Desert moss slurps water from its leaves, not roots

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From California to China, desert moss (Syntrichia caninervis) braves life in hot deserts and still stays hydrated. What’s its secret? The moss gathers water via a topsy-turvy collection system in its leaves.

Moss leaves have tiny hairlike points at their ends called awns. Previous evidence pointed to a potential role for the awns in water collection and prompted Tadd Truscott of Utah State University and his colleagues to zero in on the structures.

Imaging exposed a system of barbs that line the awns and catch tiny airborne water droplets, the team reports June 6 in Nature Plants. When the air is misty, foggy or the least bit humid, trapped dewdrops move up grooves in the moss leaves by capillary action. The tiny drops form a bigger drop to be absorbed and stored by the plant. When it rains, moss awns reduce splash and capture raindrops by the same mechanism.

Most desert plants, especially cacti, get their water from roots, but moss may not be the only plant that uses unique leaf structures to stock up on water, the team argues.