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 IN ORCHIDEiE AXD ASCLEPIADE^. 503

tliat dehiscence which, though very remarkable in this order, is in a great degree analogous to that taking pkace in most Cruciferee, in several Leguminosa', and in other families of plants. It may also be objected to j\Ir. Bauer's view of the composition of ovarium, that the arrangement of the parietal placentae, which on this hypothesis would occupy the axes of the three alternate comi)onent parts, is contrary to every analogy ; Avhile the position of the stigmata, if my account should prove to be correct, affords evidence nearly conclusive of the ovarium being formed of only three parts.

In those genera of OrchidccC in Avhich the lateral stamina are perfect, and the middle stamen without anthera, namely, Cypripedium and Apostasia, all these lobes or divisions of stigma are equally developed, are of nearly similar form and texture, and, as I have proved by direct experiment in Cypripedium, are all equally capable of performing the proper function of the organ.

In most other cases the anterior lobe, or that placed croi opposite to the perfect stamen, and deriving its vessels from the same cord, manifestly differs both in form and texture from the other two. To this anterior, or upper lobe, as it generally becomes in the expanded flower, the glands always belong to which the pollen masses become attached, but from w^hicli they are in all cases originally distinct, as may be proved even in Ophrydea?.

According to my view, therefore, of the mode of impreg- nation, its office is essentially dift'erent from that of the two lateral lobes or stigmata, which in various degrees of development are always present, and in all cases, when the ovarium is perfect, are capable of performing their proper function.

The greatest development of these lateral stigmata takes place in the tribe of Satyrinac or Ophrydeac, as in many species of Ilahenaria, those especially which are found near or within the tropics ; and still more remarkably in Bonatea sjieciosa, a plant hardly indeed distinguishable from the same extensive genus.

It would seem that in Bonatea the extraordinary develop- ment and complete separation of these lateral stigmata.

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