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 Rh, whose place in the system is, indeed, not yet determined, but of which the habit is nearly that of Rhodolæna, seems in some degree to confirm M. du Petit Thouars's opinion of the near relation of Chlenaceæ to Tiliaceæ; though M. de Jussieu, in placing it between Ebenaceæ and Rhodoraceæ, appears to take a very different view of its affinities.

MALVACEÆ. Of this family 18 species were observed on the banks of the Congo. It forms, therefore, about one thirty-fourth part of the phænogamous plants of the collection; which is somewhat greater than the equinoctial proportion of the order, as stated in Baron Humboldt's dissertation, but nearly agrees with that of India, according to Dr. Roxburgh's unpublished Flora Indica.

The greater part of the Malvaceæ of the collection belong to Sida and Hibiscus; and certain species of both these genera are common to India and America. Urena Americana and Malachra radiata, hitherto supposed to be natives of America only, are also contained in the collection; and [429 the loftiest tree seen on the banks of the Congo, is a species of Bombax, which, as far as can be determined from the very imperfect specimens preserved in the herbarium, does not differ from Bombax pentandrum of America and India. I have formerly remarked that Malvaceæ, Tiliaceæ, Hermanniaceæ, Buttneriaceæ, and Sterculiaceæ, constitute one natural class; of which the orders appear to me as nearly related as the different sections of Rosaceæ are to each other. In both these, as well as in several other cases that might be mentioned, there seems to be a necessity for the establishment of natural classes, to which proper names, derived from the orders best known, and differing perhaps in termination, might be given.

It is remarkable that the most general character connecting the different orders of the class now proposed, and which may be named from its principal order Malvaceæ, should