Bouteloua

1. Inflorescences with 20–40 (–55) spikes; spikes detaching from the rachis at maturity.

B. curtipendula

1. Inflorescences with 1–4 spikes; spikes persisting on the rachis.

2. Spikes 15–40 mm long, with ca. 17–50 spikelets; plants in small clumps.

B. gracilis

2. Spikes 0.6–1.5 mm long, with ca. 5–10 spikelets (male plants), or spikelets concealed within a ± globular, bur-like structure (female plants); plants colonial from stolons.

B. dactyloides