The Cow Horn Orchid
Myrmecophila orchid (Orchid Family)
Myrmecophila tibicinis (Orchidaceae)
A “myrmecophile” is a living organism which has some association with ants where the orchid genus Myrmecophila gets its name. Comprised of several species distributed throughout Mexico, the Caribbean, and Central America, Myrmecophila is a genus of epiphytic orchids that has evolved a very interesting strategy for acquiring the nutrition it needs to photosynthesize. It’s beautiful, too, and fun to grow - the stunning flowers are borne on very long (easily over a meter) spikes, which can take months to form. At Marie Selby Botanical Gardens, New World epiphytic orchids are the main area of research. We are very interested in what makes an epiphyte an epiphyte, and in the adaptations that these plants have evolved as they left the soil for the treetops.
In case you’re not aware, an epiphyte is a plant which grows upon another plant, but does not derive sustenance from it (as opposed to a parasite). Many epiphytes are mistakenly called “air plants” on the belief that they derive all of their sustenance from the air. While it’s true that they do pull humidity out of the tropical air as a water source, nutrition is a different story. Plants make their own food in a process called photosynthesis, which requires sunshine, water, and certain nutrients. The canopy of a tropical forest has so little to offer in the area of nutrition that plants which live there have had to come up with some remarkable adaptations. Bromeliads and pitcher plants have developed tanks which can trap bird droppings, leaf litter, even small mammals, and use their carbon. Epiphytic orchids developed long, velamentous roots -- specialists at slurping up nutrient-filled rain water, and pseudobulbs which can store water during dry periods.
Myrmecophila species, like many epiphytic orchids, are comprised of structures called pseudobulbs. Each year, the orchid pushes new growth: at first, full of leaves that feed the plant; then a bloom spike which is how the plant reproduces; followed by a leafless, bulb-like structure the next year. While many orchids use years-old structures for storing water, the older pseudobulbs of Myrmecophilas are hollow. Ants colonize these structures and set up small civilizations. The orchid provides the ants with nectar from its flowers and shelter from the rain, and in return the ants fill up the pseudobulbs with their garbage. Dead ants, sand, soil, bits of food, ant poop…these “garbage dumps” provide the orchid with the same basic nutrition that most plants get from having their roots in the soil. Just in this case, the soil is in the plant, not the other way around. Here at Selby Gardens we have several Myrmecophilas in spike, hanging from some of our larger blooming trees on the Great Lawn.
Text and photo by David Troxell