Related Clues:

• Pond dweller
• Nonflowering plant
• Sargassum, e.g.
• Simple water dweller
• Marine growth
• It creates energy through photosynthesis
• Rootless plant
• Seaweed and kelp, e.g.
• Bit of pond scum
• Birdbath greenery?
• Chlorophyllous organism
• Sea moss, for one
• Plankton part
• Aquarium organism
• Pool-owner's problem