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Genus :


Family :



Herbs, subshurbs or shrubs. Leaves sessile, subsessile or petiolate, lamina elliptic-lanceolate to broadly ovate. Inflorescence in terminal raceme with whorls of 6 or less flowers. Bracts reflexed, rarely coloured. Calyx 5-toothed, upper tooth broad, ovate, recurved, margin decurrent on tube, 4 lower teeth subulate or awned, slightly connate or not. Calyx tube ovoid, campanulate, deflexed in fruits. Corolla 2-lipped, upper lip 3 to 4-fid, lower entire, concave, tube longer than calyx, straight or incurved. Stamens 4, declinate, filaments free, without any basal appendage, anther cells confluent. Disk gibbous. Styles slender, entire or slightly notched stigma. Nutlets 4, dry, ovoid or orbicular, smooth, basal scar small.

Key to the species

Serial Key Reference
1a. Stamens exerted O. aristatus
1b. Stamens included 2
2a. Leaves petiolate O. incurvus
2b. Leaves sessile or subsessile O. rubicandus