Expansive live oaks dripping with spanish moss–a quintessential scene of the southeastern United States.
Contrary to the common name they are not actually a moss, rather a flowering plants in the Bromeliad family. They can reproduce from seed or by chunks moved by wind or birds, who use them for nest building. Their arboreal tangles provide important habitat for a wide diversity of arthropods including a highly specialized jumping spider which appears to only live in spanish moss.
Spanish moss (Tillandsia usneoides) live a pretty strange life style, for a plant. As “air plants” they spend their whole lives draped over tree branches far from anything resembling soil. So despite inhabiting only wet semi-tropical regions they are at serious risk of desiccation. To combat this they have a specialized water efficient form of photosynthesis called CAM Photosynthesis. This is the same trick that cacti use to conserve water. Up in the trees spanish moss must also find nutrients. Instead of having roots their long slender leaves are covered in scaly hairs that can absorb nutrients and water. Nutrients comes through rainwater and dust and also from the trees they inhabit. They are not stealers like parasitic mistletoe, rather, they soak up what washes out of tree bark and leaves. This source of nutrients is important enough that trees which leach few nutrients do not provide suitable habitat for spanish moss.
Spanish moss is also quite useful to humans. Up until the advent of synthetic fibers spanish moss was harvested from the ground after storms or directly from trees, then heaped into piles to decompose for a few weeks leaving just the dark elastic cords that make up the plants’ center. These were dried and cleaned, then used to stuff mattresses, car seats, or spun into rope, just to name a few uses. Spanish moss is also potentially useful as a simple way to monitor air pollution. Because they absorb particulates from the air which then accumulate in their tissues, measuring levels of toxic substances like Mercury in spanish moss may provide an accurate measure of air pollution in the area.
The South provides many natural history gems, but the ones hanging from the trees are among my favorites.
Photos taken on Sapelo Island, Georgia