161 



remaining slightly less than the length. During the last day of 

 the most active stem growth, the width of the pileus made a rapid 

 increase, from 8 to 20 mm. and continued broadening for 32 

 hours, after the stem had ceased to grow, until it reached 40 mm. 

 At the same time the length continued increasing slowly till it 

 reached 25 mm. 



The plant was growing six days and five nights, after its first 

 appearance above the soil. The growth appeared to be no more 

 rapid by night than by day. This was true also of the other 

 specimens measured. In plant A the greatest growth which 

 took place in any one period was during the third day. In the 

 other plants, it occurred sometimes by day and sometimes by 

 night. 



The growth of the other specimens was very similar to this 

 one, which has just been described. Of the records of other 

 young plants, although their measurements were not started as 

 early as in A, several (B, D, F, G, H, I) show an interval of slow 

 growth at first. In records from other plants, which were not 

 completed, because of some injury to the plant, this was also the 

 case. After this short period of slow growth, the stem curves 

 show a period of very rapid growth, lasting from forty to fifty- 

 six hours. In some of the plants (P, B, H, T) the rate was 

 nearly constant throughout the interval. In others (A, E, G, F, 

 I, H) the rate increased up to a certain time and then decreased 

 somev/hat. In a few mushrooms (C, O, T) the curves are quite 

 irregular, showing abrupt changes in succeeding intervals. 



This period of very rapid growth was followed by another 

 interval of slow growth, lasting about twenty-four hours, after 

 which growth ceased. In E, F, G and B the rate was slow and 

 steady for twenty-four hours. In the remaining plants, the curves 

 are irregular showing slow growth at first, followed by a rapid 

 increase in rate. Plant N gained only i mm. during twenty-four 

 hours and 9 mm. during the next eight hours. Growth usually 

 ceased abruptly after this period although in a few cases it con- 

 tinued to increase slightly while the pileus was developing. 



The pileus of all the specimens developed very much as in 

 plant A. In Figure 2, curves of three other plants are given, 



