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See list of 2 species in this genus

Leaf blade measurements in the following key are for those leaves produced along the main axis of the stem. Leaves from within the branches of the capitulescence (i.e., bracts), which are frequently (and incorrectly) referenced for measurements, will yield smaller results. Reference: Haines (2006).

  • 1a. Leaf blades with numerous and prominent resin glands [Fig. 409], 1–3 (–6) mm wide; plants ± glabrous on the stem and leaf surfaces; axillary fascicles often well developed and conspicuous throughout much of the stem
  • 1b. Leaf blades with few and/or inconspicuous resin glands, usually 3–12 mm wide; plants varying from glabrous to conspicuously pubescent on the stem and abaxial leaf surfaces; axillary fascicles, if present, usually poorly developed and sparse

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