318 



COMPARATIVE MORPHOLOGY OF FUNGI 



separated from each other by irregular paraphysoid hyphae intertwined 

 above to a loose, lumpy epithecium (probably the remains of an inter- 

 thecial stroma) as imperfect stages, free conidiophores, and pycnia 



are known. 



In the higher groups, as the Dermateaceae (apothecia horny or 

 leathery) and Bulgariaceae (apothecia gelatinous), the fructifications 

 are conspicuous and possess a typical apothecial structure. Their disc 

 is covered by a membranous layer which is finally torn and disappears; 

 by this character they are related to the Phacidiales, on one hand to the 

 Stictidaceae whose fructifications, as in the Bulgariaceae, are gelatinous, 

 and on the other hand to the Tryblidiaceae which usually seem decep- 

 tively like many Dermateaceae, e.g., certain species of Cenangium. The 



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Fig. 209. — Dermatea Ccrasi. 1. Section of stroma, with apothecia, a; conidial cavities, 

 c. 2. Macro- and microconidia. Dermatea carpinea. 3. Stroma showing apothecia, a; 

 conidial fructification, c. 4. Portion of conidial fructification of Dermatella dissepta, showing 

 bacilliform conidia, s; ellipsoidal conidia, r. (1 X 10; 2, 4 X 380; after Tulasne.) 



paraphyses intertwine to a firm epithecium above the tips of the asci 

 in the Bulgariaceae and Dermateaceae (as in many Philipsiellaceae- 

 Patellariaceae and Phacidiales). 



Dermateaceae. — Some species of Dermatea and Cenangium are 

 important plant pathogens. Their several fructifications are erumpent 

 from a poorly developed hypophloedal stroma ("Fig. 209 ( ) ; when dry, they 

 form an invisible, usually dark-colored membrane; in moist weather they 

 swell to conspicuous leathery structures. The same stroma bears first 

 conidia, later apothecia. In many forms, as D. Cerasi, the conidiophores 

 are united into Valsaceous pycnia (Fig. 209, 1), in others as Dermatella 

 dissepta they are free on the substrate (Fig. 209, 4). Dermatea carpinea 

 causes a dangerous stem and twig disease of the hornbeam, D. cinnamomea, 

 a similar one of oak and Cenangium Abietis, one on pines. 



