HABIT : clump- and colony-forming evergreen herbs, stoloniferous, stem thick, aculeate or unarmed (L. concinna), erect to decumbent, green, epigeal or submersed, internodes relatively long or short. LEAVES : several. PETIOLE : long, aculeate, weakly geniculate apically, sheath relatively short. BLADE : sagittate to hastate-sagittate when juvenile, adult blade deeply pinnatifid in anterior division, posterior divisions pedatifid, sometimes simple, adult blade rarely entire, or bipinnatifid (L. concinna), major veins aculeate on lower surface; primary lateral veins pinnate in anterior division, pedate in posterior divisions, primary lateral veins of each pinna forming submarginal collective vein in pinnatifid leaves, or running into marginal vein in simple leaves, higher order venation reticulate. INFLORESCENCE : solitary. PEDUNCLE : subequal to petiole, aculeate as petiole. SPATHE : linear, very long and narrow (L. spinosa) or broader (L. concinna), very thick and spongy, spirally twisted, marcescent or deciduous, basal part enclosing spadix, gaping at anthesis. SPADIX : shortly cylindric, obtuse, sessile. FLOWERS : bisexual, perigoniate; tepals usually 4, more rarely 6, fornicate. STAMENS : 4(-6), filaments free, broad, connective slender, thecae ellipsoid, dehiscing by longitudinal slit. POLLEN : monosulcate, ellipsoid, medium-sized (mean 27 µm.), exine reticulate, psilate along aperture margins. GYNOECIUM : ovoid to ellipsoid, ovary 1-locular, ovule 1, anatropous, funicle very short, placenta apical, stylar region well developed, shortly attenuate to cylindric, stigma discoid-hemispheric. BERRY : borne in cylindric infructescence, crowded, quadrangular, apically densely muricate to spinose or smooth, 1-seeded, green. SEED : large, compressed-obovoid, testa thin, brown, hard, somewhat rugose, embryo large, somewhat curved, endosperm present but only as a single cell layer.
Clump-forming, evergreen helophytes; stem prickly, aerial, and scrambling to prostrate, internodes distinct, green; petiole prickly, weakly geniculate at apex; leaf blade usually pinnatifid, rarely sagittate or bipinnatifid, fine venation reticulate; spathe spirally twisted, erect, thickened, spongy, marcescent to deciduous; flowers bisexual, perigoniate, tepals free; berries shortly spiny to smooth at apex.