1916] Gilkey: A Revision of the Tuheralcs of California 323 



however, has the smooth surface of No. 195 with tlie hymenial struc- 

 ture of No. 108. The character of the spore surface ami the shape of 

 the spores differ markedly in a single specimen. The spines in some 

 cases are slender and very numerous and in otlicrs coarser and fewer; 

 while the shape of the spores varies from very glohose-ovoid to long- 

 ovoid. Tn nearly every case, one end of the spore is noticeably pointed 

 and the other rounded. This is particularly conspicuous in sectioned 

 spores, a definite thin spot in the wall at the acute end seeming to be 

 present. No. 425 of the University of California collection has regu- 

 larly longer spores than the other specimens, though in the latter 

 sucli long spores are not uncommon, and No. 425 also has many spores 

 of tlie apparently typical globose-ovoid type. The number of spores 

 in an ascus varies generally from one to four, but in several collec- 

 tions the number is found to reach as high as seven. All the specimens 

 are alike in having one to several undeveloped spores in many of the 

 asci. 



The venae externae distinctly converge, not at one point at the 

 base as in the AscJiion type of the Tubers of Europe, but along the 

 whole line of the furrows of the ascocarp. There may be three or four 

 or more such lines of convergence in one specimen, for there are some- 

 times several separated furrows, occurring on one side or even on 

 opposite sides of the ascocarp. Often, however, only a single, gen- 

 erally branched furrow is present, but this may extend over half the 

 distance around the plant. There is no definite orientation of the 

 ascocarp in the ground in relation to these furrows. 



This species comes very near descriptions of T. rufum (Fischer, 

 1897&. p. 57) in size, color, converging venae externae, sometimes more 

 than four spores in an ascus, several often remaining rudimentary in 

 other asci, spore often pointed at one end, spore and asci measure- 

 ments, and spore sculpturing. The surface of T. rufum is described, 

 however, as early pubescent, becoming glabrous and covered with 

 small, low, polygonal warts oi- areas, separated by rather sharply 

 marked furrows. There is no indication in the young specimens of 

 our plants of definite pubescence, though occasional hairs are found 

 even upon the mature ascocarps. Some, however, as previously noted, 

 show division of the surface into polygonal areas. Tlie consistency 

 of the ascocarp of T. rufum is described as cartilaginous, becoming 

 horny upon drying. Our specimens, particularly those in alcohol, 

 have the consistency of a pickled green olive. The principal differ- 

 ence, however, between T. candidum and 7\ rufum seems to lie in tlie 



