374 SUMMARY OF CURRENT RESEARCHES RELATING TO 



sound grains with the organisms and reproducing "yellow-grains." He 

 recommends care in keeping rice dry as a protection against the disease. 



Studies of Dothideacese.* — F. Theissen and H. Sydow have made a 

 study of the published genera and species of this family of Pyreno- 

 mycetes. Many imperfectly developed species have been deleted and 

 others have been placed in new genera : (1) Tricliodothis, the first new 

 genus, has a superficial stroma. The terminal cells of the hyphae on the 

 margins of the perithecia grow out and form a crown of radiating 

 filaments. One species only, T. comata, is placed in the genus ; 

 (2) Phragmodothis is also a new genus with an erumpent stroma, the 

 spores are dark brown and 3-septate ; (3) Trabutiella is similar to 

 Trabutia, but without paraphyses ; (4) Pgrenobotrys is without a 

 stroma, or reduced to a loose mycelium which traverses the matrix ; 

 (5) Stalagmites, based on Dothidea tumefaeiens ; (6) Rehmiodothis , which 

 is similar to Trabutia, but with hyaline spores ; (7) Phseodothiopsis, 

 based on Dothidea Zollinger i ; and (8) Parmulina, very like Parmularia, 

 but the stroma attached at the centre. 



Relationships of Floridese and Ascomycetes.f — A long discussion 

 of the different modes of sexual development in Floridea?, Ascomycetes, 

 and Lichens, is published by B. 0. Dodge. The paper is well illustrated 

 by figures in the text, either original or taken from the publications 

 quoted. Dodge gives in detail the history of the discoveries already 

 made in connexion with the reproductive organs of Ascomycetes, laying 

 emphasis on the formation and function of a trichogyne ; he includes 

 lichens in the survey. He cites the instances in which the trichogyne is 

 branched ; in Laboulbeniacea3, in Collema microphylliim, in Lecanora 

 subfusca, and in Pgronema. This trichogyne is contrasted with that of 

 the red algge which is a simple structure of constant type, being merely a 

 prolongation of the egg-cell. The formation of the ascus is next discussed, 

 and its morphological characters which constitute a difficulty in all attempts 

 to derive the Ascomycetes from the Florideas. Dodge, however, considers 

 that the " Ascogenous hypha? of fungi and lichens, gonimoblasts of the 

 Batrachospermum type, ooblastema filaments, and even those fusions 

 between cells of the ascogonium are all to be considered morphological 

 equivalents." The form of the fruit is also considered, and Dodge 

 suggests that the Discomycetes with an exposed hymenium may be more 

 primitive than the Pyrenomycetes, which are permanently closed. The 

 various types of formation are fully described and compared. 



In conclusion, he looks to the future for further evidence, since 

 " new data as to the morphology of the ascogonium and trichogyne are 

 accumulating rapidly. Many lichens are provided with trichogynes. and 

 where no such structure has been found, an ascogonium has generally 

 been more or less clearly recognized. It is not improbable that further 

 research will disclose manv other interesting forms such as we now find 

 in Collema pulpo sum, Ascobolus carbonarius, and A. magnificus." 



A complete bibliography of the works consulted is added to the 

 paper. 



* Ann. Mycol., xii. (1914) pp. 176-94. ' 



t Bull. Torrey Bot. Club, xli. (1914) pp. 157-202 (13 figs.). 



