A Year of Moss: Week 4

Moss frozen solid after a freezing rain in the Portland metro area

 You'll notice that even after cold temperatures, a lot of moss stays green and healthy-looking. How does moss survive the cold? 

I found a great summary on MontanaNaturalist.org. Some excerpts from the post: "Mosses, like liverworts and hornworts, are bryophytes. In contrast with vascular plants that contain xylem, a tissue used to transport water internally, bryophytes instead absorb water and nutrients through their leaves… research suggests that moss also has antifreeze properties! Ice crystals can rupture cell walls, causing the cell—and eventually the animal or plant—to die. Some scientists believe mosses contain a combination of sugars and sugar alcohols that become more concentrated in the fall and winter and stop the ice crystals from developing, much like how antifreeze regulates temperature in a car. There’s some speculation about whether the moss itself has the antifreeze property or whether it’s secreted by bacteria living on the surface of the moss; either way, the result is that the sugar alcohols melt the snow around it."