Slenderflower thistle, <i>Carduus tenuiflorus,</i> fruits are single-seeded achenes, and may either have long bristles (as shown here) or may lack bristles.
Slenderflower thistle, Carduus tenuiflorus, fruits are single-seeded achenes, and may either have long bristles (as shown here) or may lack bristles.
Credit: James A. O'Brien