NORTH AMERICAN ANTHURUS. 



499 



separate its hyphae to a slightly greater extent, and finally stained with aqueous solution 

 of safranin. The hyphae of the chambers will he found quite free from the strands of 

 pseudoparenchyma, while the hyphae of the latter will now be separated sufficiently to 

 show with greater distinctness such conditions of development as have been drawn at 

 x", Fig. 18. 



Final Development. 



Such an intermediate stage of the pseudoparenchyma leads up to its final condition 

 shown in Fig. 10. The walls of the chambers are no longer straight as in Figs. 22 and 

 23, but are thrown into folds closely crowded together (Fig. 10, 



The structure of the wall of the stipe affords the clue to the formation of these 

 folds. The branched and interwoven bundles of medullary hyphae b make the elongation 

 of the chambers dependent upon the elongation of this medullary tissue during its 

 existence. The more rapid growth of the pseudoparenchyma in the chamber walls 

 tends to make these walls longer than the chambers can become during the existence of 

 their medullary contents. The excess in length of the walls is laid down in the folds. 



Elongation of the StijJe. 



When the gleba has attained its maturity and the stipe has completed its folded 

 walls a series of changes occurs in the egg provided external conditions are favorable. 

 Through these changes the elaborately constructed receptaculum bursts from the volva, 

 and rises aloft, conspicuously exposing its spores to the disseminating agency of 

 insects. These changes are: — 



a. The gradual elongation of the egg from its nearly spherical form in early life. 

 During the later stages of this elongation, the volva separates from the receptaculum 

 by the splitting of the inner wall of the peridium (i, Fig. 9) . 



b. The gelatinization and disappearance of the medullary tissue occupying the 

 main central part of the stipe, the chambers of its walls, and the interior of the arms. (The 

 beginning of this change is shown by the main central tissue of the stipe in Fig. 9.) 

 This permits 



c. The straightening out of the folds in the walls of the chambers. 



As a result of these changes, the receptaculum pushes upward against the apex of 

 the peridium, or volva, which becomes thinner there (Fig. 9) and is ruptured finally. 

 The receptaculum then emerges. These changes occur in wet weather. 



The straightening out of the folds in the chamber walls of Phallus caninus and of 

 Phallus impudicus was stated by De Bary to be due, in his opinion, to the inflation of 



