It is generally known that botanical nomenclature, though sprung from mediaeval scientific Latin, and agreeing, in its orthography for the greater part, in its grammar as much as possible, with classical Latin, shows countless forms which not only from a classical-grammatical, but also from a mediaeval-grammatical point of view, must be looked upon as errors. These errors are for the greater part due to an inadequate knowledge of Latin and Greek grammar, or to indifference or lack of good taste on the part of botanists. And since a botanist cannot be expected to abstain from giving new names to plants until in the opinion of philologists he is sufficiently acquainted with Latin, Greek and other languages which he may have to use, it is unavoidable that the number of philological mistakes in botanical nomenclature should be steadily increasing. It may be disputed whether the mistakes should be corrected, or whether, granting the desirability, such a thing is impossible. The present author was at one time convinced that correction ought to take place systematically, but after some attempts to contribute to it he realised that it was impossible to carry it through in a consistent manner without detriment to botany, and that a non-consistent or a consistentpartial correction would also cause difficulties without giving satisfaction. In any case great indulgence is desirable towards the countless mistakes that have been made in good faith. This, however, does not alter the fact that it is in all respects desirable to avoid such mistakes in future to the best of our knowledge.