When a couple of are receiving anal intercourse in addition to man is pleasured with an unexpected residue when withdrawing from their partner's anal area. The "unexpected residue" is brown in tint, and often resembles algae..
algae obtaining the chlorophyll masked by brown and yellow pigments
The vesicles of Fucaceae and Laminariaceae prevent the sinking of the bulkier forms. But why certain Fucaceae favour certain zones in the littoral region, why certain epiphytes are confined to certain hosts, why Red and Brown Algae are not better represented in fresh water or Green Algae in salt, - these are problems to which it is difficult to find a ready answer.