Plant conservation has got off to a late start. Many undescribed species are certainly already extinct, their value unknown. Professor Heywood argues that, because both the losses and the potential are greatest in the tropics, attention must focus there first. Less than one per cent of tropical lowland forest is in national parks or reserves, and there are many areas where little of it may be left even by 1990. This article is the substance of Professor Heywood's talk to the ffPS at last year's Annual General Meeting.