Member states extend throughout the Americas and from Australasia to Europe.
Group Membership in any country or geographic region may be assumed by any one of the following bodies - the National Academy, the National Research Council, a similar institution, or an association or group of scientific institutions or societies. Each Group Member appoints one Group Delegate to the International Council of the Union, where the Group Delegate has the right to vote, provided the current subscription of the Group Member has been received by the Treasurer.