534 MINNESOTA BOTANICAL STUDIES. 



placed in the genus Dictyophora on account of its having a 

 persistent membrane hanging about the angle between the pileus 

 and the stipe. This membrane is composed of the same tissue, 

 the intermediate tissue A of my figures ; which gives rise to the 

 veil in D. duplicata. Differentiation of this tissue does not 

 advance in D. ravenelii to the final stage of making this mem- 

 brane pseudoparenchyma, or is this final stage reached in the 

 case of hyphas composing the pileus in /. impudtcus and in D. 

 duplicata, yet no one would hesitate on that ground to use the 

 term pileus in connection with those species. It seems best to 

 apply the term veil to this membrane in D. ravenelii which 

 looks like a veil, has the position of a veil, is composed of a 

 tissue forming the veil in other species and is likely to be re- 

 garded as a veil without question by every botanist meeting this 

 fungus for the first time and attempting its determination." 



Burt's interpretation of this structure seems hardly the best 

 one. The membrane as shown in detail in Fig. 15 bears no 

 resemblance whatever to the tissue of the stipe and pileus shown 

 in detail with the same enlargement in Figs. 14 and 16. The 

 attachment of this membrane at the base of the volva and the 

 fact that it ruptures irregularly, are both strong reasons for not 

 considering it as a true veil or indusium. It would seem better 

 to regard it rather as tissue which in other species of both 

 Itkyphallus and Dictyophora, is completely disorganized with 

 the exception possibly of /. tennis, mentioned by Penzig, where 

 also a similar structure occurs. The presence of this tissue, al- 

 though noted by the earlier writers, was not considered of im- 

 portance enough to exclude the plant from the genus in which 

 its other characteristics certainly placed it. 



The pileus is composed of tissue very similar in structure to 

 that of the stipe, except that the walls are closely folded and 

 the tissue of the chambers is not so completely disorganized. 

 The structure of one of the folds is shown in Fig. 14 while a 

 longitudinal section showing the relative position of the walls is 

 shown in Fig. 18. From a surface view the pileus has a finely 

 wrinkled or granulated appearance. It is firmly attached to the 

 apex of the stipe just below the collar. The line of demarka- 

 tion between the pileus and the stipe at the point of attachment 

 is not easy to make out. In fact at the point of union the tissue 

 of the three areas, stipe, pileus and collar is homogeneous. It 

 is close within the axis of the stipe and pileus that the so-called 



