(L.) Vahl, Enum. Pl.
Berbena, Blue porterweed, Gervao, Jamaica, Verbena, Vervain, Rinchao, Verbena azul, Brazilian tea, Cola de millo
Herb, to ca 1 m tall, sparingly pubescent to glabrate, sometimes slightly woody basally. Petioles absent or to 1 cm long; blades oblong to oval, obtuse to acute at apex, cuneate at base, decurrent onto petiole, to ca 11 cm long and to ca 4.5 cm wide, scaberulous above, glabrous below but with sparse jointed trichomes on primary veins, the margins serrate and ciliate-scabrous. Spikes terminal, to 20 (50) cm long, terete, 3-4 (5) mm wide; flowers at first erect, later embedded in the thickened rachis; bracts subtending pits in which flowers are immersed, acute, to 5 mm long and ca 1-1.5 mm wide, the margins scarious; calyx tubular, ca 5 mm long, shallowly 4-toothed on the side facing away from stem, notched to 1 mm on side next to stem; corolla salverform, shades of blue, violet, and purple, ca 10 mm long, the tube slightly curved, the limb ca 8 mm wide; perfect stamens 2, inserted above middle of corolla tube, included; filaments very short; thecae divergent; staminodia 2, posterior, minute; style ca 6 mm long, filiform; stigma terminal, persistent on fruit after corolla falls. Fruits oblong-linear, emerging from rachis pits at maturity, dry, splitting into cocci, the cocci 2, long, hard, narrow; seeds 1 per coccus, linear. Woodworth & Vestal 739.
Rare. Flowering and fruiting throughout the year. Alabama and Mexico to Ecuador and Brazil; West Indies; introduced into parts of tropical Africa, Asia, Australia, and Oceania. In Panama, known from tropical moist forest in the Canal Zone, Colón, San Blas, Chiriqui, Los Santos, Panama, and Darien, from premontane wet forest in Chiriqui and Panama, and from tropical wet forest in Bocas del Toro and Colón.