688 Mr. Brown on the Organs and Mode of 



pregnating many species belonging to different tribes of Orchi- 

 deae, by applying the pollen masses to the stigma, whose channel 

 communicating vvith the cavity of the ovarium, and first noticed 

 by Haller, he also describes. 



In 1827, Professor L. C. Treviranus* published an account 

 of several experiments made by him in 1824, which satisfacto- 

 rily prove that impregnation in this family may be effected by 

 the direct application of the pollen to the stigma. 



About the end of 1830 a letter from Professor Amicitto 

 M. Mirbel was published, in which that distinguished micro- 

 scopical observer asserts that in many phaenogamous plants the 

 pollen tubes, or hoyaux, penetrate through the style into the 

 cavity of the ovarium, and are applied directly to the ovula. 



In this important communication Orchideae are not men- 

 tioned, but M. Adolphe Brongniart in a note states that he 

 himself has seen the production of hoyaux or pollen tubes even 

 in this family ; that here, however, as well as in all the other 

 tribes in which he had examined these tubes, he found them 

 to terminate in the tissue of the stigma. 



Of the second class of authors the earliest is Linnaeus.]:, who, 

 in 1764, not satisfied either with his own or any other descrip- 

 tion then given of the stigma, inquires whether the influence 

 of the pollen may not be communicated internally to the 

 ovarium. 



In 1770, Schmidel§, in an account which he gives of a spe- 

 cies of Epipactis, describes and figures the upper lip of the 

 stigma, the rostellum of Richard, with its gland both before and 

 after the bursting of the anthera ; and as he denominates that 



* Zeitschrift f. Physiol, ii. p. 225. f Annal. des Sc. Nat, xxi. p. .S29. 



X Pralect. in Ord. Nat. ed. Giseke. p. 182. 



§ Gesn. Op. Bot. hist, plant, fasc. ii. p. 15. tab. 19. 



part. 



