310 University of California Puhlications in Botany [Vol.6 



fornian species that have been collected have alveolate spores; and of 

 these species all but one must be included under Eututcr. No speci- 

 mens of true Sphaerogaster have yet been reported, though T. lig- 

 narium comes very near. Tlie same relationship evidently exists in 

 Europe between globose and ellipsoid-spored species, the latter being 

 far in the majority. 



In the descriptions which follow, aside from the size, shape and 

 surface characters of the ascocarp and spore, there have been con- 

 sidered the thickness of the peridium and the structure of the venae 

 internae and the tissue lying between the asci. The two latter tissues 

 originate from the subcortex and are generally similar in character ; 

 but occasional cases are found in which one has become modified with- 

 out a corresponding modification of the others. The structure and 

 arrangement of these three tissues are not always constant in a species, 

 but generally they are little variable. In a number of eases these 

 tissues are composed of long-celled hyphae, more or less regularly ar- 

 ranged, which have coalesced, forming practically a pseudoparen- 

 chymatous layer of somewhat elongated cells of various sizes. Some- 

 times, also, apparently true pseudoparenchyma exists in such tissues, 

 the latter appearing in section as an even layer of equal, united, globu- 

 lar cells. Whether this is really pseudoparenchyma, or whether the 

 effect is produced by a section across the long diameters of the united 

 hyphae previously described has not yet been determined. An illus- 

 tration of these two tissues wall be found in the figure of T. candidum, 

 plate 27. 



EuTUBER. Spores alveolate, ellipsoid. 



A. Surface of ascocarp smooth. 



a. Ascocarp lobed or convolute. 



Ascocarp reaching 2 cm. in diam., yellow; asci 1-4-spored; si)ores 26- 

 -36 by 30-44^; 7 by 8 alveoli across diameters T. citrimim. 



Ascocarp reaching 1.5 cm., dirty white, lobed and wrinkled; asci 2-4- 

 spored; spores round-ellipsoid, 28-34 by 32-40^; 11-14 by 12-16 



alveoli across diameters T. monticolum. 



h. Ascocarp even. 



Ascocarp reaching 2 cm., clay -brown; asci 1-4-spored; spores round- 

 ellipsoid, 32-48 by 36-52^^; 3-10 by 4-13 alveoli across diameters.. 

 T. levisftimum. 



B. Surface of ascocarp verrueose, scabrous, or minutely wrinkled. 

 a. Ascocarp lobed or convolute. 



Ascocarp reaching 1.5 cm., cinnamon-brown, minutely scabrous; spores 

 long-ellipsoid, pointed at both ends, 28-38 by 36-52/x; 6 by 7 alveoli 

 across diameters T. gibbosum. 



