Related Clues:

• It needs only one cell to have the makings of a gala
• A water gala
• Is the gala broken till all is green?
• We'd be in the water, by the sound of it
• Gala for the green
• Not the scum of the earth for the gala
• That's enough to make the gala sludgy (4)
• Gale for the Greens?
• Plant for a lag as primitive as this
• It's got one cell for the water gala
• The growth of the gala
• The sort of gala one might have in 13 across
• Seaweed, e.g
• Mussel morsel
• Aquatic eukaryote