74. ME. DAEAVl:s Olf THE EXISTENCE "Or TWO TOEMS 



coloured and twisted, were straight and fresh-coloxired ; and only 

 one grain had emitted quite a short tube, which could he drawn 

 out of the stigmatic tissue without being ruptured. 

 The following experiments are more striking :— 

 Sixthly. I placed own-form pollen on three of the stigmas of a 

 long-styled flower, and pollen from a short-styled flower on the 

 other two stigmas. After 22 hours these two stigmas were dis- 

 coloured, and slightly twisted, and penetrated by the tubes of 

 numerous pollen-grains : the other three stigmas, covered with 

 their own-form pollen, were fresh, and aU the poUen-graias were 

 loose ; but I did not dissect the whole stigma rigorously. 



SevenMy. Experiment repeated iu the same manner, with the 

 same result. 



Eiffhthly. Experiment repeated, but the stigmas were carefully 

 examined after an iaterval of only 5i hours. The two stigmas with 

 pollen from a short-styled flower were penetrated by innumerable 

 tubes; but these were as yet short, and the stigmas themselves 

 were not at all discoloured. The three stigmas covered with their 

 own-form pollen were not penetrated by a single pollen-tube. 



Ninthly. Put pollen of short-styled on one stigma, and own- 

 form pollen on the other four stigmas ; after 24 hours, found the one 

 stigma somewhat discolotired, and twisted, and penetrated by many 

 long tubes : the other four stigmas were quite straight and fi-esh ; 

 but on dissecting their whole lengths I found that three pollen- 

 grains had protruded quite short tubes into the tissue. 



Tenfhly. Eepeated the experiment, with the same result after 24 

 hours, excepting that only two own-form grains had penetrated the 

 stigmatic tissue with their tubes, to a very short depth ; the one 

 stigma, which was deeply penetrated by a multitude of tubes from 

 the short-styled pollen, presented a conspicuous difference in com- 

 parison with the other four straight and bright pink stigmas, in 

 being much curled, half-shrivelled, and discoloured. 



I could add a few other experiments ; but those now given amply 

 suffice to show that the pollen-grains of a short-styled flower placed 

 on the stigmas of a long-styled flower emit a multitude of tubes 

 after an interval of from five to six houi-s, and penetrate the tissue 

 ultimately to a great depth, and that after twenty-four hours the 

 stigmas thus penetrated change colour, become twisted, and appear 

 half- withered. On the other hand, the pollen-grains of the long- 

 styled flowers placed on their own stigmas, after an interval of a 

 day, or even three days, do not emit their tubes, or at most only 

 three or four grains out of a multitude emit their tubes ; and these 



