1. Agastache nepetoides (L.) Kuntze (yellow giant hyssop)

Pl. 432 c–e; Map 1934

Stems 80–150(–250) cm long, glabrous or more commonly with an inconspicuous band of short, mostly unicellular hairs at the nodes, occasionally sparsely hairy between nodes toward the tip. Petioles 0.8–7.0 cm long. Leaf blades 2–15 cm long, the upper surface glabrous or sparsely short-hairy along the main veins near the base, the undersurface moderately to densely pubescent with short, spreading hairs, more densely so along the veins. Inflorescences 4–20 cm long, 2.0–2.5 cm in diameter, the bracts elliptic-ovate to broadly ovate, shorter than to slightly longer than the calyces. Calyces 4.5–6.5 mm long, pale green to yellowish green, the lobes 2.0–2.5 long at flowering (to 3.2 mm at fruiting), narrowly triangular, tapered to sharply pointed tips. Corollas 5.5–8.0 mm long, greenish yellow to light yellow. 2n=18. July–September.

Scattered nearly throughout the state (eastern U.S. west to South Dakota and Oklahoma; Canada). Bottomland forests, edges and openings of mesic upland forests, banks of streams and rivers, margins of lakes, and bases of bluffs; also pastures, roadsides, and moist disturbed areas.