Related Clues:

• Spirogyra, e.g.
• Bryologist's interest
• Forest-floor cover
• Lake organism
• Bit of ocean life
• Primitive plant
• Simple aquatic organism
• Birdbath organism
• Plant that can grow on trees
• Woodsy growth
• Jarvis of the Denver Broncos
• Fish tank organism
• Tree trunk growth
• Kelp, for one
• It grows on trees