608 SUMMA.RY OF CURRENT RESEARCHES RELATING TO 



sown, and out of twenty-one plants that ^rew, thirteen were found to 

 be smutted. Seeds were also microscopically examined and the mycelium 

 "was found to be most abundant in the scutellum, though also present in 

 various other parts of the embryo. Cultures of the fungus taken from 

 infected seeds were successfully carried out on gelatin, potatoes, etc., and 

 the resulting mycelial growth was employed to reinfect leaves or stigma 

 of other plants. 



Seeds of artificially infected plants were tested. Of 409 seeds so 

 examined 162 were found to contain the mycehum of the smut Ustilago 

 Hordei-niida. 



Two New Grass Smuts.* — These are described by Ewen Mac 

 Kiniion, and were found on species of Panicum. Diagnoses are given 

 of the new species, and a detailed account of the germination of the 

 spores of each. The first species dealt with, Sorosporhim Panici^ is con- 

 fined within the glumes and converts the ovaries into black spore-masses ; 

 the other Ustilago panicigraciUs alters the inflorescence, forming a con- 

 tracted and irregularly swollen boil-like growth. 



Culture of Cereal Rusts. f — F. D. Fromme has demonstrated the 

 possibility of carrying on a continual series of rust cultures in the green- 

 house for the purpose of physiological study, and he ^ives an account of 

 his methods and results. 



Two rusts, Puccinia dispersa on rye and P. coronifera on oats, were 

 kept going on living hosts by him for a consecutive period of six months. 

 P. coronifera was also maintained for a period of eight months with 

 transfer of infection once a week. During this time the rusts went 

 through 37 generations of the uredo stage without any resulting decrease 

 in the power of infection. The rust does not, however, self -propagate 

 to any extent. Very simple methods of infecting were found to be 

 successful : the host-plant— generally a seedling — was first sprayed and 

 then an infected pot plant turned upside down and shaken over it. 

 The spores that dropped sufficed for infection. 



A high degree of humidity w^as found to be the essential factor, and 

 infections were secured only when humidity of the atmosphere was 

 maintained by covering the cultures with a bell-jar for twenty-four 

 hours, subsequent to the application of the spores. 



While increased temperature was favourable to the development of 

 the fungus, the exclusion of light checked the growth. It was found 

 also that uredospores of P. coronifera, when stored at room temperature, 

 gradually lost their capacity for germination ; after eighty days' storage 

 only • 2 p.c. were still germinable. 



The mildew Erysiplie graminis was a troublesome intruder in the 

 cultures, but it w^as possible to control it by treatment with sulphur 

 dust. 



Uredinese.l — W. P. Fraser has proved by inoculation experiments 

 that the fern rusts of the genus Urediniopsis are heteroecious and that 



* Journ. Proc. R. Soc. N.S.W., xlvi. (1912) pp. 201-4 (4 pis.), 

 t Bull. Torrey Bot. Club, xl. (1913) pp. 501-21. 

 i Mycologia, v. (1933) pp. 233-9. 



