478 SUMMARY OF CURRENT RESEARCHES RELATING TO 



floating in the air. These methods have been adopted in various schools 

 with great success. The technique of fungus cultivation, with the 

 necessity for cleanliness and sterilization of plates, etc., is fully explained. 

 A list of the pure cultures of fungi that can be obtained from the 

 publishers of the paper is also given, and the macroscopic characters of 

 each culture, such as colour, rate of growth, etc., are noted. 



By J. Ramsbottom, M.A., F.L.S. 



North American Peronosporales.* — G. W. Wilson, in his sixth 

 contribution to this subject, deals with miscellaneous species of this 

 group. Notes are given on the history and occurrence of certain rarer 

 species and their microscopic characters described. A new genus 

 Bremilla is diagnosed, and two new species Peronospora Chamsesycis 

 and P. minima. Several new combinations are made. 



Cytology of Sporodinia.f— M. L. Keene publishes her results 

 obtained in the investigation of the sexual process in Sporodinia grandis 

 ■ — a fungus which has been worked with by numerous cytologists. In 

 the early stages of copulation of the sexual branches there is no differ- 

 ence morphologically between the two branches. Later, there is a 

 characteristic retraction of the protoplasm of one of the gametangia. 

 This may or may not be of sexual significance. The nuclei of the 

 gametangia are small and show the same structure, size, and staining 

 reaction as those of the mycelium. Vacuoles and cleavage furrows are 

 formed. A new membrane is produced by ingrowth from the lateral 

 walls. A central thickened portion is formed. The wall between the 

 gametangia is dissolved, and the gametes fuse, the protoplasm of the 

 one flowing into that of the other. Nuclear fusions occur progressively 

 as the protoplasmic masses mix. As a result there are two sizes of 

 nuclei present, large nuclei which result from fusions, and small nuclei 

 which have failed to fuse. The formation of the second wall of the 

 zygospore then takes place, and the unfused nuclei, as well as those of 

 the suspensors, begin to show degeneration. Mucorine crystals are 

 present through all the earlier stages. There next appear globular 

 cytoplasmic structures, with which from their first appearance, oil is 

 associated. They fuse irregularly, and produce ultimately one or two 

 large bodies which are saturated with oil. These large cytoplasmic 

 bodies are undoubtedly related to the elaioplasts described in many 

 plants, and have for their function the elaborntion of an oil for reserve 

 food. In the mature zygospore there are numerous characteristic nuclei 

 formed by the fusion of the two nuclei. The protoplasm is reduced to 

 a thin parietal layer surrounding the oil plastid. The state of affairs 

 persists until germination. 



Oil Drops in Discomycete Spores.} — E. Boudier again calls atten- 

 tion to the importance which should be attached to the oil drops or 



* Mycologia, vi. (1914) pp. 192-210. 



f Ann. of Bot., xxviii. (1914) pp. 455-70. 



j Rev. Gen. Bot., xxv bis (1914) pp. 51-4. 



