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. IV. of Australia, has been described and figured by Mr. Fitzgerald. The flowers are arranged on the spike in the same manner as in S. autumnalis; and the labellum with two glands at its base closely resembles that of our species. It is therefore an extraordinary fact that Mr. Fitzgerald could not detect even in the bud any trace of a rostellum or of viscid matter. He states that the pollinia touch the upper edge of the stigma, and fertilise it at an early age. Protecting a plant from the access of insects by a bell-glass made no difference in its fertility; and Mr. Fitzgerald, though he examined many flowers, never noticed the slightest derangement of the pollinia, or any pollen on the surfaces of the stigmas. Here then we have a species which fertilises itself as regularly as does Ophrys apifera. It would, however, be desirable to ascertain whether insects ever visit the flowers, which it may be presumed secrete nectar, as glands are present; and any such insects should be examined, so as to make certain that pollen does not adhere to some part of their bodies.

Listera ovata, or Tway-blade.—This Orchid is one of the most remarkable in the whole order. The structure and action of the rostellum has been the subject of a valuable paper in the 'Philosophical Transactions,' by Dr. Hooker, who has described minutely and of course correctly its curious structure; he did not, however, attend to the part which insects play in the fertilisation of the flowers. C. K Sprengel well knew the importance of insect-agency, but he misunderstood both the structure and the action of the rostellum.

The rostellum is of large size, thin, or foliaceous,