1. Not having a floral envelope or perianth

Antonym: chlamydeous

• in vitro
• in vivo
• in vogue
• in writing
• in your birthday suit
• in-basket
• in-between
• in-bounds
• in-chief
• in-depth
• in-fighting
• in-house
• in-joke
• in-law
• in-line skate
• in-migration
• in-person
• in-service
• in-situ
• in-tray
• in-your-face
• inability
• inaccessibility
• inaccessible
• inaccessibly