1916] Gilkcy: A Revision of the Tuhcralcs of California 319 



of the spore surface of T. dnjophilum are said to measure 14 by 21ju,, 

 while those of T. argentenm are generally G-Sfx. The former is also re- 

 corded as having occasional more minutely alveolate spores occurring 

 with those of coarser alveoli, but in the Californian species the num- 

 ber and size of alveoli varv little. 



Tuber (Eutuber) australe Speg. ( ?) 



Plate 30, fig. 29 



Spegazzini, Auii. de Soc. Cien. Argentina, vol. 24 (1887), p. 122. 

 Harkness, Proc. Cal. Acad. Sci., 3d ser., vol. 1. no. 8 (1899), p. 272. 



Aseocarp reddish brown (preserved), 1cm. in diam., nearly glo- 

 bose, very even with few wrinkles, minutely verrucosc ; gleba yellow 

 gray, of loose texture ; veins not conspicuous in cut surface ; pseudo- 

 parenchymatous layer of cortex thin, changing soon to compact tissue 

 of coalescent hyphae of subcortex ; thickness of pei'idium 480/x ; venae 

 internae and tissue separating asci of similar structure to subcortex, 

 with hyphae somewhat less closely united ; venae externae of loosely 

 interwoven branched hyphae 5-6/x, thick ; asci more or less pyriform, 

 48-60 by 60-80/x, 1-2-spored ; spores greenish yellow, nearly globose, 

 30-40 by 32-48/i., alveolate 7-11 by 8-12 alveoli across diameters. 



"Among oaks in vegetable humus upon a well-drained hillside, Au- 

 burn, Placer Co., Calif., June." No. 203, Hk. Col. 



It is difficult to decide whether or not this species is identical witli 

 Tuher australe, for descriptions of the latter species are meagre, and 

 no illustration of it exists, so far as I have been able to determine. 

 Also, only one specimen of the Harkness material is ])resent in the 

 collection, and Harkness made no critical notes upon this species. 

 Which characters are variable in different plants, therefore, and which 

 are modified by the preserving alcohol must remain in doubt. IIo^\'- 

 ever, most characters of the alcoholic specimen agree in general with 

 the descriptions of T. australe, the color of the aseocarp being the 

 only serious point of disagreement. This, however, has probably 

 changed since the specimen was preserved. The surface of the Hark- 

 ness plant is also slightly verrueose rather than smooth as described 

 for T. australe, l)ut tliis amount of variation sometimes occurs in dif- 

 ferent plants of a s])ecies. It seems best, therefore, to leave this speci- 

 men under 7\ australe until more material may be available for study. 



