1909] CURRENT LITERATURE 77 



by Dr. W. A. Setchell and Dr. N. L. Gardner in the region of Berkeley, Califor- 

 nia, during the years 1903-1905. It is of especial interest and importance in 

 view of the fact that so little attention has been given heretofore to the collection 

 of subterranean fungi in North America, and because this new material, some 

 of it in young stages, has enabled the author to put some of the imperfectly 

 described genera of Harkness on a better footing, and to revise some of his 

 own opinions as to the systematic position of certain genera which have occupied 

 an unsatisfactory position. 



Some of the more important results are as follows : Myrmecocystis cerebriformis 

 Harkness and M. Candida Harkness are shown to be identical, the former being 

 an older and mature stage, while the latter is unripe material of the same species. 

 The former name has precedence. Myrmecocystis Harkness (1899) is also shown 

 to be generically identical with Pseudogenea vallisumbrosae Bucholtz (1900), and 

 the latter becomes M. vallisumbrosae (Bucholtz) E. Fischer. Young material 

 of Piersonia, a genus imperfectly described by Harkness from old material, 

 shows that this is a very interesting genus. The small nests of asci in the interior 

 of the fruit body are arranged in separate, pouchlike segments of hymenia, with 

 the free ends of the asci facing open passages or chambers terminating the venae 

 externae, the point of junction being rather abruptly narrowed. Paraphyses are 

 irregularly distributed among the asci in groups or partly wanting, but line the 

 surface of the venae externae. The latter in the deeper parts of the fruit body 

 are filled with a loose weft of hyaline hyphae developed from the ends of certain 

 the paraphyses; while toward the external portion of the fruit body brown 



hyph 



ae are intermingled and become more abundant as the openings of the 



Venae exte mae are reached. In the arrangement and form of the asci Piersonia 

 resembles Pachyphloeus, the absence of hyphae in the hymenia-lined passages 

 recalls Hydnotrya; but the most characteristic feature in which Piersonia differs 

 rom other genera is the sharply localized condition of the hymenial parts, since 

 r \ ° EutuDe rineae the venae externae are lined throughout by the hymenium. 

 is respect Piersonia represents a special type at one extreme of an arm in the 



nes Eutuberineae, in which the ascus hymenium has disappeared from a large 

 po ion of the venae externae and is found only at the innermost terminations of 



e m olding of the same. Fischer suggests that Piersonia may give the clue 

 e proper interpretation of the structure of Choiromyces which he has formerly 



ace with the Plectascineae, where it certainly occupies a rather anomalous 

 pouchH* 1 * US distinct h y m enium. His suggestion now is that the large, irregular 

 smaller hymenial Potions in the fruit body of Choiromyces may, like the 

 in Choi ° nCS ° f Piersonia ' stand at the terminations of the venae externae, which 

 their ° lr ° myc ^ s have become completely and evenly filled, and all evidence of 

 merd^T 1111110 ^ 011 with the outside ma >' have thus disappeared. Fischer 

 young m eK thiS ** a su §g estion - It; wW require developmental studies of 



tion, i t w^ih aI t0 deCide the V ™*' Should this P rove t0 ** the true inter P reta " 



the PleT 11 1Cnd S ° me su PP° rt to Mattirolo's view that the difference between 



eC ascales and Tuberales is not fundamentally sufficient to warrant their 



