1. Annual wiry-stemmed North American weed with minute scalelike leaves and small yellow flowers
   - orange grass, nitweed, pineweed, pine-weed

Type of: St John's wort

• Isoetaceae
• Isoetales
• Isoetes
• isoflurane
• isogamete
• isogamy
• isogloss
• isogon
• isogonal line
• isogone
• isogonic
• isogonic line
• isogram
• isohel
• isohyet
• isolable
• isolate
• isolated
• isolating
• isolation
• isolationism
• isolationist
• isolationistic
• isolator
• Isolde