Finnish Biodiversity Information Facility
Taxonomy database of the U.S. National Center for Biotechnology Information
Global Biodiversity Information Facility
Burke Herbarium Image Collection: Vascular Plants, Macrofungi, & Lichenized Fungi of Washington
Online Field Guide to the Rare Plants of Washington
Interim Register of Marine and Nonmarine Genera
Open Tree of Life reference taxonomy version 3.2
Botanical Society of Britain and Ireland
Royal Horticultural Society Plant Database