Morison's writings evoked severe contemporary criticism, more on account of their manner than of their matter. His constant reference to the "_Hallucinationes_" of Caspar Bauhin especially, was considered to be offensive even if warranted, for every botanist admitted a debt of gratitude to the author of the _Pinax_. Equally resented was Morison's oft-repeated statement that he had drawn the principles of his classification, not from the works of other writers, but from the book of Nature alone. It was urged against him that he had failed to do justice to his predecessors, particularly to Cesalpino: and it must be admitted that there is unfortunately some truth in this allegation. Morison's indebtedness to Cesalpino is suggested by the fact that the nature of the fruit, and in a secondary degree that of the flower, was the basis of both their methods. From a comparison of the two systems, as set out in this lecture, their fundamental resemblance can be traced through the many differences of detail. Since Morison does not quote Cesalpino in his books, it might be inferred that possibly he had not read him. But there is convincing evidence to the contrary. There is the fact that Morison's preface to the _Historia_ contains a sentence taken _verbatim_, without acknowledgment, from the dedication of Cesalpino's _De Plantis_. Further, there is in the Library at the Oxford Botanic Garden a copy of the _De Plantis_containing many marginal notes which could not have been written by any one but Morison. The explanation of the position is probably this, that Morison regarded his classification as so great an advance upon that of Cesalpino, that he did not think it necessary to acknowledge what still remained of the earlier writer's work: but in any case his omission to mention Cesalpino was a grave error of judgment.