figure 4. Boesenbergia truncata Lam N. F., sp. nov. A habit, lateral view B bract C bracteole D calyx E flower F spike with one open flower G stamen, ventral view (Drawing by Lam Nyee Fan). Scale bars: 1 cm (A, B); 5 mm (C); 1 cm (D); 1 mm (E).

Figure 5. Shape of base of leaf of Boesenbergia truncata.