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 118 until the extrication is complete, when expansion takes place.

It is singular that this mode of cohesion between the ovarium and calyx in certain genera of Melastomaceæ, and the equally remarkable æstivation of antheræ accompanying it, should have been universally overlooked, especially in the late monograph of M. Bonpland; as both the structure and economy certainly exist in some, and probably in the greater part, of the plants which that author has figured and described as belonging to Rhexia.

On the limits, structure, and generic division of Melastomaceæ, I may remark—

1st. That Memecylon, as M. du Petit Thouars has already suggested, and Petaloma of Swartz both belong to this order, and connect it with Myrtaceæ, from which they are to be distinguished only by the absence of the pellucid glands of the leaves and other parts, existing in all the genera really belonging to that extensive family.

2ndly. There are very few Melastomaceæ in which the ovarium does not in some degree cohere with the tube of the calyx; Meriana, properly so called, being, perhaps, the only exception.

And in the greater number of instances where, though the ovarium is coherent, the fruit is distinct, it becomes so from the laceration of the connecting processes already described.

3rdly. That the generic divisions of the whole order remain to be established. On examination, I believe, it will be found that the original species of the Linnean genera, Melastoma and Rhexia, possess generic characters sufficiently distinguishing them from the greater part of the plants that have been since added to them by various authors. In consequence of these additions, however, their botanical history has been so far neglected, that probably no genuine species of Melastoma, and certainly none of Rhexia, has yet been published in M. Bonpland's splendid and valuable monographs of these two genera.