Related Clues:

• Growth on stones
• Primitive water plant
• Bit of seafloor flora
• Tiny pond plant
• Seaweed
• Velvety ground cover
• Kelp, e.g.
• Reef denizen
• Aquarium growth
• Velvety tree hugger
• Velvety flora
• Sea moss constituent
• Pool life form
• Sea lettuce, e.g.
• Rock cover