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

Small, rather robust obligate rheophytic herbs to c. 17 cm tall, occurring mainly as individual plants, only occasionally in small patches. Stem creeping, branching repeatedly, branches 0.5 - 6  cm long × 2 - 4 mm in diam., rooting with active portions bright reddish purple, sub-erect. Leaves arching, to c. 10 together; petiole c. 4 cm long × c. 2 mm in diam., adaxially strongly canaliculate, deep reddish, sheathing at extreme base, wings extended into a very narrowly triangular ligular portion to 1 cm long; blade elliptic, 8 - 10 cm long × 2 - 2.5 cm wide, coriaceous, semi-glossy dark green adaxially, tinged reddish pink abaxially, base cuneate, apex rounded and apiculate for c. 1.5 mm, margin somewhat undulate; midrib adaxially prominent, abaxially prominent and reddish; primary lateral veins 3 or 4 on each side, diverging at 25° - 60° and running to a marginal vein; interprimary veins alternating with primaries, almost of equal width; secondary venation adaxially ± obscure. Inflorescence solitary; peduncle sub-equalling to somewhat exceeding petioles, 3 - 5 cm long, conspicuously longitudinally sulcate and distally winged, bright reddish purple, this colour derived from multitudinous, minute speckles. Spathe broadly ovate, not constricted, c. 2.5 cm long; lower spathe funnel-form, pale green, persistent; limb inflating and gaping distally at pistillate anthesis, caducous during late staminate anthesis, glistening white, apiculate for c. 3 mm, apiculum pale green. Spadix 1 - 1.5 cm long, very shortly stipitate; stipe less than 0.5 mm long, longitudinally sulcate, glossy white; pistillate zone 2.5 - 3 mm long × c. 2 mm in diam., with c. 3 spirals of pistils; pistils cylindric-globose, c. 0.5 mm in diam., pale lime-green; stigma sessile, umbonate, c. 3/4 diameter of ovary, papillate at anthesis, later (post-anthesis) sunken centrally; pistillodes in a single incomplete row at base of pistillate zone, squat fusiform with a terminal beak, in all c. 0.35 mm in diam., c. ½ as wide, glossy white; interstice with 1 - 3 rows of scale-like staminodes, these 1 - 2 mm long × 0.8 - 1.5 mm wide, margin slightly thickened, staminodes initially erect (pistillate anthesis), then during staminate anthesis reflexing until perpendicular with spadix axis, with tips somewhat ascending, initially greenish white, later (post-anthesis) becoming green and persisting to cover developing fruit; staminate zone c. 5 mm long × 2 - 3 mm in diam., consisting of 4 or 5 rows of flowers; staminate flowers pale to medium yellow; stamen comparatively large, c. 1 mm across, cream; filament short but conspicuous; connective strap-shaped; thecae inserted lateral-ventrally on connective, individually ellipsoid, c. 1 mm long × c. 0.4 mm wide, smooth; thecae horns c.  ½ length of associated theca, stiffly setaceous, with bases somewhat swollen, spreading to slightly downward-directed during pistillate anthesis, upward-pointing during staminate anthesis; appendix ± globose, c. 4 mm long × c. 3 mm in diam., dark cream to medium yellow; appendix staminodes mostly obpyramidal (although lowermost ones transitioning in appearance to staminate flowers), densely arranged, 0.5 - 1 mm in diam., tops strongly echinate. Fruiting spathe funnel-form, c. 1 cm in diam., medium green, with green shield-shaped staminodes persistent and spent distal part of spadix falling; berry depressed globose, 1 - 1.8 mm long × 1 - 1.5 mm in diam., medium green, with numerous seeds, berries forming a hemispherical cluster protected by persistent staminodes, later pushed off and falling to reveal mature fruits; fruits decomposing at maturity, forming a pulp with seeds held in persistent lower spathe; seeds narrowly ellipsoid, 1 - 2 mm long × 0.25 - 0.3 mm in diam., light brown, very slightly longitudinally ribbed, with a curved micropylar appendage to 1 mm long.