From 2speccers2tools wiki

The screengrass is a cosmopolitan genus of microbe that evolved due to the still-increasing levels of background radiation, mainly due to the sea turdles and baleenusi present in the ocean. They are more densely-packed than thin cellular mats due to their colonial structure. When a lone screengrass cell (either emitted off the top of the colony as a spore, or simply broken off) touches substrate, it will grow stiff flagella in order to stay in place. Like their ancestors they can tolerate an extreme variety of habitats, allowing them to thrive near places such as the horrible rectangle island. Inland varieties usually live in rivers, since they can't grow on dry land (although they can survive even in a mere puddle).