1. A weedy perennial with tough wiry stems and purple flowers; native to Europe but widely naturalized
   - lesser knapweed, black knapweed, hardheads

Type of: knapweed

• roselle
• Rosellinia
• rosemaling
• rosemary
• roseola
• roseola infantilis
• roseola infantum
• roset
• Rosetta Stone
• rosette
• rosewood
• rosewood tree
• Rosh Chodesh
• Rosh Hashana
• Rosh Hashanah
• Rosh Hashona
• Rosh Hashonah
• Rosh Hodesh
• Rosicrucian
• Rosicrucianism
• rosid dicot family
• rosid dicot genus
• Rosidae
• rosilla
• rosily