soft tree fern: of Australia and Tasmania; often cultivated; hardy in cool climates
tree fern: any of numerous usually tropical ferns having a thick woody stem or caudex and a crown of large fronds; found especially in Australia and New Zealand; chiefly of the families Cyatheaceae and Marattiaceae but some from Polypodiaceae
unilateralism: the doctrine that nations should conduct their foreign affairs individualistically without the advice or involvement of other nations