iQiQj U ALKER—PLUTEUS AND TUBARIA 17 



TUBARIA FURFURACEA 



1. The primordium of the basidiocarp consists of loosely inter- 

 woven hyphae of uniform size. 



2. The development of the fruit body is endogenous. The 

 primordium of the stipe as a conical region of small deeply staining 

 filaments is the first to be differentiated. . The primordium of the 

 pileus originates as an outgrowth of the apical end of the elongat- 

 ing stipe. A well defined blematogen, consisting of the undiffer- 

 entiated ground tissue, surrounds the entire young fruit body. 



3. The primordium of the hymenophore appears soon after the 

 differentiation of the primordium of the pileus. At first it is only 

 distinguishable by its deeper staining properties, but soon the 

 filaments in the region come to lie parallel to each other and form 

 a definite level palisade layer. 



4. The development of the primordium of the hymenophore is 

 accompanied by a stretching apart of the filaments below it to form 

 a definite but weak annular prelamellar cavity. 



5. The gills originate as radial folds in a previously uniform 

 palisade layer. Their development is centrifugal and they very 

 often branch toward the margin. 



6. The secondary gills develop similarly but at varying dis- 

 tances from the stipe. 



7. The surface of the pileus is never clearly defined, but at all 

 times merges gradually into that of the blematogen. The cells 

 of the blematogen become inflated and easily separate from each 

 other. For this reason it is easily destroyed. 



8. The marginal or partial veil is made up of 2 layers. The 

 outer consists of blematogen, while the inner is made up largely of 

 fi.laments that are continuations of those making up the margin 

 of the pileus. and which are also attached to the stipe. The veil 

 ruptures irregularly at maturity and is so delicate that it soon 

 disappears. 



In conclusion. I wish to express my deep obligation to the late 



Professor George F. Atkinson for the use of his laboratories 



during the summers of 19 16 and 191 7, for his constant interest in 



my work, and for his many helpful suggestions. 



University of Nebraska 

 Lincoln, Neb. 



