One for the Record

Natural History, Nov, 2007 by Erin Espelie

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When the poet William Cullen Bryant wrote that the "loveliest of lovely things are they on Earth that soonest pass away," he could easily have been describing orchids. Although experts agree that they've brightened the planet for millions of years and now number well over 20,000 species, the ephemeral plants have never appeared in the fossil record ... until now.

An ancient stingless bee was found trapped in a piece of amber 15 to 20 million years old, with a precious few packets of orchid pollen clamped to its back. That singular plant-and-pollinator duo enabled Santiago R. Ramirez, a graduate student at Harvard University, and several colleagues to make previously impossible determinations about orchid evolution.

On the basis of the shape and packaging of the pollen grains, Ramirez positioned the orchid--Meliorchis caribea, a species new to science--on a phylogenetic tree. He then calibrated the tree with existing molecular data from the rest of the orchid family. Orchids, he found, started diversifying about 65.5 million years ago, from a common ancestor that probably arose some 80 million years ago. That means the original lovelies may have bloomed alongside the dinosaurs--much earlier than most orchid biologists had thought. (Nature)