12 



STUDIES OF AMERICAN FUNGI. 



they dangle downward in exquisite fashion. The mycelium in this 

 condition is very soft and perishable. It disappears almost at touch. 

 On the posts or wood props used to support the rock roof above, 

 the mycelium grows in great profusion also, often covering them 

 with a thick white mantle, or draping them with a fabric of elegant 

 texture. From the upper ends of the props it spreads out over the 

 rock roof above for several feet in circumference, and beautiful white 

 pendulous tassels remind one of stalactites. 



Direction in Growth of Mushrooms. The direction of growth which 

 these fungi take forms an interesting question for study. The com- 

 mon mushroom, the 

 Agaricus, the amani- 

 tas, and other central 

 stemmed species grow 

 usually in an upright 

 fashion ; that is, the 

 stem is erect. The 

 cap then, when it ex- 

 pands, stands so that 

 it is parallel with the 

 surface of the earth. 

 Where the cap does 

 not fully expand, as 

 in the campanulate 

 forms, the pileus is 

 still oriented horizon- 

 tally, that is, with the 

 gills downward. Even 

 in such species, where 

 the stems are ascend- 

 ing, the upper end of 

 the stem curves so 



FIGURE 12. Agaricus campestris. Spore print. (Natural size.) 



that the cap occupies the usual position with reference to the surface 

 of the earth. This is beautifully shown in the case of those plants 

 which grow on the side of trunks or stumps, where the stems could 

 not well grow directly upward without hugging close to the side of 

 the trunk, and then there would not be room for the expansion of 

 the cap. This is well shown in a number of species of Mycena. 



In those species where the stem is subcentral, i. e., set toward 

 one side of the pileus, or where it is definitely lateral, the pileus is 

 also expanded in a horizontal direction. From these lateral stemmed 

 species there is an easy transition to the stemless forms which are 



