iqiq] current literature 67 



the control of anthracnose in the southern states. The exact temperature 

 range for Ascochyta and buckwheat was not determined. 



Results obtained by other workers have shown that there is no definite 

 optimum for infection, but that there is a wide range of temperature in which, 

 providing some other factor does not interfere, the number of infections taking 

 place does not vary much if the plant is exposed to infection for a sufficient 

 length of time at the lower temperatures. These earlier results are borne out 

 by the work of Lauritzen. He concludes, therefore, that in considering 

 control measures we must note not only the temperature which seems favorable 

 to infection, but also the length of time for which the plant has been exposed. 



The results he obtains from a study of the effect of humidity on infection 

 lead him to point out that "the absence of certain diseases in semi-arid and 

 arid regions where agriculture has been practised for long periods of time 

 may be due in part to the small moisture content of the air," and that "seasonal 

 variation in the moisture content of the air plays an important part in deter- 

 mining the amount of disease that develops." Because of the rather general 

 belief that a film of moisture on the leaf surface favors infection, it is interesting 

 to note the conclusion reached by the author that such a film is not essential. 

 He considers it proved that, within certain limits of humidity, the spore is 

 able to absorb sufficient water for germination, at first by imbibition and later 

 by osmosis. He suggests also that in depressions of the leaf surface, especially 

 above the stomata. the humidity may be high enough to make germination 

 possible. — D. H. Rose. 



Life history and sexuality of Basidiomycetes. — Miss Bensaude^ has 

 investigated Coprinus fimentarius, Armillaria mucida, and Tricholoma nudum. 

 The work includes two phases: (i) the morphology and cytology of the mycelia, 

 and (2) the results obtained from the study of the single spore cultures of 

 C. fimentarius. 



The mycelia of the 3 species were obtained from germinating spores as 

 well as from material collected in the field. The author accepts Falck's 

 classification of the mycelia into primary, secondary, and tertiary forms. The 

 claim is made that the first few days after the germination of the spores the 

 resulting mycelia belong to the primary class, in which the hyphae are parti- 

 tioned off into cells which contain from one to many nuclei. These uninucleate 

 cells may give rise to varying numbers of uninucleate oidia. Disarticulated 

 hyphal cells, which she calls "pseudoidia," are also formed which, like true 

 oidia, may germinate. The nuclei in the germ tubes divide amitotically. 

 Cross-walls with clamp connections never appear in the hyphae of the primary 

 mycelia. Miss Bensaude grew single spores of C. fimetarius in pure cultures, 

 and succeeded in isolating 10 single spores. Of these, 4 germinated, and in 2 



3 Bensaude, Mathilde, Recherches sur le cycle evolutif et la sexualite chez les 

 Basidiomycetes. Dissertation, pp. 156. pis. ij. figs. jo. Nemours. 1918. 



