There are about twenty-two, more or less unstable, forms of Eucalypts native of Tasmania which, may be regarded as distinct species. The variations of some of these are very puzzling to the student, and have been responsible for much confusion. Some of the species respond profoundly to change of conditions, especially soil.Hybridisation is fairly common with many species, and is responsible for some temporary confusion, and perhaps permanent change. There is a further evolution progressing in response to internal and unknown causes, not in the small fluctuating variation present in the offspring of every organism, but in sudden mutation. With some of our species, especially Blue Peppermint, from seed carefully gathered off the one tree, it is common to find conspicuous distinction of form amongst the offspring. There is a large field of research in all three forms of variability open to the student; very little has been done, and we shall not properly understand the limitation of species until it is.