Bucephalandra oblanceolata (M. Hotta) S. Y. Wong & P. C. Boyce

Small obligate rheophytic herbs to 60 cm tall. Stem erect, older plants with stem shortly creeping and with active portion sub-erect, c. 1.5 cm in diam. Leaves many together, erect; petiole 4 - 6 cm long × c. 1.7 mm in diam., weakly longitudinally ridged, adaxially canaliculate, dark reddish brown, sheathing at extreme base, wings extended into a very narrowly triangular ligular portion to 4 cm long; blade narrowly lanceolate to narrowly elliptic, 10 - 14 cm long × 1 - 2 cm wide, coriaceous, semi-glossy dark green adaxially, lighter green abaxially, base sub-cuneate, apex acute to acuminate, apiculate for c. 1.5 mm, margin undulate; midrib abaxially and adaxially somewhat prominent, reddish abaxially; primary lateral and interprimary veins very faint; secondary venation adaxially ± obscure; tertiary venation obscure. Inflorescence solitary; peduncle exceeding petioles, 8 - 10  cm long × c. 1.5 mm in diam., conspicuously longitudinally sulcate and reddish with ridges deeper red. Spathe oblong-ovate, not constricted 3.5 - 4 cm long; lower spathe funnel-form, medium green, persistent; limb inflating at pistillate anthesis, gaping to produce a longitudinal slit to about edge of lower spathe, limb reflexing at staminate anthesis, then somewhat deliquescent along margins, caducous, white, apiculate for c. 2 mm, apiculum brownish; pistillate zone 3 - 4 mm long × c. 1.5 mm in diam., with 3 or 4 spirals of pistils; pistils rhombic-globose, c. 0.5 mm in diam., lime-green; stigma sessile, umbonate, c. ½ diameter of ovary, papillate at anthesis; pistillodes 1 - 3 at base of pistillate zone, squat fusiform, sub-equalling pistils, white; interstice with c. 2 rows of scale-like staminodes, these c. 1.5 mm long × c. 2 mm wide, wedge-shaped, with thicker edge distal, white, initially erect, then spreading, later (post-anthesis) becoming green and persisting to cover developing fruit; staminate zone 3 - 4 mm long × c. 3.5 mm in diam., consisting of 3 or 4 rows of flowers; staminate flowers creamy white; stamen c. 1.3 mm across; filament strap-shaped, short; connective prismatic; thecae inserted ventrally, ellipsoid, c. 1 mm long × c. 0.5 mm wide, smooth; thecae horns very short, c. 0.3 mm long, setaceous, directed outward; appendix bluntly cylindrical, 5 - 7 mm long × 3.5 - 4 mm in diam., cream; appendix staminodes obpyramidal, irregularly polygonal, lower-most c. 1 mm in diam., individually differentiated, with a slight ventral suture, upper staminodes smaller, c. 0.5 mm in diam., often somewhat coalesced, all tops slightly echinate, with larger staminodes also with a raised echinate rim. Fruiting spathe funnel-form, c. 1 cm in diam., with shield-shaped staminodes persistent, turning pale green, spent distal part of spadix falling; Fruit and seed not seen.