1916] Gilkey: A Revision of the Tuherales of California 297 



would place it under Myrmecocystis; but the color of the ascocarp, 

 sculpturing of the spores, and grouping of the asci are intermediate 

 between Myrmecocysiis and Genea. The two genera agree in being 

 verrucose, more or less irregular in form, cavernous with a variously 

 shaped opening at apex, asci and jiaraphyses forming palisade on 

 inner side of wall, with paraphyses extending beyond asci to form 

 secondary cortex. The principal point of difference apparently is in 

 the presence in Gem a of a mycelial tuft at the base, and its absence 

 in Myrmecocystis ; but this difference is noticed among the species in 

 other genera of the Tuberales, e.g., Balsamia (Fischer, 1897a, p. 62). 

 Since the similarity of the two is so marked, and various intermediate 

 forms exist, a separation of the genera not only seems unnecessary but 

 is impossible upon the old basis ; therefore, in order to accommodate 

 the previously mentioned forms, the two genera have been united in 

 this paper. 



Eiigenea subgen. iiov. Spores ellipsoid; asci not ciowded; hymeniuiii rarely in- 

 terrupted by strands of sterile tissue. 

 Spores 28 by 36^, covered by large, irregular (in size and shape) papillae. 



G. compacta. 



Spores 22 by 32;^, minutely and obtusely verrucose G. arcnaria. 



Heterogenea subgen. nov. Spores ellipsoid to nearly globose, asci not crowded; 



hynienium interrupted by strands of sterile tissue. 

 Spores 22 by 28^, covered with papillae varying in size, regularity of outline, 



and number G. Harlcnessii. 



Spores 28 by 32jtt, coarsely papillose, papillae more or less covered by very 



minute papillae G. Gardner ii. 



Myrmecocystis subgen. nov. Spores globose, 28-38(U, papillose or minutely 

 spinose; asci crowded with paraphyses apparently fascicled between; 

 hymenium interrupted by strands of sterile tissue. 



Spores irregularly papillose G. intermedia. 



Spores minutely and densely spinose, spines often coalescing into irregular 

 groups G, cerebriformis. 



Genea compacta Ilk. 

 Plate 30, fig. 32 



Proc. Cal. Acad. Sci., 3d ser., vol. 1, no. 8, 1899, p. 262, plate XLIII, figs. 

 lOa-lO^-. 



Ascocarp liglit brown; 7-1 0cm. in diam., flattened, lobed, surface 

 quite regularly divided into polygons, 5 mm. in diam., forming bases 

 of irregular pointed or truncate pyramidal projections ; outer cells of 

 cortex mostly projecting and pointed, forming superficial layer of 

 short, 1-ceIled hairs with somewhat thickened walls; cavity of asco- 



