CHAP. III. LINUM GRANDIFLORUM. 89 



styled flower were penetrated by innumerable tubes, 

 which 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 a short-styled flower on a 

 single long-styled stigma, and own-form pollen on the 

 other four stigmas; after twenty-four hours the one 

 stigma was somewhat discoloured and twisted, and pene- 

 trated by many long tubes: the other four stigmas 

 were quite straight and fresh; but on dissecting them 

 I found that three pollen-grains had protruded very 

 short tubes into the tissue. 



TentUly. Eepeated the experiment, with the same 

 result after twenty-four hours, excepting that only two 

 own-form grains had penetrated the stigmatic tissue 

 with their tubes to a very short depth. The cne stigma, 

 which was deeply penetrated by a multitude of tubes 

 from the short-styled pollen, presented a conspicuous 

 difference in being much curled, half-shrivelled, and 

 discoloured, in comparison with the other four straight 

 and bright pink stigmas. 



I could add other experiments: but those now 

 given amply suffice to show that the pollen-grains of 

 a short-styled flower placed on the stigma of a long- 

 styled flower emit a multitude of tubes after an in- 

 terval of from five to six hours, 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, pollen-grains from a long-styled flower 

 placed on its own stigmas, do not emit their tubes 

 after an interval of a day, or even three days; or at 

 most only three or four grains out of a multitude emit 

 their tubes, and these apparently never penetrate the 



