ORDER PEZIZALES 



225 



Fig. 75. Pezizales, Family Pezizaceae. (A, B) Ascobolus carbonarius Karst. (A) 

 Ascogonium with trichogyne reaching out to a distant antherid. (B) Ascogenous 

 hyphae beginning to bud out from ascogonial cells. (C) Ascobolus magnijicus Dodge, 

 ascogonium coiling around antherid. (A-B, after Dodge: Bull. Torrey Botan. Club, 

 39(4):139-197. C, after Dodge, Mycologia, 12(3):115-134.) 



and the Inoperculatae. In the former a little lid (operculum) is formed at 

 the apex of each ascus. This gives way when the turgor pressure reaches 

 a certain degree, thus allowing the escape of the ascospores and the sur- 

 rounding liquid. The operculum may be shot off entirely but more often 

 remains attached at one edge like a trap door. A modification of the 

 typical operculate type is apparently the bilabiate type. In the Inoper- 

 culatae the thickened apex of the ascus gradually softens and suddenly 

 yields to the internal pressure forming a pore through Avhich the ascus 

 contents escape. 



In the Pezizales the ascospores are one-celled and ellipsoidal to sub- 

 spherical to a much greater extent than in the Lecanorales where many- 

 celled ascospores are common. The apothecia in this order vary greatly 

 in size. In a few species of Ascobolus and some other genera the apo- 

 thecium is less than a millimeter in diameter; in the larger number of 

 genera and species it is from 5 to 20 mm. in diameter. As mentioned in 

 the preceding chapter a specimen of Geopyxis cacahus (Fr.) Sacc. was 

 collected in Java that was nearly a meter high and about 50 cm. across. 

 Seaver (1942) reported that Dr. Helen M. Gilkey and Dr. S. M. Zeller 

 found a specimen of Daleomyces phillipsii (Massee) Seaver in Oregon 

 that had a diameter of 40 in. (about 1 meter). The shape is also subject 

 to great variation. In Pyronema and some other genera it is convex and 

 naked from the beginning. In more forms it is flat or cup-shaped and in 

 most of them the hymenial surface is at first covered with a more or less 

 evanescent layer. Some species have a subspherical apothecium, at first 

 closed and then opening at the apex by an enlarging pore or ostiole. The 

 apothecium is more often sessile but yet is stalked in many genera. A few 

 genera produce their apothecia just under the surface of the soil, opening 

 by a small pore at the surface when the apothecium is mature. In Cyttaria, 



