ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 219 



Ustilagineae."" — Alden A. Potter and G. W. Coons s^ive notes on 

 the differences between Tilletia Isevis and T. Tritici. These consist 

 in their effect on the flowering-stalk, and in the sori on the smutted 

 grains. The distribution of the two species is also discussed. 



UredineaB. — E. C. Stakman f has carried out a series of infections 

 of Timothy-grass by Puccinia graminis in order to study the possible 

 origin and developmental tendencies of biologic forms. The uredine of 

 Timothy-grass, Puccinia Phlei-pratensis, resembles very closely the bio- 

 logic form P. graminis-avenae, and the latter was used in the inoculations. 

 It was found possible to infect with this fungus, but the spores produced 

 were considerably reduced in size. Practically the same results were ob- 

 tained when barley was used as the host-plant. Stakman considers that 

 P. Phlei-pratensis may thus have been evolved through P. graminis- 

 avense. 



R. H. CoUey % has found the teleutospores of Gronartium rihicola 

 developing internally in the petioles of Rihes, chiefly in the pith and 

 pericycle region. Such development has been recognized in the rusts, 

 and should be regarded, he says, as a rather common teratological 

 phenomenon. 



R. E. Stone § gives a note as to the distribution of Gymnoconia 

 inter stiticd is in Canada, an orange-rust of Ruhiis spp. Notes are also 

 given of the germination of the spores of the Geeoma stage. 



J. R. Weir and E. E. Hubert || have made a series of inoculation 

 experiments with the spores of Hyalospora Polypodii, which grows 

 frequently on Woodsia, and of H. aspidiotus on Phegopteris. The 

 results of their experiments went far to prove that these rusts have no 

 alternate hosts, that they winter over by means of teleutospores, and are 

 propagated during the summer by uredinia. 



E. C. Stakman and F. J. Piemeisel^ give descriptions and results of 

 experiments with the biologic forms of Puccinia graminis on cereals and 

 grasses. Tables are given showing the inoculation results from one host 

 to another, and the effect of external conditions. A long summary of 

 the results obtained is appended. 



Paul C. Standley ** publishes a Hst, with copious notes, of rusts and 

 smuts collected in New Mexico in 1916. The species are not new, but 

 in some the hosts are new. 



J. R. Weir and E. E. Hubert ff have made observations on the over- 

 wintering of rusts on forest trees, and find that a number continue 

 growth by means of the uridineal stage. 



The same writers %% ^^so publish results of cultures of Melampsorella 



* Phytopathology, viii. (1918) pp. 106-13 (4 figs.). 



t Journ. Agric. Kesearch, vi. (1916) pp. 813-16. 



X Journ. Agric. Research, viii. (1917) pp. 329-32 (1 pi.). 



§ Phytopathology, viii. (1918) pp. 27-9 (1 fig.). 



II Phytopathology, viii. (1918) pp. 57-8. 



«jf Journ. Agric. Research, x. (1917) pp. 429-95 (8 pis.). 

 ** Mycologia, x. (1918) pp. 34-42. 

 tt Phytopathology, viii. (1918) pp. 55-9. 

 XX Phytopathology, viii. (1918) pp. 114-8. 



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