1916] (iilkcij: A Revision of the TiihrraJrs of California 325 



This species diffei's from T. candidum principally in completely 

 smooth surface, fewer venae externae, these mnch enlarged in places 

 and becoming open, and in the globose or neai'ly globose spores with 

 somewhat curved spines. There are other less tangible characters 

 which are difficult to describe but which tend distinctly to separate 

 the two species. The color of tlie ascocarp in llie alcoholic specimen 

 of T. lignaria is shining bluish black, with white gleba ; while in all 

 alcoholic material of T. vandiditni, both in the Harkness and Univer- 

 sity of California herbaria, the ascocarp surface is somewhat reddish 

 brown with lighter brown gleba. 



T. lignariuin apparently does not come near any described form, 

 its spore shape and character together with the smooth surface of the 

 ascocarp and the few venae externae distinguishing it. Very few 

 Sphaerogasters have been described, and most of these are apparently 

 little known (Paoletti, 1889, p. 885) ; of described Oogasters, none 

 w^ere found with measurements cited as nearly globose as those of T. 

 Ugnarium. 



Piersonia Ilk. 



Ascocarp subglobose ; gleba with wide or narrow strands of sterile 

 tissue separating irregular chambers lined with hymenium, latter 

 sometimes appearing as colored dots on cut surface, connected with 

 exterior by narrow venae externae ; latter short or forming long canals 

 through gleba, lined with more or less conspicuous paraphyses, some 

 developing into branched tangled hyphae filling veins ; hymenial 

 chambers variously shai)ed by inward projecting branches of inter- 

 hymenial tissue ; asci and paraphyses arranged in more or less regular 

 palisade, crowded, asci often deformed from crowding, generally some- 

 what club-shaped, 1 to 4-spored, some spores often not maturing; 

 paraphyses fascicled between asci, somewhat swollen at tips. 



The genus Piersonia is distinguished from all other genera of the 

 Tuberales in having the asci in chambers which open to the exterior 

 of the ascocarp by long sterile canals. These canals are lined with 

 paraphyses which continue into and throughout the hymenium; and 

 are perhaps approximated or at least foreshadowed in the inward pro- 

 jecting portions of ascocarp surface in Ifi/dnotrini, these sometimes 

 extending for long distances into the gleba where tliey (){)en to the 

 hymenium, the swollen-tipped hyphae of the surface showing gradual 

 transition into paraphyses. However, the fascicled paraphyses in the 

 venae externae of Piersonia hispora, witli the presence of occasional 

 undeveloped asci, would indicate the possible oi-igin of the sterile 



