440 SUMMARY OF CURRENT RESEARCHES RELATING TO 



He gives the methods of fixation and staining, and the species of 

 fungi in which he studied this subject. They were selected chiefly 

 from the larger Discomycetes. The results are followed out in detail 

 in the case of Ahuria cerect, and a resume is given of special points 

 noted in the other species examined. 



The mother-cell of the ascus, he finds, is derived from a filament 

 with bi-nucleate cells, which bends over like a crook ; the nuclei each 

 divide, and a cell is cut off at the bend containing the two central 

 nuclei, which fuse. The cell then grows in length and forms the ascus. 

 At first it is filled with a dense cytoplasm, but gradually this becomes 

 vacuolated and the metachromatic corpuscles make their appearance in 

 the meshes between the vacuoles, not only in the neighbourhood of the 

 nucleus, but through the entire length of the cell. Glycogen was also 

 found in the epiplasm and globules of oil, which are secreted in the 

 same manner as the corpuscles. Guilliermond considers them all to be 

 reserve bodies. He did not find that the corpuscles were bodies acting 

 on glycogen and transforming it into oil, nor were they elaioplasts 

 for the formation of oil. These different bodies exist separately or 

 together in different cells. The final absorption of the corpuscles by 

 the maturing spores proves that they, as well as the other bodies formed, 

 were reserve material to be used up in the growth of the spore. 



In one of the fungi examined, a species of Peziza, it was found that the 

 ascus was formed in a slightly different manner. The primary cell did 

 not bend over. The nuclei divided and remained attached in pairs as 

 in the basidiomycetes, the cell elongated, and the upper cell with its 

 pair of nuclei was cut off and formed the ascus. The nuclei fused, and 

 development proceeded as in the other cases. The writer notes the 

 appearance of the band of amyloid round the operculum of the ascus 

 in Ahuria ; he does not consider it to be a reserve body in this in- 

 stance, its function being concerned with the escape of the spores. 

 He confirms Harper's work on the development of the spores in the 

 ascus. 



Critical Notes on Exoascacese.* — R. Sadebeck describes a new 

 Exoascus found on a member of the Euphorbiacese. He found three 

 types of ascus present on the leaves attacked. They were long and 

 slender, or short and clavate, or of an ovate form on a long slender stalk- 

 cell. The author is quite certain that the first two forms belong to one 

 fungus, and he thinks it very probable that the third is also part of the 

 same growth, though the polymorphism of the asci is as marked as it is 

 unusual. The number of spores varies from four to eight in each ascus ; 

 the hymenium is formed under the cuticle of the leaf. He calls the new 

 species E. Sebastiancz. 



Specialisation of Parasitism in Erysiphacese.t — E. S. Salmon has 

 continued his inoculation experiments with Erysiphe Sphcerotheca on 

 various host-plants. The results, he says, seem to show that in every 

 case the form of the fungus has become specialised into a " biologic 

 form." In each experiment the conidia of the fungus were used, but 



* Ber. Deutscli. Bot. Gesell., xxii. (1904) pp. 119-33 (1 pi.). 

 t New Phytol., iii. (1904) pp. 109-21. 



