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6

OPHREÆ.

the following volume I have followed, as far as I conveniently could, the arrangement of the Orchideæ given by Lindley. The British species belong to five of his tribes, the Ophreæ, Neotteæ, Arethuseæ, Malaxeæ and Cypripedeæ, but the two latter tribes contain each only a single genus. Various British and foreign species belonging to the several tribes are described in the first eight chapters. The eighth also contains a discussion on the homologies of the flowers of the Orchideæ. The ninth chapter is devoted to miscellaneous and general considerations.

The Ophreæ include most of our common British species, and we will begin with the genus Orchis. The reader may find the following details rather difficult to understand; but I can assure him, if he will have patience to make out the first case, the succeeding ones will be easily intelligible. The accompanying diagrams (fig. 1, p. 8) show the relative position of the more important organs in the flower of the Early Orchis (O. mascula). The sepals and the petals have been removed, excepting the labellum with its nectary. The