50 MORPHOLOGY, ETC., FUNGI, ETC. [Bot. Absts. 



nudum Bull., are the mushrooms studied. The author considers Bouin's picro-formol 

 the most satisfactory fixing agent and iron haematoxylin counter stained with eosin, 

 fuchsin, and light green as the best stains. The work is divided into two phases; the 

 first deals with the morphology and cytology of the mycelia and the second treats of results 

 obtained from the study of single spore cultures of Coprinus fimetarius. — The mycelia o f 

 the three species of fungi Miss Bensaude studied were obtained from germinating spores as 

 well as from material collected in the field. The author accepts R. Falck's classification of 

 the mycelia into primary, secondary, and tertiary forms. The claim is made that the first 

 few days after the germination of the spores in Coprinus the resulting mycelia belong to 

 the primary class in which the hyphae are partitioned off into cells which contain from 

 one to many nuclei. These uninucleated cells may give rise to varying numbers of uninu- 

 cleated oidia.— Disarticulated hyphal cells which she calls "pseudoidia" are also formed 

 which may germinate like true oidia. The nuclei in the germ tubes apparently divide 

 amitotically. — Cross walls with clamp connections never appear in the hyphae of the primary 

 mycelia. Miss Bensaude grew single spores of Coprinus fimetarius in pure cultures. She 

 succeeded in isolating single spores. In two cultures of these, abundant mycelium was 

 produced, which remained primary and did not produce carpophores. When parts of each 

 mycelium were mixed in a culture, a secondary mycelium appeared and fruit bodies were 

 produced. The chief method of bringing about the plasmogamy seems to be through the 

 union of a hyphal cell of one thallus with an oidium from another thallus, although it may 

 be brought about by the anastomosis of two hyphal cells of different thalli in C. fimetarius. 

 Miss Bensaude thus concludes that the "dicaryon" in C. fimetarius is formed following 

 plasmogamy between cells coming from two different thalli. — The transformation of a primary 

 mycelium into a secondary mycelium is very difficult to observe. The fusion of two cells 

 (plasmogamy or pseudogamy) introduces the cytoplasm and nucleus or nuclei of one cell into 

 the other. This results in the establishment of a binucleated cell. If two cells unite which 

 have more than two nuclei in common, all disintegrate but two. The uninucleated oidium 

 may fuse with a hyphal cell and this is a very common means of bringing about the initial 

 binucleated condition of the cell. — Each cell in these secondary hyphae is binucleated, 

 constituting a "dicaryon." Conjugate nuclear division occurs in these hyphae as a rule 

 in the apical cell, although intercalary cells divide occasionally. At the time of division 

 the two nuclei move to the middle of the cell and the actual process of cell division is 

 preceded by the formation of a protuberance which is to form a clamp. One of the nuclei 

 which Miss Bensaude calls +, on the basis of her results with single spore cultures, enters this 

 very short branch and the — nucleus remains at about the same level in the mother cell. 

 Spindles are formed and conjugate nuclear division takes place. One of the + daughter 

 nuclei goes back into the mother cell and the other goes to the apex of the young clamp. 

 A cross wall cuts off the beak cell from the mother cell. Of the two — daughter nuclei, 

 one goes to the apical part of the mother cell and the other to the basal part, and a cross wall 

 is formed at the level of the young clamp dividing the cell into an apical portion with -4- and 

 — daughter nuclei and a basal cell with only the — daughter nucleus. The little beak now 

 fuses with the basal cell and its nucleus passes into this cell so that it also becomes binucleated. 

 Very often the apex of the beak fuses with the mother cell before nuclear division takes 

 place. — Reversion of secondary to primary mycelium occurs, in which case a uninucleated 

 cell appears among binucleated cells. No clamps are found on the cross walls of this cell. 

 These uninucleated cells may bear oidia. [See Bot. Absts. 3, Entry 597.] — Michael Levine. 



348. Btjrt, E. A. The Thelephoraceae of North America. IX. Aleurodiscus, Ann. Mis- 

 souri Bot. Gard. 5: 177-203. 1918. — Fourteen species are included. It is pointed out that 

 the limits of the genus are indefinite. The species are characterized especially by unusually 

 large basidia and by noteworthy paraphyses. [See Bot. Absts. 1, Entry 774.) — H. M. 

 Fitzpatrick. 



349. Burt, E. A. The Thelephoraceae of North America. X. Hymenochaete. Ann. Mis- 

 souri Bot. Gard. 5:301-372. 1918. — Thirty-six species are recognized for North America. 

 The genus is characterized primarily by the possession of "slender, somewhat conical colored 



