What is tunica in plant biology?
In biology, a tunica (/ˈtuːnɪkə/; UK: /ˈtʃuːn. ɪ. kə/) (plural tunicae) is a layer, coat, sheath, or similar covering. … In biology one of its senses used to be the taxonomic name of a genus of plants, but the nomenclature has been revised and those plants are now included in the genus Petrorhagia. What are…