Laticifers absent in foliage leaves but present in stem, roots and cataphylls (Sivadasan, pers. comm.). HABIT : small to medium-sized evergreen herbs, rhizome creeping, thick, rarely stoloniferous (L. nairii). LEAVES : several, cataphylls conspicuous. PETIOLE : sheath fairly long. BLADE : ptyxis involute, ovate, lanceolate, elliptic to almost linear, usually glabrous (hairy in L. nairii), coriaceous; primary lateral veins pinnate, weakly differentiated, running into inconspicuous marginal vein, secondary laterals parallel to primaries, higher order venation transverse-reticulate. INFLORESCENCE : solitary. PEDUNCLE : short, rarely long (L. bogneri), erect at anthesis, deflexed in fruit. SPATHE : marcescent, very thick-walled, outer surface green to purple, completely smooth or very warty on blade, margins basally connate into cylindric or ellipsoid tube (“kettle”), tube sometimes narrowing apically within (by thickening of walls, thus not apparent from outside), inner surface of lower region usually longitudinally furrowed, mouth of tube occluded by transverse, centrally perforated septum with separate transverse flap situated immediately below septum and partly or completely covering male zone of spadix, blade straight or twisted, opening only slightly by narrow longitudinal or spiral slit, or widely gaping, apex acute to long-caudate, inside smooth, uniformly warty or with warts in transverse bands, or covered with shortly branched processes, distinct “collar” around mouth of kettle present or absent. SPADIX : axis slender, female zone usually with 3-5(-7) spirals of gynoecia, rarely in pseudowhorl (L. nairii) or true whorl (L. gomezii), separated from male zone by slender naked axis, male zone cylindric to ellipsoid, terminal appendix small, conoid, apically adnate to spathe behind spathe flap; olfactory bodies present or absent above female flowers. FLOWERS : unisexual, perigone absent. MALE FLOWER : 1(-2)-androus, anthers sessile or with short thick filament, apex somewhat excavated with prominent thickened margin, connective inconspicuous, thecae opposite, each narrowed into an erect horn usually exceeding, rarely equalling thickened margin and dehiscing by apical pore. POLLEN : inaperturate, ellipsoid to ellipsoid-oblong, medium-sized (mean 36 µm., range 35-38 µm.), exine perfectly psilate. FEMALE FLOWER : gynoecium free, broadly ellipsoid to globose, ovary 1-locular, ovules 1-12(-15), orthotropous, tapering towards micropyle, funicle short, bearing very long trichomes, placenta basal, stylar region thick, usually short, rarely long, stylar region and upper part of ovary often conspicuously warty, stigma discoid to hemispheric, sometimes oblique, relatively broad. FRUIT : ± capsular, free, obovoid to prismatic-ellipsoid, often apically warty, rarely smooth, at maturity pericarp splitting and revolute basally to release seeds, infructescence usually globose, deflexed, prostrate. SEED : ellipsoid to narrowly ellipsoid or subcylindric, testa longitudinally costate, dark brown, embryo elongate, endosperm copious.
Helophytes, rarely rheophytes, with thick creeping rhizome; leaf blade simple, ovate to almost linear, fine venation transverse-reticulate; spathe tube with connate margins; spadix entirely enclosed in spathe tube; flowers unisexual, perigone absent. Differs from Cryptocoryne in having female flowers spirally arranged (pseudo-whorl in Lagenandra nairii, whorled in Lagenandra gomezii ) and free; spathe tube "kettle" with connate margins (containing spadix) occupying entire spathe tube; spathe blade usually opening only slightly by a straight or twisted slit; berries free, opening from base; leaf ptyxis involute.