Downy Brome: seed-heads are very dense and often purple tinted.

• A. Prickly Pear
• B. Larkspur
• C. Russian Thistle
• D. Downy Brome

Answer: (D)

Seed-head morphology helps you identify rangeland weeds, and Downy Brome has a distinctive dense, compact seed-head. The heads are very tightly branched into a compact panicle, and as the seeds mature they often take on a purple tint. That combination—dense, compact seed-heads with a purple hue—is a telltale sign of Downy Brome and sets it apart from the others.

Prickly pear is a cactus and doesn’t produce a grasslike seed-head. Larkspur has tall flower stalks with showy flowers and later seed pods, not a dense grass panicle. Russian thistle forms a loose, branched, tumbleweed-like seed head, not a dense, purplish head.