Wilfrid Laurier Herbarium (Biology)
Found: a new species of parasitic plant in Michoacán, Mexico
Dodders (Cuscuta spp.) are fascinating parasitic plants. Unlike many other plants, dodders are known by people everywhere in the world. Even in a lost village in South America one can ask politely (in Spanish, of course): “Have you seen something that looks like yellow spaghetti spread on other plants?” and people’s faces will light up: “Yes, yes, that thing that sucks the life out of corn, avocado. . .” (or any other plant for the matter). This is because dodders are unlike any other plants. The yellow-orange stems are leafless and thin; they twine around the stems of the plants that they parasitize; they form specialized structures called haustoria that puncture the hosts’ tissues and then proceed to extract water, carbohydrates, and other solutes. The connection between host-parasite is so tight that in medieval Europe it was believed that the parasite was part of the plant host, and that together they formed “a monstrosity,” a metamorphosis of the “normal” species. Common names of Cuscuta worldwide illustrate the mixed reverence and fear with which people have regarded these plants: devilguts, devil's hair, devil’s ringlet, goldthread, hailplant, hairweed, hell bind, love vine, pull down, stranglevine, strangleweed, tangle gut, witches' shoelaces, and so on.
In collaboration with Sasa Stefanovic from UFT, Mississauga, we have been studying the evolution and taxonomy this group of plants for the last three years. More than 10,000 herbarium specimens from all continents have been sent to us for study. One of these specimens from the University of California Herbarium at Riverside, collected from Michoacán, Mexico, drew my attention through its peculiar morphology of flowers and fruits. The specimen had the potential to be a new species, but more plant material was needed. I contacted the collector of this herbarium specimen, Ignacio García Ruiz from CIIDIR Michoacán (Centro Interdisciplinario de Investigacion para el Desarrollo Integral Regional Michoacán del Instituto Politécnico Nacional), and asked for his help. He kindly accepted to guide us through the mountains of Michoacan where he had collected the specimen.
During mid February 2007, with senior biology student Mark Welsh, I left behind a Canada white with snow. Soon we were contemplating the vastness of Mexico’s sunny landscapes from the little window of our American Airlines flight. It didn’t matter that our luggage failed to arrive in Guadalajara along with us. We rented a car and drove south towards Lake Chapala, which we circled, gazing at the slopes with blue plantations of Agave tequilana. We arrived in Jiquilpan at night, a little awed by everyone on the streets, laughing, eating, drinking, although it was only a Thursday. Next day we met our guide and host, Ignacio, and Eleazar Caranza, the local specialist in Convolvulaceae who came from Patzcuaro to meet us.
Michoacán de Ocampo (from michamacuan, Nahuatl for "the place of the fishermen") is a vast inaccessible wilderness with thousands of nameless volcanoes, sierras and barrancas. Roads are scarce; villages remote and isolated; people are poor, but very warm. Some regions remain unexplored even by the local botanists, not only because of the unforgiving topography of land, but also because of the bandidos who have taken advantage of this geography to hide and cultivate Cannabis and opium poppy. Despite a heavy military presence, Michoacán has remained one of the deadliest Mexican state, with more than 500 people killed in 2006 of a population of only 4 million.
Yet the plant diversity is astonishing. Ignacio joked that “aqui tenemos una desbandada floral total” (“we have here an absolute floral chaos”). Indeed, epiphytic orchids, bromeliass and various vines hang from the trees; countless flowering plants grow in a huge variety of habitats. This is the heaven for any botanist!
For a week we explored the hauntingly beautiful Michoacan, asking local inhabitants if they had seen dodders. We found the new species in Sierra de Cotija, and we collected sufficient material to send duplicates to other herbaria. We have fixed floral buttons for chromosome studies and fragments of plants in silica gel for DNA extraction. Soon we will submit this work for publication together with our Mexican colleague. And perhaps even more important, we have found great friends and discovered a new vibrant world.
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