1913] CURRENT LITERATURE 163 
organs are only partly modified. The many resulting types are described in 
detail by the author. The degree of transformation is correlated with the state 
of development of the primordia at the time that they are infected. e 
influence of the fungus evidently does not extend beyond the tissue actually 
invaded. These conclusions, however, are drawn from observations of the 
visible transformations. No histological details, which would be —— 
interesting in this case, are reported. 
DieTeEL’ has published a second instalment of his studies on the factors 
influencing the germination of teleutospores. Among the results reported 
the following are of interest. The teleutospores of Melampsora Larici-Tremulae 
Kleb. are capable of germinating in March and later. Their germination 
takes place readily at temperatures between 8° C. and 26°C. In the study of 
Puccinia graminis Pers., it was found that the abnormal mode of germination, 
sometimes observed in teleutospores of this species, is determined by the 
temperature. At temperatures below 23° C. normal germination takes place, 
but at higher temperatures the teleutospores simply produce long germ tubes 
which occasionally become segmented. A similar mode of germination of the 
teleutospores of P. Malvacearum has been observed by TAUBENHAUS’ and also 
by Ericksson,’ who attributes to the ‘‘conidia’’ abjointed by the segmentation 
of the germ tube a special function in the biology of this rust. Duxeret finds, 
however, that in P. Malvacearum the formation of sporidia, or of germ tubes 
which segment into ‘“‘conidia,” is determined by the conditions under which 
germination takes place and not by functional differentiation of the spores. 
High temperature and lack of moisture favor the production of abnormal 
germ tubes. 
To the few observations which have been made on the transmission, from 
the stock to the scion, and inversely, of grafted plants, of qualities producing 
immunity from the attack of fungi to which one or the other is subject, FIscHEr® 
adds a further observation supporting the general conclusion that no such 
mutual influence between the stock and the scion exists. He finds that So 
of Mespilus, which cannot be infected by the basidiospores of Gymnosporangiu 
confusum, remain immune even when united by grafting with sctictble 
species of Crataegus, nor is the susceptibility of the Crataegus chang 
special case is presented by Crataegomespilus Asnieresii, which is a 
chimaera consisting of a Crataegus core with a Mespilus epidermis. Here 
FIscHER found that the germ tubes of the basidiospores penetrated the epi- 
dermis and infected the Crataegus tissue underneath. He reserves his opinion, 
however, as to any mutual influence of the two parts of the plants, stating 
ETEL, P., Versuche iiber die LO ARE LASSE der Teleutosporen einiger 
‘Gucdudeas II., Centralbl. Bakt. II. 35:272-285. 190 
7 Rev. in Bor, GAZ. 54:431-433- 1912. 
* Fiscuer, Ep., Beitrige zur Biologie der Uredineen. Mycol. Centralbl. 1: 195- 
198. Ig12. 
