Catalogue › TreesAlder (Alnus)Every species of the genus Alnus in the catalogue.Red alder (Alnus rubra)Brook alder (Alnus maritima)Alder (Alnus glutinosa)Grey Alder (Alnus incana)White alder (Alnus rhombifolia)Wavy-leaved or Sitka Alder (Alnus sinuata)Mountain Alder (Alnus tenuifolia)American Green Alder (Alnus viridis crispa)