Bucephalandra Schott

Minute to rather large evergreen, obligate (very seldom facultative) rheophytic herbs. Stem creeping and rooting, with active apex upright, or erect, or stems rooted at base with remainder pendent and active tips ascending. Leaves mostly numerous; petiole shorter, equalling, or longer than leaf blade, often with conspicuous longitudinal ridges; petiolar sheath with a long marcescent ligule; blade elliptic, elliptic-oblong, linear-oblanceolate or obovate, stiffly coriaceous to membranous, often punctate abaxially, rarely so adaxially, apex mostly with a tubular mucro; primary lateral veins pinnate, adaxially flush with blade to prominently raised, abaxially ± flush with blade, running into variously distinct marginal vein; interprimary veins parallel-pinnate; higher order venation either parallel-pinnate or reticulate, or tessellate, usually very faint. Inflorescence solitary, or a few in sequence with each separated by a conspicuous prophyll or less often a foliage leaf; peduncle sub-equalling to much-exceeding petiole at anthesis, rarely (Bucephalandra gigantea) much shorter, always elongating later, often longitudinally keeled. Spathe ellipsoid to lanceolate, cuspidate, not constricted; lower spathe broadly funnel-form at and post-anthesis, persistent into fruiting, later subtending and enclosing developing fruits, light green to yellow or reddish, convolute; limb white, pink, or yellow, gaping at pistillate anthesis, variously senescing and then caducous at onset or during staminate anthesis. Spadix sessile or very briefly stipitate, shorter than spathe, usually with a few pistillodes at extreme base; pistillate zone cylindric to obconic, mostly narrower than upper parts, with pistils in 2 - 8 spirals; pistils mainly depressed globose or depressed trapezoidal, 1-locular; ovules many, orthotropous, attenuate toward micropyle, funicle distinct, placenta basal; stigma sessile, discoid, umbonate to slightly concave in centre, narrower than ovary; sterile interstice a few rows (usually 2, sometimes as many as 5 or as few as 1) of flattened, smooth, scale-like motile staminodes, these erect at pistillate anthesis, deflexing prior to staminate anthesis to seal lower spathe, turning green and persisting into fruiting; staminate zone with 2 - 9 rows of stamens; flowers unistaminate; filament usually distinct but very short, flattened, connective either inconspicuous or most often expanded as an extension of filament into a flattened triangular-cordate or spathulate structure with thecae on ventral surface of distal arms; thecae ellipsoid to globose, extrorse, dehiscing by a pore at tip of a short to long conspicuous apical horn; pollen extruded in a droplet, inaperturate, ellipsoid, medium-sized (range 28 - 30 µm long; Grayum 1992: 21), exine psilate. Appendix globose or ellipsoid to (sub-)cylindric, or bullet-shaped, composed of columnar to obpyramidal irregular polygonal to rounded apically papillose, echinate, smooth, or brain-like staminodes, uppermost often ± connate, less often appendix entirely comprised of connate staminodes. Fruit a globose to ellipsoid berry with numerous seeds, protected until maturity by persistent interstice staminodes; seed narrow-ellipsoid, with long, curved micropylar appendage, testa very slightly longitudinally ribbed to scabrous; embryo straight, elongate; endosperm copious.