In Guyanese savannas, a fungus infects grasslike plants, sterilizes them and produces bizarre all-fungal “flower” doppelgängers
By Priyanka Runwal on February 2, 2021
On a collection trip to Guyana in 2006, botanist Kenneth Wurdack was strolling along an airstrip at Kaieteur National Park when he noticed something unusual about the flowers on two species of yellow-eyed grasses. Unlike the species’ typical blooms, they were a more orange shade of yellow, tightly clustered and spongy in texture. “I just sort of filed it away as an incidental thing,” Wurdack says.10 Sec
On subsequent trips, he observed more examples of the strange phenomenon. Digging through relevant botanical literature, Wurdack learned what was actually going on: The orange oddities were not really flowers at all. And the yellow-eyed grasses—which belong to a genus called Xyris—had not made them.
Instead they were mimics—the product of a fungus that Wurdack, who works at the Smithsonian National Museum of Natural History, and his colleagues recently described. The fungus, Fusarium xyrophilum, infects an Xyris plant and sterilizes it to block the plant’s own blooms. Then F. xyrophilum hijacks an as yet unknown aspect of the plant’s operations to host pseudoflowers made entirely of fungal tissue—potentially tricking pollinators to disperse its spores rather than pollen from the plant’s flowers. The finding is thought to be a first of its kind on record.