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Baja Wild

• Thanks for the Support: The Epiphytes, Spanish “Moss” and Ball “Moss”

By Hans Bertsch
CONTRIBUTOR

With Thanksgiving Day approaching, we think of all who support us, but none more so than do the epiphytes—plants that live upon others! Getting all their moisture and nutrients from the air, they occur in North America's only fog desert, where wet west winds from the Pacific blow inland to San Borja, across the Vizcaino Desert and Magdalena Plains, and south to the Cape. They get nothing from the plants they grow on except living space, a room with a view. There are 2 common types in Baja California, both of which are misnamed “mosses.”
Spanish moss (Ramalina) is actually a lichen, growing on torote, cirio, and both ocotillos. Lichens are combo-plants, a partnership of microscopic photosynthesizing green algal cells living inside non-photosynthetic fungus cells. The alga makes and supplies sugars to the protecting fungus. Now that deserves a three-fold round of thanks. Orchilla (their Spanish name) looks like long, gray-green, well-used wigs. Scores of other species of lichens (with a totally different shape and lifestyle) are the orange, red, black, even silver-gray splotches of color one sees on rocks.
Ball moss (gallito or heno pequeño) also is no moss. It belongs to the pineapple and orchid family Bromeliaceae. The common BC species, Tillandsia recurvata ranges across the southern US (to Florida, where it is found on oak trees), México, and south to Brazil, Argentina and Chile, and on Puerto Rico and the Virgin Islands. It finds a space to squat on cacti, torote, cirio, and other plants. It is even found on telephone wires, emphasizing the air-borne source of moisture and nutrients.
The plant is a grapefruit-size ball-shaped tangled mass of thin, recurved (hence the species name) leaves. The sticky seeds are plumed, and can be dispersed by the wind or by being stuck to birds' feet or bills.
Recent research by Carlos Martorell and Exequiel Excurra (Oecologia 151: 561-573; 2007) explains the evolutionary adaptations of the leaves' shape. Fog-based water-collecting plants often have a rosette growth pattern, exposing all parts to the surrounding air. Many narrow and highly flexible long leaves increase Tillandsia's surface area exposed to the wet air, thereby maximizing the efficiency of trapping water. Wide-leaved rosettes can have only a few blades, which they proved experimentally would be far less efficient in fog-harvesting.
Although nitrogen is air's most abundant chemical, this “free” atmospheric nitrogen cannot be used by plants. They must have their nitrogen (N2) “fixed” into usable nitrates (NO3) by bacterial organisms in the soil. [Remember nitrogen's importance as a key component of amino acids and proteins!] Bacterial replenishes of soil nitrates are frequently attached to legume roots such as peas and lupine. Ball moss's air roots cannot access these soil nitrates. Interestingly, the desert epiphyte Tillandsia recurvata harbors the nitrogen-fixing bacterium Pseudomonas stutzeri inside its tissues, thereby getting its nitrates from an endophyte (epi = on, upon; endo = inside).
Chemicals in Tillandsia have been researched for anti-cancer and HIV/AIDS applications. Living plants have also been used to monitor heavy metal concentrations polluting the air in México City.
These epiphytes have lots to be thankful for—especially the support given them by their many friends and relatives. Gratitude should be a daily action, with Thanksgiving Day just a reminder of that. Thank you, my dear wife Rosa; and to my family, friends and you kind readers, let's keep supporting each other, thankfully.
Dr. Hans Bertsch, marine biologist, lives in Tijuana and Imperial Beach with his wife Rosa del Carmen Campay. He is the author of Sea of Cortez Marine Invertebrates, 2nd ed., and may be reached at: hansmarvida@sbcglobal.net