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ATKINSON— MORPHOLOGY AND 



[April 23, 



the salients first appear over this portion of the hymenophore, be- 

 cause it is the older. The older portion of the salients, therefore, 

 extend outward perpendicular to the stem surface. Since their pro- 

 gression is centrifugal, the salients gradually extend over the angle 

 between stem and pileus where their growth is downward. Since 

 the growth in width of the salients is perpendicular to the surface of 

 the level hymenophore at any point, there are formed, in the cases 



12 3 4 5 6 7 8 9 



Diagram 5. Lateral view through one half of a basidiocarp in an in- 

 termediate stage of development, showing (i) the strongly sloping surface 

 of the stem; (2) the partly organized pileus margin which is becoming in 

 volute because of eipnastic growth; (3) the hymenophore presenting three 

 stages of development, (a) the oldest portion, the gill area extending on the 

 under side of the pileus and far down on the surface of the stem (adnate at 

 this stage), (&) the palisade area {PAL) distal to the gill area on under side 

 of pileus, and (c) the primordial area {PR) near margin of pileus; (4) an- 

 nular cavity; (5) the loose ground tissue of the marginal veil; and (6) the 

 blematogen layer. See text. 



under consideration, a series of little stalls, or pigeon holes, around 

 the stem apex, between the young gills in the angle between the stem 



