95 



This is also shown by the fact that quite generally all the plants 

 on a single stump, both large and small, will come to maturity 

 at the same time. 



As we have noticed before, Polyporiis lucidiis is one of the 

 stalked Polypori, but the length of the stalk is variable with the 

 different plants, some being nearly sessile, while others have 

 very long stalks. The stalk is the first part of the plant to de- 

 velop. From the button stage, the plant continues to add on 

 more tissue exogenously, all of which becomes covered with the 

 red varnish except about one to two centimeters of the terminal 

 margin, which remains white. However, after the plant has 

 been growing for seven to fifteen days, it will be noticed that the 

 white part on the under side of the plant is becoming longer. It 

 does not become varnished over as fast as it is formed. Or, in 

 other words, the pileus has commenced to form. This is rather 

 a slow process at first, as the cap does not seem to be started all 

 at once, but the varnishing process on the under side gradually 

 slackens up. Consequently as the plant develops, there is left a 

 greater white area beneath. This white area is used in the curve 

 representing the development of the pileus. This area does not 

 all develop into pileus, for that of the first few days of develop- 

 ment becomes part of the stalk. It is impossible to tell how 

 much of this white area will be stalk and how much pileus until 

 several days after it begms to increase in size. Then the bound- 

 aries of the cap or the hymenial surface become marked out, and 

 consequently thereafter, the increase of the cap equals that of the 

 whole plant. The formation of the pileus does not begin at the 

 same time with all plants, so it is a difficult matter to show its 

 development with a curve. But this was attempted by selecting 

 a number of plants having about the same length of stalk, about 

 six centimeters, and plotting the average increase of the white 

 area on the under side of the pileus. This show^s that in plants 

 with stalks of this size, the stalk reaches its complete develop- 

 ment between the twelfth and eighteenth days, and also that the 

 boundary of the cap is established between these dates. Of 

 course with a longer or shorter stalk this would vary somewhat. 

 But the curve shows the most important fact, that the formation 

 of the pileus is a gradual process. 



