430 SUMMARY OF CUKRKNT RESEARCHES RELATING TO 



entirely similar. Above the fusing-cells two short sterile cells are 

 usually developed, their shape being determined by the pressure of the 

 epidermis and of the surrounding cells ; they are the buffer cells, and 

 disappear after fusion has taken place. Fusion between the two gamete 

 cells takes place by the absorption of the intervening cell- walls at the area 

 of contact. Fusions were very frequent in this species. Three or even 

 four cells may fuse together, and may strengthen the view that the sexual 

 processes in the rusts are of a secondary character. The binucleate con- 

 dition was never brought about by migration of the nucleus thi'oughthe 

 cell-wall. Some instances of what appeared to be migrations were noted 

 in the vegetative mycelium, l)ut were considered by the author to be 

 pathological. 



Notes on Evolution of UredineaB.* — J. Pavillard criticizes recent 

 papers that have been published on the sexual evolution in this group. 

 He does not approve of Maire's use of " synkaryon," a term l)orrowed 

 from zoology, and applied l)y Maire to the conjugate nuclei of the 

 Uredines. He regards tlie teleutospore as homologous with the ascus 

 and the basidium, as the seat of nuclear fecundation, the cytological basis 

 of variation and of meiosis, and the point of departure for the in- 

 dividual. 



Synopsis of Stipitate Polyporoids.f— C. G. Lloyd has been working 

 for some time at Polyporacea), and in this pamphlet he publishes the 

 results he has arrived at regarding the stalked forms of the family. He 

 recognizes eleven sections, based on macroscopic as well as microscopic 

 characters, stratifications of the pores {Fomes), colour and form of the 

 spores, consistence of the plant-body and insertion of the stalk. Genera 

 and species are described and figured from photographs. 



Structure and Function of Cystidia.|— F. Knoll has made a study 

 of cystidia in the Basidiomycetes, both of those that are present in the 

 hymenium and those on the surface of the fruiting-body. He looks on 

 them as " hyathodes." They are 1-celled hairs that excrete drops of 

 fluid from their tips. The fluid consists mainly of water, but it con- 

 tains also certain products of metabolism and dissolved mucilage. The 

 cystidia are alike in form and function wherever produced, but hymenial 

 cystidia are by far the most frequent. In certain instances the cystidia 

 contain crystals of calcium oxalate, and on the hymenium they have a 

 protective function. The cystidia of Goprinus are not hyathodes — their 

 function is not well known. 



Influence of Parasitic Fungi on the Cells of the Host-plant.§ 

 E. S. Eeynolds has made a study of the pathological eifects produced 

 in plants by the presence of a parasite. He reviews work previously 

 done on this subject, and gives his own observations in the case of 

 Uredinese, Ustilaginea^, Phycomycetes, and Fungi Imperfecta He 

 studied especially the effect on the nuclei. He found that important 

 nuclear and protoplasmic changes occurred, and were comparable with the 



* Bull. Soc. Mycol. France, xxviii. (1912) pp. 57-9. 



t Bull. Lloyd Library, Cincinnati, Ohio, No. 20, pp. 95-208 (106 figs.). 



+ Jahrb. wiss. Bot , i. (1912) pp. 153-501 (1 pi, and 69 figs.). 



§ Bot. Gaz., liii. (1912) pp. 365-95 (9 figs.). 



