The Malaxis paludosa, or Bog Malaxis, the smallest of British Orchids, is a rare plant, and differs from all of them in having its labellum turned upwards instead of downwards. Its lower margin clasps the column, making the entrance into the flower tubular. In this orchis the upper sepal and two upper petals are reflexed, to allow insects freely to visit the flower. In many orchids the labellum is properly directed upwards, but assumes its usual position as the lower lip by the twisting of the ovarium, or pedicel, of the flower. In the Malaxis paludosa, however, the twisting has been carried to such an excess, that the flower occupies the same position it would have held if the ovarium had not been twisted at all, and which the stalk ultimately assumes when ripe by the process of gradual untwisting. This little plant belongs to a genus distinguished by having a movable and deciduous anther, and is one of the British orchids that have allied forms among the exotic genera. All Dr. Lindley’s vast tribes of Epidendreæ, and the still more numerous and splendid Vandeæ, have not a single British representative. The structure of the exotic orchids is often very complicated, and they possess many properties unknown in the British genera. Their labellum, or lower lip, is so varied, and sometimes so singular, that it baffles description; besides, it often possesses peculiar motions, sometimes from structure, at other times from irritation. In the Bolbophyllum Rhizophoræ, the labellum is attached to the column by a very narrow thin strap, elastic as india rubber, which oscillates in a singular manner; while that of the B. barbigerum has a beard of fine hairs in almost constant agitation. The irritability of the labellum in many of the allied forms of the orchids is one of their remarkable properties; the slightest touch sets them into motion. The Australian genus Caleana possesses it in the highest degree; for when an insect settles on its labellum, it suddenly shuts up against the column, and encloses it, as it were, in a box.