PLANTS: In AZ, annual herbs. LEAVES: opposite with interpetiolar stipules. INFLORESCENCE: cymose or solitary. FLOWERS: heterostylous (distylous) or homostylous; calyces 4-lobed; corollas 4-lobed, funnelform or tubular; stamens 4; stigmas bifid. FRUITS: biloculate capsules, 3/4-9/10 inferior. SEEDS: few-many per capsule, non-crateriform (lacking ventral cavity or depression), the hilum punctiform, or in H. vegrandis crateriform with hilar ridge (latter species atypical for (Hedyotis). NOTES: Ca. 150 spp.; Asia, Australia, Americas. Extremely variable genus with uncertain circumscription. (Greek: hedys = sweet + otos = ear, significance unknown). REFERENCES: Terrell, Edward E. 1995 Rubiaceae. Hedyotis. J. Ariz. - Nev. Acad. Sci. 29(l): 29.
Fls 4-merous; sep lance-linear to ovate; cor salverform or funnelform to subrotate; stigmas 2; capsule partly to wholly inferior, with several to many seeds in each of the 2 locules, loculicidally dehiscent across the top; mostly herbs with small, opposite lvs and rather small to minute fls. (Houstonia, Oldenlandia) 300, cosmop., especially in warm regions. Spp. 1-4 apparently hybridize.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.