744 SUMMARY OF CURRENT RESEARCHES RELATING TO 



tubercle from which the fungus arises ; it is of a spongy texture, and 

 incloses particles of soil, etc. ; attached to this tubercle are various 

 cords of hyphae, which travel in the soil and form here and there the 

 sclerotia-like bodies ; these are clearly in contact with the roots of the 

 higher plants, especially of the elm, of which they form the mycorhiza. 



Cytology of the Ascomycetes.*— H. C. T. Fraser and E. Welsford 

 have investigated nuclear fusion in Peziza vesiculosa and Otidea aurantia. 

 In the former they were unable to recognise an ascogonium, nor were 

 the nuclei in the ascogenous hyphas conjugately arranged ; the divisions 

 of these nuclei are normal, and show about eight chromosomes on the 

 equatorial plate. Fusion in the ascus took place about the time of the 

 first meiotic contraction. In Otidea aurantia traces of a probable func- 

 tionless ascogonium were found ; in the ascogenous hyphas there was no 

 conjugate arrangement of the nuclei. In both species the first and 

 second divisions in the ascus are meiotic ; longitudinal splitting of the 

 spireme was observed in Otidea aurantia. A second reduction or 

 brachymeiosis occurs in the third division, the number of chromosomes 

 being finally two in Otidea and four in Peziza. The two stages of 

 meiosis are cited by the authors as additional evidence of the occurrence 

 of two fusions in the life-history of the Ascomycetes, a phenomenon 

 which has recently been disputed by Claussen. They also studied 

 spore formation, and have confirmed their previous view that the spore 

 is limited by the astral rays, but that these represent cuirents flowing 

 out from the centrosome. They suggest that the centrosome is the seat 

 of fermentative activities and alters the cytoplasm, causing it to form the 

 spore-limiting layer. 



Notes on the Parasitism of Botrytis.f — F. T. Brooks has con- 

 ducted cultural experiments on living plants of lettuce with this fungus. 

 He found that with Botrytis conidia he was unable to infect healthy 

 green leaves, nor even partially weakened leaves ; but wounded leaves, 

 or those turning yellow, were penetrated by the fungus. He found also 

 that if mycelium nourished saprophytically was placed on the same leaves 

 infection took place and spread rapidly. 



M^uld of Fermenting Grain. $ — L. Mangin and N. Patouillard 

 describe three kinds of altered grain produced in Algeria by placing 

 it in silos and allowing it to ferment. One of these products, called 

 Catoimi: grain, becomes injured in the process ; the moulds destroy its 

 nutritive value and communicate toxic properties to it. The authors 

 examined the mould and made cultures, by which they proved it to be 

 Monilia Arnoldi sp. n. They were able to produce the conidial form 

 and the sclerotia, but not the ascus form. Full accounts are given of 

 the d velopment of the fungus. 



C nidial Formation in Aspergillus.§ — L. Mangin has grown species 

 of Aspergillus on various media and under varying conditions to deter- 

 mine the constancy of the factors that are considered of importance in 



* Ann. of Bot., xxii. (1908) pp. 465-77 (2 pis.). 



t Proc. Camb. Phil. Soc, xiv. (1907) p. 298. 



% Bull. Soc. Mycol. France, xxiv. (1908) pp. 156-64 (4 figs.). 



§ Comptes Rendus, cxlvii. (1908) pp. 260-3. 



