Fecundation in Orchidece and Asclepiadea. 725 



granules were not often to be found even in the tube, especially 

 after it had acquired considerable length*. 



Almost every grain in the mass had produced its tube, and 

 the tubes were directed from all parts of it towards the point of 

 dehiscence. In this state the mass had become more convex 

 from the increased bulk of its contents. 



The tube so produced from each grain of pollen cannot be said 

 to be emitted from it, but is manifestly an elongation of its mem- 

 brane. These tubes are transparent, cylindrical, about l-2000th 

 of an inch in diameter, neither branched nor jointed, with no 

 apparent interruption in their cavity, and when of great length, 

 which they often attain, are frequently without granular matter. 



I next proceeded to examine the course of the cord, which in 

 most cases, — and indeed in all where the mass had remained a 

 sufficient length of time in the fissure, — had opened a passage 

 for itself through the membrane, or rather had separated the 

 upper edge of this membrane from the base of the stigma, to 

 which it was before united. Having effected this separation, 

 it was found to proceed along the surface of the base of the 

 stigma in a line exactly opposite to the glands seated on the 

 apex of the same bevelled angle. The cord having passed 

 along the surface of the attenuated base of the stigma until 

 it arrives at its articulation with the two styles, then inclines 

 towards the inner side of the apex of the style nearest to it, and 

 actually introduces itself, wholly or in part, into the hollow of 

 the apex, which in this stage is in some degree exposedt. But 

 as the partial separation of the styles from the stigma, then 

 taking place, is not always sufficient for the free admission of 

 the vvhole cord, a few of the tubes not unfrequently become 

 bent, in some cases even zigzag, doubtless in consequence of 



* Tab. 35. fig. 7, & 10 ; and Tab. 34. %. 12. 

 t Tab. 34. fig. 7—9 ; and Tab. 35. fig. 4, & 10. 



the 



