Mentha spicata L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Rhizomatous perennial, 3–10 dm, glabrous or subglabrous (often glandular), the lvs often hirsute along the main veins beneath; lvs sessile or subsessile, lance-ovate or elliptic, 3–7 × 0.8–2.5 cm, 2–3.5 times as long as wide, serrate, ± acute; fls crowded into slender terminal spikes (sometimes interrupted below) 3–12 cm long and 0.5–1 cm thick at anthesis; cal 1–3 mm, the lobes generally hispid-ciliate, the tube without hairs; cor 2–4 mm; 2n=48. Banks of streams and ditches, and other moist places; native of Europe, now widely established in N. Amer. and throughout our range.