The Sub-section Albidae, the only major taxomonic grouping of Populus immune to both Melampsora larici-populina Kleb and M. medusae Thum, leaf rusts in the field in Australasia, is worthy of fuller investigation for use in commercial and aesthetic plantings. Preliminary investigations indicate that race-specific resistance is common in the Aigeiros Section of Populus and this has significant implications in the establishment of clones of this Section. Rust resistance, disease progress pattern and length of growing season of clones are important considerations in the selection of clones for certain purposes in particular environments. {\textcopyright} 1980 Taylor & Francis Group, LLC.