HELVELLEAE. 455 



Rhizina myrothectoides. Mass. 



Gregarious, suborbicular, almost or quite plane, rather 

 thin, cartilaginous when dry, disc blackish-green, margin 

 more or less torn, tomontose, yellowish, up to 1 cm. across ; 

 cortical cells large, polygonal; asci cylindrical, 8-spored; 

 spores hyaline, continuous, elliptic-oblong, 1 2-guttulate, 

 wall smooth, thick, 18-20 x 10-12 p.; obliquely 1 -seriate ; 

 paraphy.ses septate, tips clavate and brownish, longer than 

 the asci. 



Psilopezia myrothecioides, B. & Br., Ann. Nat. Hist., n. 1489, 

 t. 11, fig. 5; Phil., Brit. Disc., p. Ill; Sacc., SylL, viii. n. 

 617. 



On wood of Prunus padus and Ulex Europaea. 



Very closely allied to R. Babingtonii ; distinguished chiefly 

 by the dark green disc, and yellowish, fimbriate margin. 



Type specimen examined. 



Rhizina Babingtonii. Mass. 



Expanded from the first, slightly convex, rugulose, 

 glabrous, greyish brown, subcircular or irregular in outline, 

 rather fleshy, shrinking and becoming thin and cartilaginous 

 when dry ; under surface slightly concave, downy or fibril- 

 lose, 12 cm. across ; cortical cells large, irregularly hexa- 

 gonal ; asci cylindrical, 8-spored ; spores hyaline, continuous, 

 elliptic-oblong, ends obtuse, 16-18 X 8-9 p., obliquely 1- 

 iseriate, 1 2-guttulate ; paraphyses slender, septate, clavate 

 and brownish at the tips, longer than the asci. 



Peziza Babingtonii, Berk. & Br., Ann. Nat. Hist., n. 554. 



Psilopezia Babingtonii, Berk., Outl., p. 373; Phil., Brit. 

 Disc., p. 110, pi. v. fig. 23; Sacc., SylL, n. 614. 



On rotten wood. 



When dry the ascophore is very thin and cartilaginous 

 and closely applied to the substratum. 



Type specimen examined. 



HELVELLEAE. 



The principal common feature of the present group is that 

 the disc or hymenium is fully exposed from the earliest stage. 

 There is an absence of the incurved margin of the ascophore 

 when young, and the gradual exposure of the disc so 



