Small to medium-sized evergreen herbs. Mucigel on root cap, adventitious shoots arising from the root. Stem erect or decumbent, usually more or less condensed. Leaves several; petiole sheath short with long, marcescent triangular ligule; lamina elongate-lanceolate to elliptic or oblonceolate, coriaceous, basally cuneate, apex with tubular mucro; primary lateral veins pinnate, running into distinct marginal vein, secondary laterals and higher order venation parallel-pinnate. Inflorescence solitary per module, emerging orthotropic, maturing campylotropic to anatropic during the onset of anthesis; peduncle subequal to or longer than petiole. Spathe stoutly ellipsoid, not constricted, persistent, pink, gaping at anthesis, apex cuspidate to acuminate. Spadix sessile with ± oblique insertion to shortly stipitate with the stipe adnate to the spathe, sometimes with a robust basal sterile zone (pistillodes) or absent; female flower zone cylindric; pistils free, ovary 1-locular, ovules many, placentae 2-4, basal; stigma ± sessile or elevated on a short style, usually as broad as ovary and more or less contiguous with adjacent ones; male flower zone contiguous with female flower zone, cylindric to ellipsoid, equal in thickness to female zone, obtuse; stamens crowded, minutely hairy to papillate, anthers truncate, connective ± flat; thecae oblong-ellipsoid, dehiscing by apical pore; pollen inaperturate, ellipsoid; appendix absent. Infructescence a cluster of free berries held within the persistent, finally disintegrating spathe; berry obovoid to subcylindric, small, green; seed elongate-ellipsoid to cylindric, with long, curved micropylar appendage, testa slightly costate, embryo elongate, endosperm copious.
Ooia is unique in the tribe as so far observed by the persistence of the entire spadix axis through to fruit maturation and dispersal, with the entire axis remaining fresh, and the non-female flowers sloughing away; indeed this is unique in the family. The spathe of Ooia is persistent late into fruit development, at which point the extreme top margin and associated rostrum are shed, enlarging the spathe orifice to allow spent flowers to be shed from the persistent spadix and later to enable the mature fruits, which decompose at full ripeness, to be washed from the spathe via water turbulence. Such inflorescences are pendent and often with their tips submerged in water.