29 July 2016
Vol 353, Issue 6298

About The Cover

Cover image expansion

COVER Hypogymnia imshaugii, a macrolichen common in northwestern North America. Lichens were previously thought to contain two parts: an ascomycetous fungus and a photosynthetic alga. Spribille et al. show that a third element–a basidiomycete yeast–is part of the lichen cortex in the largest group of macrolichens. See page 488.
Photo: Timothy B. Wheeler/