FUNGI. 



25 



4. INVERTED HYMENIUM. 



Amongst the most interesting and striking of fungal 

 abnormalities is the occurrence, in the higher forms 

 here dealt with, of the fertile tissue, or hymenium, on 

 the upper as well as on the lower surface of the cap. 

 Its common occurrence and striking appearance are 

 both reasons for attempting an adequate explanation 

 thereof. This will be done when the facts have been 

 cited. 



There are two chief forms which this phenomenon 

 assumes. Either (1) the hymenium may uniformly, or 

 in patches, cover the upper surface of the cap, and 

 consist of a foveolar instead of a gill-structure, giving 

 a morchelloid aspect to the whole fruit, or (2) one or 

 more secondary inverted caps may occur on the upper 

 surface. 



Superior Hymenium. — The writer has seen an in- 

 stance of this in Tubaria furfuracea. In this case, 

 however, the hymenial tissues were very irregular, 

 constituting a transitional structure between the 

 foveolate and the gill-type (PI. II, figs. 11 and 12). 

 In Mycdena luteo-alba he has seen a much more typical 

 foveolate hymenium which was continuous, by means 

 of an invagination on one side, with the normal gill- 

 hymenium below. W. Gr. Smith figures forms of 

 Agaricus furfurascens which were exactly like morels, 

 and moreover all transitions occurred between them 

 and the normal forms amongst which they grew. 



Boudier describes a Gortinarius, the surface of whose 

 cap was beset with broad, irregular pores or sma n 

 alveolae, 2-4 mm. in diameter and 5 mm. deep, and 

 undulating walls covered with spores. The inter- 

 lamellar spaces on the lower side of the cap were 

 continuous over the margin with the alveolae above. 



Dumee and Lutz describe a similar Cortinarius, but 

 in their case the hymenium only covered a quarter of 

 the cap's surface. 



Montague, in Gay's ' Flora of Chile,' cites " Stylo- 



