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Readers of Perspectives may recall seeing a photograph of a Rafflesia bloom similar to this one several issues ago, in an article on parasitic plants. Rafflesia species, which have no roots, leaves, or stems, grow as a fungus-like strand inside a host vine for years before eventually developing a bud on the exterior of the host. Their flowers are the world's largest and smelliest, reaching three feet in diameter, weighing up to 15 pounds, and packing an olfactory punch with a stench like that of rotting flesh. The genetic lineage of Rafflesia has been a scientific mystery. But earlier this year, Harvard biologist Charles Davis and SIUC biologist Daniel Nickrent got national attention for publishing the answer to the puzzle in Science magazine. Using DNA sequencing, they determined that this genus is part of the family Euphorbiceae. Ironically, that family includes many species known for very small flowers, such as poinsettias (whose red bracts are not part of the flower) and castor bean plants (whose flowers have no petals). Apart from the basic scientific knowledge the team gained, a better understanding of the genetic mechanisms underlying floral gigantism could help researchers in agriculture and horticulture, where there is much interest in growing bigger flowers, Nickrent says. For more about Nickrent's research, see Freeloaders. Comments: Perspectives Webmaster
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