OK THE FERTILIZATION OF MEYENIA ERECTA. 



145 



On 



Mecl 



By E. Irwin - Lt^ch, of Kew Gardens. (Communicated 

 by Dr. J. Murie, F.L.S.) 



[Read April 18, 1878.] 



I haye the pleasure of bringing before the notice of the Society, 

 in the flowers of Meyenia erecta, a previously unobserved mecha- 

 nism to the end of cross-fertilization ; and by means of the ac- 

 companying woodcut I trust I shall be able in a few words to 

 convey a sufficiently intelligent description. The corolla is 

 funnel-shaped, slightly curved, and lies in a nearly horizontal po- 

 sition. The anthers are placed about midway in the tube, and 

 their backs are pressed against its upper wall. The style is 

 slender # and flexible ; it equals the tube in length, and runs 

 along a little groove, as it were, in the roof; so that the peculiar 

 stigma is placed just at the mouth and immediately over it. 



Now comes the most important part of the mechanism. The 

 stigma consists of two lips ; the upper is folded into a tube 

 and points straight forward. Through this lip alone is it pos- 

 sible for the pollen to fertilize the ovules. Pollen touching 

 the lower lip would seem here to be of no avail. "What, then, 

 is its use ? It will be seen, in contrast to the other, that it is 

 spread open and projects downwards over the entrance to the 

 tube ; and its use is to act as a lever, in this way : — If an insect 



Sketches of the flower of Meyenia erecta, to illustrate points connected with 

 its mode of fertilization. A. Flower from above, foreshortened view. B. 

 Lateral view of the flower in section, showing position and form of pistil and 



stamens. These two figures are about natural size. 0. Anther, enlarged. 

 D. An ideal transverse section to show the relative positions of pistil and 

 stamens. 



* In the drawing somewhat stouter than obtains in the natural object. 



