viburnum: deciduous or evergreen shrubs or small trees: arrow-wood; wayfaring tree
asterid dicot genus: genus of more or less advanced dicotyledonous herbs and some trees and shrubs
fluorescein: a yellow dye that is visible even when highly diluted; used as an absorption indicator when silver nitrate solution is added to sodium chloride in order to precipitate silver chloride (turns pink when no chloride ions are left in solution and negative fluorescein ions are then absorbed)