Related Clues:

• Forest floor growth
• It grows on rocks
• Damp area growth
• "A rolling stone gathers no ___"
• Fungus-alga union
• Velvety green growth
• Reindeer moss, e.g.
• Shady growth
• 'A rolling stone gathers no ....'
• Tiny plants found on rocks, tree-trunks etc
• Crusty, tufty growth on trees and stones
• Tiny plant found on rocks and trees
• Small plants found on tree-trunks and stones
• Tiny plants growing on rocks and treetrunks
• Stirling . . . ., Kate . . . .