Bucephalandra ultramafica S. Y. Wong & P. C. Boyce

Small obligate rheophytic herbs to c. 16 cm tall, occurring as individuals or small clumps. Stem creeping with active portion semi-erect, c. 1.5 cm in diam. Leaves several together, erect to spreading; petiole 2 - 4 cm long × c. 2 mm in diam., adaxially canaliculate, strongly longitudinally ridged, deep red, sheathing at extreme base, wings extended into a very narrowly triangular ligular portion to 2.4 cm long; blade oblanceolate to narrowly elliptic, 8 - 12 cm long × 1 - 1.5 cm wide, rather thickly coriaceous, semi-glossy very dark green adaxially, pale olive-green with very numerous minute purple glands abaxially, base cuneate, apex acute and apiculate for c. 1.5 mm, margin slightly recurved, midrib abaxially and adaxially very prominent, reddish abaxially; primary lateral veins c. 5 on each side, diverging at c. 45° and running to a marginal vein; interprimary veins ± invisible; secondary venation ± obscure. Inflorescence solitary; peduncle exceeding petioles, 4 - 6 cm long, very conspicuously longitudinally sulcate, distal-most part with scattered minute verrucae, deep red. Spathe broadly ovate, not constricted, 2 - 3 cm long; lower spathe funnel-form, green with many red speckles and red lines that are extensions of pe duncle ridges, persistent; limb inflating at anthesis, gaping distally at pistillate anthesis to create a slit-like aperture, then reflexing at staminate anthesis, finally caducous, externally white with plentiful minute red speckles and a red median line, internally white, apiculate for c. 2 mm, apiculum reddish brown. Spadix 2 - 2.5 cm long; pistillate zone 3 - 4 mm long × c. 2.5 mm in diam., with c. 3 spirals of pistils; pistils rhombic to compressed globose, c.  0.5  mm in diam., lime-green; stigma sessile, umbonate, c. ½ diameter of ovary, papillate and secreting a conspicuous stigmatic droplet at pistillate anthesis; pistillodes 2 - 5 at base of pistillate zone, clavate, c. 0.25 mm tall, glossy white; interstice with 3 rows of scale-like staminodes, these c. 1.8 mm long × c. 2 mm wide, glossy white; staminate zone 4 - 5 mm long × 5 - 6 mm in diam., consisting of 3 or 4 rows of flowers; staminate flowers white; stamen c. 1.5 mm across; filament short, block-like; connective tongue-shaped; thecae inserted ventrally, ellipsoid, c. 1 mm long × c. 0.5 mm wide, smooth; thecae horns c. 1/3 length of associated theca, setaceous, upward-pointing; appendix conoid to bullet-shaped, 5 - 8 mm long × 5 - 7 mm in diam., cream; appendix staminodes columnar, tops polygonal with very rounded angles, somewhat umbonate with a small central depression, c. 0.5 - 1 mm in diam., cream. Fruiting spathe funnel-form, c. 1 cm in diam., yellow-green on a red peduncle, with shield-shaped staminodes persistent, turning yellow green, and spent distal part of spadix falling; fruits and seeds not seen.