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10 Andreas Cæsalpinus was born at Arezzo, in Tuscany. He published his great work, entitled, "Cæsalpini de Plantis libri sexdecim," in the year 1683. He framed his system on the Fruit and Corculum, which displays much ingenuity. And at that period the sixteen classes into which he divided it, comprehended all such plants as were then known. This plan answered very well, as far as the knowledge of plants extended at that time; but, as the Science advanced, it was found that many plants could not be referred to any of his divisions, and that induced the next eminent person whose performance we have now to consider, Robert Morrison, to publish his System, which he framed on the formation of the flower, and the general external habits of plants. His definitions are very often exceedingly erroneous, and have been the cause of much dispute. He distributed his system into eighteen classes.

If our time permitted, we might enter into a long account of the Systems of Herman, Ray, Rivinus, and others. Tournefort‘s continued so much in repute, that I will just advert to it, and afterwards pass on to that of Linnæus, and de Jussieu:—

Joseph Pitton de Tournefort was born in 1656. In the early part of his life he showed great traits of genius; he would steal from school to study Nature, which, in after years, he followed up by travelling through the Continents of Europe and Asia, and was subsequently chosen Professor of Botany at Paris. This celebrated Naturalist founded his System chieﬂy on the form, regularity, and number of petals of the corolla; and, although he has evinced great assiduity in distributing his classes, yet all systems founded on the corolla alone must fail, because that part of a plant is subject to great variation, dependent for the most part on adventitious circumstances. For the information of my auditors, I will advert to the table which shews his arrangement, and which was followed by all the Professors of Europe of his time, and is to this day quoted by some. The limits of the Lecture will not admit of our dilating too diffusely on the comparative merits of these Systems, and we shall now examine those of Linnæus and de Jussieu.

Linnæus, who spent the early part of his life in great difficulty, and whose brilliant genius at last overcame all obstacles, first formed a System, on the figure, duration, &c. of the calyx or ﬂower cup; after a time he found many plants that could not be referred to it, and it was not till then that he