HYPOCREALES 



243 



growth continues at the base, forming new perithecia in the new growth 

 zones. Thus the fructifications may attain a cross section of several 

 centimeters. 



The species of Hypocrella are also epiphytic or ectoparasitic on stems 

 and leaves. The Brazilian H. cavernosa corresponds in the essentials of 

 its form to Konradia bambusina. On Merostachys speciosa, it forms 

 spherical stromata on which Fusarium conidia are cut off in depressions 

 and labyrinthine cavities and later form perithecia. In the Brazilian H. 

 verruculosa, on bamboo, the surface of the stroma begins to be differenti- 

 ated in a characteristic manner. After a time, the stroma grows on a 

 limited circular spot which develops a reticulate system of channels. In 

 the Brazilian H. Gaertneriana, on bamboo, these protrusions develop to 

 verrucose protuberances on which alone the perithecia are formed (Fig. 



Fig. 158. — Hypocrclla Gaertneriana on bam- 

 boo. (Natural size; after Moller, 1901.) 



Fig. 159. — Mycomalus bambusinus on bam- 

 boo. (Natural size; after Moller, 1901.) 



158). In this species the surface of the stroma, for the first time in the 

 Scolecosporae (as in Xylocrea of the Amerosporae) is differentiated into 

 a fertile and a sterile part. 



This division of the surface of the fructification into fertile and sterile 

 zones extends still further in the following genera on bamboo, in a charac- 

 teristic manner on each : in Mycomalus leading to the formation of a single 

 equatorial fertile ring and in Ascopolyporus to dorsiventral brackets. 

 In Brazil on dead twigs of Guadua taguara (even on those 2 mm. in diam- 

 eter), Mycomalus bambusinus forms chestnut brown, apple-shaped balls 

 up to 5 cm. in size, around which extends the pulvinate, melleous, fertile 

 zone as a broad girdle arching over above and below (Fig. 159). Its 

 perithecia are very far apart, only about 9 per square centimeter. 



In Ascopolyporus, differentiation is more horizontal. In the lower 

 forms, as A. polychrous and A. villosus, the fructifications are still spheri- 

 cal; in the latter, however, the upper side of the sphere is distinguished 

 from the lower by a tomentum visible to the naked eye. In the highest 

 known member of the genus, A. polyporoides, the fructifications are flat- 



