Chap. m. LINUM GEANDIFLORUM. 89 



short-styled flower were penetrated by innumerable 

 tubes, which were as yet short, and the stigmas them- 

 selves were not at all discoloured. The three stigmas 

 covered with their own-form pollen were not pene- 

 trated 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 

 penetrated 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. 



Tenthly. 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 one 

 stigma, which was deeply penetrated by a multitude 

 of tubes from the short-styled pollen, presented a 

 conspicuous difi'erence 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 



