close up of the flower head

Flowering - May - September.

Habitat - Prairies, glades, wooded bluffs, streambanks, railroads.

Origin - Native to U.S.





Stems - To +1.5m tall, herbaceous, erect, 4-angled, glabrous, multiple from base, simple to branching above, hollow, often forming roots from nodes just above and at ground level, rhizomatous.

Leaves - Opposite, sessile, linear to linear-lanceolate, serrate(teeth with curved apices), acute to acuminate, glabrous, to 15cm long, 1.5cm broad, with prominent midrib.

Inflorescence - Single flowers from axils of small bracts forming a dense elongate spike to +40cm(inĀ  fruit). Axis of inflorescence dense pubescent. Flowers sessile or with a pedicel -1mm long. Subtending bracts sessile, lanceolate, acuminate, to +1cm long, (larger in fruit), dense pubescent.

Flowers - Corolla bilabiate, pinkish, pubescent externally. Corolla tube to +/-2.3cm long, constricted at base where surrounded by calyx, expanded beyond calyx. Upper lip 8-9mm long, 7-8mm broad, truncate to rounded at apex, the sides parallel. Lower lip 3-lobed. Lateral lobes 3-4mm long, 3mm broad. Central lobe 5-6mm long, 4-5mm broad, with purple spotting internally,(purple coloration extended into throat of corolla). Stamens 4, didynamous, ascending under the upper lip of the corolla. Filaments adnate for most of length(seemingly by dense pubescence), white or tinged with pink. Anthers purplish-brown, 1.7mm long. Style inserted between stamens (and slightly longer), white, glabrous, 2.5cm long. Stigma 2-lobed, filiform.Ovary 4-parted, green, glabrous. Calyx tube 6mm long(in flower), dense pubescent, pitted internally, 5-lobed. Lobes equal, acute, 2.2mm long(in flower). Calyx accrescent, to +1cm in fruit. Nutlets to +3mm long.