1. periodic shedding (of leaves).   Hint First letter clue   2. fragrant or sweet-smelling.   First letter clue   3. tending to a center.   First letter clue   4. salty or saline.   First letter clue   5. damp or moist.   First letter clue   6. sealed by fusion to be air-tight.   First letter clue   7. having a fixed order or nature.   First letter clue