Page:Miscellaneousbot01brow.djvu/534

 516 ON THE ORGANS AND MODE OF FECUNDATION

��ASCLEPIADE/E.

The various statements and conjectures on the structure and functions of the sexual organs in tliis family were collected, and published in 1811, by the late Baron Jacquin, in a separate volume, entitled, ' Genitalia Asclepiadearum Contro versa.'

To this work, up to the period when it appeared, I may refer for a complete history, and to the tenth volume of the Linnean Society's Transactions, along with the first of the Wernerian Natural History Society's Memoirs, published somewhat earlier, for a slight sketch, of the subject.

I shall here -therefore only notice such statements as Jacquin has either omitted or imperfectly given, and continue the history to the present time.

In 1763, Adanson correctly describes the stamina in Asclepias as having their filaments united into a tube surrounding the ovaria, their antheriE bilocular and cohering with the base of the stigma, and the pollen of each cell forming a mass composed of confluent grains as in Orchi- dese. He is also correct in considering the pentagonal body as the stigma ; but he has entirely overlooked its glands and processes, nor does he say anything respecting the manner in which the pollen masses act upon or com- municate their fecundating matter to it.

In 1779, Gleichen,-^ although he expressly says that in young flower-buds the pollen masses are distinct from those glands of the pentagonal central body to which they 716] afterwards are attached, yet considers both masses and glands as equally belonging to the anthera, the mass being the receptacle of the pollen. He further states that before the masses unite with the glands they are removed from the cells in which they were lodged, and are found firmly implanted by their sharp edge into the w^all of the tube which surrounds the ovaria ; that in this state a white

' Microscoji. l^/iid. p. 73, et seq.

�� �