General:
Perennial herb from a creeping rhizome; stems erect, branched, 30-100 cm tall, glabrous, 4-angled; pungent (spearmint) smell.

Leaves:
Opposite, egg-shaped to lanceolate, 2-7 cm long, 1-2.5 cm wide, toothed, tips pointed, bases rounded, glabrous but often hairy along the main veins beneath, margins toothed; unstalked or nearly so, stalks less than 3 mm long.

Flowers:
Inflorescence of flower clusters crowded into terminal spikes 3-12 cm long and 0.5-1 cm wide (sometimes interrupted below) subtended by linear-lanceolate bracts; corollas tubular, 2-4 mm long, pale lavender to sometimes white, glabrous, 4-lobed, the lobes nearly equal; calyces 1.5-2 mm long, glabrous but often glandular, teeth margins usually stiff-hairy.

Fruits:
Nutlets, 4 clustered together, egg-shaped.

Source:  The Illustrated Flora of British Columbia

If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.

Illustration Source:  The Illustrated Flora of British Columbia

Synonyms and Alternate Names:
Mentha cordifolia auct.
Mentha longifolia var. mollissima (Borkh.) Rouy
Mentha longifolia var. undulata (Willd.) Fiori
Mentha spicata var. longifolia L.
Mentha spicata var. spicata L. [superfluous autonym]
Mentha sylvestris L.
Mentha viridis L.