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IX. On the Pollen of- Flowers, By Mrs. Agnes Ibbetson. 



To Dr. Tilloch. 



Sir, — IVIy last gave the most convincing proof that there 

 is no such thing as perspiration in plants, and that the water 

 found under a glass when a vegetable is placed within it (with- 

 out earth) is nothing more than the condensation of the atmo- 

 sphere, shown and exemplified by the sky-light, and the water 

 that runs on the stairs; and there being scarce a drop of 

 moisture in the interior vessel when the plant is covered witli 

 two glasses, though the exterior cylinder is inundated as usual. 



I now turn to my next subject, which will give the whole 

 history of the pollen from the moment it is first protruded in 

 the plant to the time it completes its fi'uctification of the seed. 

 The pollen is always formed in the tap root (PL I. fig. 1, «c) : 

 the anthers and filaments are a mere late production, and are 

 never discovered m the plant till the bud forms them while com- 

 pleting other parts at the top of the plant : the pollen is there- 

 fore foi'med in the root perfectly uncovered (PI. I. fig. 1, aca): 

 if the tap root is eradicated, the pollen forms just above the 

 cut; but is rarely in trees found in the side roots, except in 

 Jirs. It passes up in all trees but in the Dioecious order, where, 

 being separated entirely from the female, it runs up the pith 

 or interior wood of the stem, in the male plant perfectly naked, 

 fig. 11, m. When the anthers begin to form in the male 

 bud, in dioecious trees, nothing can be more evident than the 

 entering of the pollen into them, fig. 2. They are then so 

 stuffed and filled to bursting as to form a curious moving spe- 

 cimen for many minutes alter being placed under the glass. 

 It is then that the filaments are formed and shoot forth from 

 the male bud, that they may carry the anthers and pollen into the 

 air, where they generally swing for some hours, if not days. 

 There is every reason to believe that they thus procure a 

 quantity of gas, absorbing it by the help of their motion : thus 

 they soon become ripe ; and when the pistil has displayed those 

 indications of being rcady to complete the seed, by the swell- 

 ing of the bubble of liquid at the summit, the pollen again 

 leaves the anthers and flies to that nectarious drop, which at- 

 tracts it to the pistil, and remains fastened by the hairs to which 

 the balls adhere, and are in a short time dissolved by the 

 juices of the pistil, down which it runs in various gutters till 

 it has reached the seeds, which it enters mixed with the nec- 

 tarious juice, and thus fructifies them. 



When the pollen passes up in Dioecious trees, it forms a 

 curious specimen: the balls of the pollen are generally large 



and 



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