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which is thus temporarily imprisoned within the otherwise almost completely closed flower. The labellum

Fig. 14.

Pterostylis longifolia. (Copied from Mr. R. D. Fitzgerald's 'Australian Orchids.')

A. Flower in its natural state: the outline of the column is dimly seen within.

B. Flower with the near lateral petal removed, showing the column with its two shields, and the labellum in the position which it occupies after having been touched.

remains shut from half an hour to one hour and a half, and on reopening is again sensitive to a touch. Two membranous shields project on each side of the