Pronunciation: (hī"pu-thal'us, hip"u-), [key]
—pl. -thal•liPronunciation: (-thal'ī). [key]
1. a layer of hyphae rimming the thallus of certain lichens.
2. a filmlike residue at the base of the sporangia of certain slime molds.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.