What is a clear, viscous, tasteless substance extracted from the mucilaginous sap of the mistletoe (Viscum album), holly, etc., and constituting an essential ingredient of birdlime called?

viscin — A clear, viscous, tasteless substance extracted from the mucilaginous sap of the mistletoe (Viscum album), holly, etc., and constituting an essential ingredient of birdlime. (Webster's 1913.)

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