159 



veil, extending from the margin of the pileus to the stem. As 

 the plant developed, this became free from the stem and clung to 

 the margin of the pileus. When the plant had reached maturity, 

 traces of the veil could still be seen in small V-shaped projections 

 clinging to the pileus, as shown in figures 45, 47 and 48 of Atkin- 

 son's "Mushrooms, edible, poisonous, etc.," 1903. (Figure i.) 



The width of the stem remained nearly the same throughout 

 the growth of the plant. It was slender upon first appearing 

 but it soon increased in diameter, and when the plant was from 

 10 to 20 mm. high, was as large as at maturity. The color of the 

 plant was dark-brown, until the pileus began to expand laterally, 

 when it became grayish and spotted with brown or black patches. 

 It matured in from 80 to 120 hours after appearing above the 

 ground. 



Some of the mushrooms became much larger than others, 

 being at maturity 160 mm. in height, with a pileus of 40 mm. 

 or more in diameter. The majority of the specimens, however, 

 ranged from 120 mm. to 150 mm. in height, with a pileus 30- 

 40 mm. in diameter. Those which became the largest came up 

 nearest the base of the palm or fern trees, due probably to the 

 greater amount of moisture here than towards the edges of the 

 pots. The rate of growth of the eighteen plants, whose records 

 were very nearly complete, has been worked out in curves shown 

 in Figures 2 and 3. 



As No. A was a very typical specimen, and as the most com- 

 plete record was obtained of this, I shall describe its growth in 

 some detail. The first measurements were taken in the morning. 

 During the first 8-hour period by day, the plant did not change. 

 However, during the following night, it began to grow slowly 

 until it was 10 mm. high. On the following day, the stem en- 

 tered on a period of very active growth which lasted about fifty- 

 six hours, until the plant was 145 mm. high. During this 

 period of active growth, the rate at first increased and then de- 

 creased slightly. The stem continued growing slowly for sixteen 

 hours after this rapid growth interval. 



The pileus began to grow slowly at the same time as the stem. 

 It increased steadily but slowly for sixty-four hours, the width 



