286 University of California PuMications in Botany [Vol. 6 



an almost simple ascocarp and one having the cavity dissected into 

 complex canals with the walls more or less coalesced to form closed 

 chambers. G. magniflca represented the highest development in this 

 genus of the latter condition ; and occasional openings, apparently due 

 to growth, Avere found in both species. (2) The very close similarity 

 of form and structure between Balsamia and Pseudohalsamia, de- 

 scribed under the latter genus, seems to indicate a nearer relationship 

 than that attributed to them by Fischer. (3) Fascicled paraphyses 

 and occasional undeveloped asci in the sterile canals of Piersonia de- 

 note the possible disappearance, mentioned above, of asci from these 

 parts, and the resultant closing together to form the very narrow 

 channels leading to the hymenial areas. (4) The actual condition 

 was found in young ascocarps of Tuber candidum in which folds of 

 tissue of varying size and shape from the subcortex were projected 

 into the cavity and became fitted so closely together that all trace of 

 the original folds as such was lost. The walls were covered with a 

 hymenial palisade of asci and paraphyses, which was perfectly regular 

 except for a rare ascus which had apparently been too crowded in de- 

 velopment and had not been able to parallel in position the other asci. 

 At first the whole cavity of the ascocarp was apparently in communi- 

 cation, but as the various folds and projections of irregular form be- 

 came fitted together, many of the paraphyses developed into the 

 canals, filling them with tangled hyphae which became more or less 

 compressed, and the original system was finally hidden in the mass of 

 tissue, asci, and spores. The wider canals did not lose their identity 

 but remained as venae externae. The venae internae in this case were 

 clearly the original folds or projections, and not simply compressed 

 layers of tissue taking the form of veins between developing asci, as 

 they have generally been understood in other species. 



The material was not sufficiently young to show the complete de- 

 velopment of the external openings, but so far as observed the asco- 

 carp did not appear to have the gymnocarpous origin which Bucholtz 

 (1903, pp. 154-158) believed he had discovered for Tuber. Further 

 studies of young ascocarps, however, are expected to throw more light 

 upon this point. 



