282 University of California Puhlications in Botany [Vol.6 



due to growth. Bueholtz makes the statement that ascocarp develop- 

 ment in Genea is wholly unknown (1903, p. 163). Fischer quotes Mat- 

 tirolo as saying that he has examined young material of Balsamia and 

 has concluded that the latter is cleistocarpous in origin (Fischer, 1908, 

 p. 159). I have not yet had an opportunity of consulting the original 

 reference as to the extent of Mattirolo 's study of this genus. 



These observations, with those of De Bary and Solms-Laubach, 

 represent practically all cases, so far as I have been able to discover, 

 of inquiry into the development of the ascomycetous hypogaei. In no 

 case have I found record of observations upon the entire life-history of 

 any species. 



In Engler and Prantl's Die natiirlichen Pfianzenfamilien, Fischer 

 included the ascomycetous hypogaei under two orders — Tuberineae 

 Winter (Tuberales) and Plectascineae Schroter (Plectascales), basing 

 the division upon the presence and absence, respectively, of definite 

 hymenium, and the consequent massing in the latter case of the asci 

 in definite areas. However, the distinction between the two orders, 

 which were considered of different origin but of parallel development, 

 is so obscure that Fischer has since transferred several genera from 

 the Plectascales to the Tuberales, principally upon their resemblance, 

 apparently, to newly-investigated genera which he considers un- 

 doubted Tuberales (Fischer, 1908, p. 160). In the opinion of various 

 botanists the presence or absence of a defined hymenium is not suf- 

 ficient basis for a separation into two orders, and the status of the 

 Plectascales is at present somewhat uncertain. 



The Tuberales in Die natiirlichen Pfianzenfamilien were divided 

 into two families, Eutuberaceae and Balsamiaceae, also considered of 

 different origin but of parallel development. The Eutuberaceae, in- 

 cluding all genera having openings from the hymenium to the exterior 

 of the ascocarp, were placed in phylogenetic line with the gymnocarp- 

 ous Helvellales; while the Balsamiaceae with closed ascocarps were 

 considered descendants of the hemiangiocarpous Pezizales. Under Bal- 

 samiaceae were placed Balsamia, Geopora, and Hydnocystis (the latter 

 two with some doubt) ; and the Eutuberaceae included Genoa, Pseud- 

 hydnotrya, Hydnotrya, Stephensia, PachypJiloeus, and Tuber. In the 

 Botanische Zeitung (1908) Fischer again published an opinion of the 

 relationship of these plants, and his arrangement of the genera at 

 this time, which was largely influenced by investigations of Californian 

 forms, varied in several important points from the original. Pseud- 

 hydnotrya Fischer, which had formerly appeared under Eutuberaceae 



