Pleuranthodium sagittatum Lofthus & A.D.Poulsen, 2020

3. Pleuranthodium sagittatum Lofthus & A.D.Poulsen View in CoL , sp. nov. — Fig. 1b View Fig , 5 View Fig

Similar to P. piundaundense in its yellow-orange flowers but differs by the shorter leafy shoots ( 1.6–1.8 m vs 3–4.1 m), the calyx being pale red and distinctly wrinkled (vs. pale yellow-green and smooth) and entire apex of the labellum (vs bilobed with a 3 mm incision). — Type: A.D. Poulsen, T. Jimbo, W. Banda & T. Muanda 3017 (holo LAE; iso E), Papua New Guinea, Chimbu Province,slopes of Mt Wilhelm , S5°48'52" E145°4'57", 2875 m, 18 Apr.2016, flowering and fruiting GoogleMaps .

Etymology. The epithet is derived from the Latin sagitta, which means arrow and refers to the vernacular name anger keneh yaundo that indicates the resemblance between the spike and an arrowhead.

Terrestrial herb in clump. Rhizome fleshy, short-creeping. Leafy shoot 1.6–1.8 m long, with up to 24 leaves; bases to 6 cm apart, distinctly swollen, c. 2.5 cm across, yellow-green, brownish pubescent; sheath scabrid, yellow-green, lower sheath dead and pale brown, glabrous except pubescent below ligule; ligule shallowly bilobed, 2–3 mm long, reddish brown, pubescent including margin; petiole to 4 mm long, pale green, glabrous; lamina narrowly ovate, to 30 by 7 cm, mid-green, pale green beneath, glabrous, base ± cordate, margin pilose, apex acuminate. Inflorescence subterminal by c. 8 cm, to 15 cm long; free part of peduncle pendulous, round in cross-section, 4–8 cm long, pale yellow-green, minutely tomentose; peduncular bracts 3, cucullate, enclosing the young inflorescence, decreasing in size towards inflorescence, most distant bract to 14 cm long with small, laminoid appendage apically, proximate bracts short and caducous, all bracts red when young turning dark brown when old, glabrous; spike obpyriform, c. 9 by 7 cm composed of a 7–8 cm long rachis with numerous flowers, flowering starting from base. Flower 3–3.4 cm long, not resupinate; pedicel subsessile, pale red, minutely pubescent; calyx 11–13 mm long, distinctly wrinkled, membranous, pale red, glabrous, apex bilobed, ir- regular, semi-operculate, partly ruptured by the emergence of the corolla, without appendages; floral tube 14 mm long, pale orange, sparsely minutely pubescent outside, puberulent inside; corolla lobes pale orange, minutely pubescent along margin, increasingly so towards apex; dorsal lobe c. 8 by 5 mm, oblong elliptic, boat-shaped, acute and cucullate at apex, 3–5-nerved, ± as long as anther (± 0.5 mm), 1–2 mm longer than labellum; lateral lobes 9–5 by c. 6 mm, reaching c. 1 mm longer than labellum, triangular, acute, attached at an angle of c. 45°; labellum cup-shaped, c. 4 mm long, apex of central lobe entire, pale orange, margin sinuate, glabrous; stamen c. 7 mm long, pale orange; filament broadly canaliculate, broadest at base, c. 2 by 3 mm, pale orange, glabrous; anther broadly elliptic, c. 5 by 3.2 mm, apex emarginate (incision c. 0.8 mm deep); thecae dehiscing along their entire length, cream, glabrous; ovary ellipsoid, c. 4 by 3 mm, pale red, very sparsely puberulous; epigynous gland enclosing style from one side, truncate, irregularly lobed, verrucose, c. 1 by 2 mm; style c. 2.4 cm long, cream, glabrous; stigma sigmoid, glabrous, 1 by 0.8 by 0.5 mm, pointing downwards, apex with a transverse, reniform ostiole, glabrous, c. 0.3 mm wide. Infructescence pendulous, free part of peduncle to 8 cm long; peduncular bracts caducous; fruit head cylindrical, to 10 by 4.5 cm; pedicel extending to 0.7 cm long, capsule ellipsoid, slightly trigonous, fleshy, c. 2 by 0.9 cm, orange, glabrous, splitting lengthwise from apex in 3 parts; seeds 3–5 per locule, irregularly folded to ruminate, 5–6 by c. 4 mm, green with small, pinkish red aril.

Distribution — Only known from type collection at Mt Wilhelm, Chimbu province, Papua New Guinea.

Habitat & Ecology — The species has been recorded from an open gap in a montane forest at 2875 m. It was flowering and fruiting in mid-April.

Ethnobotany — During the collecting of the type of this species the local guide, William Banda, gave the information that this species is called anger keneh yaundo in the Kuman language. This vernacular name is also used for P. piundaundense (see above), which has a similar pointed spike and the leafy shoots are similarly used for the construction of bush hut walls.

Conservation status — Although this species has only been collected once, there are no obvious threats. Several popula- tions were encountered during the survey and it seems stable. Even though the montane forest at Mt Wilhelm is not under any formal protection, there are as yet no large-scale logging activities taking place. Use by the local people does not pose a threat to the individuals that would resprout after some leaves had been removed. Thus, the current assessment is that this species is of Least Concern (LC) according to IUCN (2019).