PLEUROTUS OSTREATUS 



483 



had probably begun their development about a week before 

 (November 16 ?). Owing to the fact that the tree stood between 

 some wooden palings 

 and a dense Privet 

 hedge, the fruit- 

 bodies were well pro- 

 tected from the wind. 

 On November 23, 

 and again on Novem- 

 ber 25, using my 

 naked eye in diffuse 

 daylight, I was un- 

 able to detect any 

 spore-clouds coming 

 from the fruit-bodies. 

 On December 1, 

 the fruit-bodies were 

 about one-half grown 

 and their upper sur- 

 faces beautifully 

 blue. The day was 

 warm with a 24-hour 

 maximum tempera- 

 ture of 46° F. and a 

 minimum of 40° F.^ 

 At 10.15 in the 

 morning, accom- 



panied by Mrs. J. P. 

 Hillhouse, I visited 

 the tree and, on 



Fig. 



199. — Pleurotus ostreatus on a dying Poplar 

 {Populus serotina). Fruit-bodies grown to about 

 one-third their full size, the pilei with blue upper 

 surfaces and the extending pileus-margins still 

 involute. Spores were seen escaping from these 

 fruit-bodies by day on December 1 and Decem- 

 ber 1,5, and by night (by means of a hand-lamp) 

 from December 15 to December 30. Photographed 

 by J. P. Hillhouse at King's Heath, Birmingham, 

 England, on November 25, 1922. About ^ natural 

 size. 



looking carefully at 

 the edge of the largest fruit-body against the dark background of 

 the palings, distinctly saw spore-clouds passing away at intervals 

 from beneath the pileus ; and Mrs. Hillhouse soon perceived them 

 too. There could be no doubt that, owing to the mild weather, 

 the fruit-body was very actively discharging its spores. Conditions 

 ^ Record of the Midland Institute Observatory, Edgbaston, Birmingham. 



