1. Small clustering cactus of southwestern United States; a threatened species
   - Pediocactus knowltonii

Type of: cactus

Part of: genus Pediocactus, Pediocactus

• rydberg unit
• Rydberg's penstemon
• rye
• rye bread
• rye ergot
• rye whiskey
• rye whisky
• ryegrass
• Rynchopidae
• Rynchops
• ryot
• Rypticus
• Ryukyu Islands
• Ryukyuan
• Réaumur
• réchauffé
• rémoulade
• röntgen
• s
• S wrench
• S-shape
• s-shaped
• S. S. Van Dine
• S. Smith Stevens
• SA