Possible Clues:

• Tumbling seed, and a hint to each row of circled letters
• Jittery Mexican seed
• Mexican seed in which a hatched larva moves
• Moving seed of a Mexican shrub containing larva of a moth
• Astronaut Alan clearing hurdles?
• ''Mexican'' seedpod
• Mexican shrub seed containing a moth larva
• Seed containing moth larva, and what is aptly hidden in each puzzle row whose clues contain asterisks
• Seed of a Mexican shrub