What’s a dichotomous key? Help

Agastache

Reference: Lint and Epling (1945).

Choose this species
A. foeniculum
1a. Leaf blades abaxially whitened by dense, minute, white hairs; calyx minutely pubescent; petioles of middle leaves 10–15 (–20) mm long
See list of 2 species in 1b
CHOOSE THIS LEAD
1b. Leaf blades green abaxially, the pubescence (when present) not altering the background color of the blade; calyx glabrous; petioles of middle leaves (15–) 20–50 mm long
- Choose this species
  A. nepetoides
  2a. Calyx lobes 1–1.5 mm long, narrow-ovate; corolla green-yellow; inflorescence 10–15 mm thick; floral bracts broad-ovate and tipped by a short, acuminate point; stems glabrous or minutely pubescent on middle internodes; leaf blades pubescent across the surface abaxially
- Choose this species
  A. scrophulariifolia
  2b. Calyx lobes 2–2.5 mm long, narrow-triangular; corolla purple; inflorescence 15–20 mm thick; floral bracts round-ovate and tipped by an elongate, caudate-acuminate point; stems with some longer hairs on the middle internodes; leaf blades pubescent mainly on the major veins abaxially

Show photos of: Each photo represents one species in this genus.