﻿BOTANICAL GAZETTE 



on May 13, the temperature being 17 0 C, and they were kept in 

 the dark. 1 



May 14, 1913. — The cultures were examined at 12:20 p.m., 

 the temperature being 16? 5 C: (a) very few had germinated; one 

 had a pollen tube 58.5/1 long and another a pollen tube 309 /n long 

 between perpendicular lines ; (b) very few had germinated ; one had 

 a pollen tube 167 /jl long; (c) very few had germinated; one had 

 a pollen tube 150.3 n long; (d) very few had germinated; one 

 had a pollen tube 58.5 p long and another a pollen tube 108.5 M 

 long; (e) no pollen tubes observed; (/) only a few had formed short 

 pollen tubes, which were covered with short knoblike excrescences 

 and did not seem to be healthy. 



May 15, 1913. — The temperature at 4:00 p.m. was 16 0 C; the 

 results of examination were as follows: (a) an extremely small 

 percentage had germinated; (b) no change; the culture was over- 

 run with yeastlike cells of Penicillium; (c) and d) same as (b); 

 (e) two pollen tubes observed; Penicillium plentiful; (/) no change; 

 Penicillium abundant. 



SERIES IV 



May 15, 1913. — A flower of Warner's King apple was pulled 

 this morning. On examination some of the pollen grains showed 

 short pollen tubes which had been formed inside the anther. 

 Five cultures of the pollen grains were made, namely, (a) in water, 



(b) 2 . 5, (c) 5, (d) 10, and (e) 15 per cent sugar solution respectively. 

 They were put into an incubator at 22.5-23 0 C. at 10:40 a.m. the 

 same day and examined at 4:35 p.m. The results were as follows: 

 (a) most of the pollen grains had formed long pollen tubes; one 

 measured 451 m and another 384 n, and these were about the 

 average lengths; (b) almost every pollen grain had produced a 

 long tube; the average length of the pollen tubes was 634. 6 /x; 



(c) only a few had germinated and the pollen tubes were of short, 

 irregular, tuberculate growth; (d) only a few had formed pollen 

 tubes of irregular growth; (e) two or three pollen grains had formed 

 very short pollen tubes of irregular growth. 



1 In measuring the length of pollen tubes in this and subsequent series, as the 



