592 SUMMARY OF CURRENT RESEARCHES RELATING TO 



experimentation, that an aminoxydase is present in the fungus similar 

 to that found in the yeast of beer, and is located, as in yeasts, in the 

 vacuoles of the cell. As soon as the formation of mucilage begins in 

 Ustilago, the production of the oxydase ceases. The enzyme is most 

 active when there is a maximum of metabolism in the cell, and the 

 resting stage of the fungus follows the period of mucilaginous forma- 

 tion. The author states various theories as to the function of the 

 mucilage. He concludes with an account of spore-germination in this 

 fungus. 



Rust of Andropogon Sorghum.* — Walter Busse has studied the 

 occurrence of this fungus in German East Africa where it sometimes 

 causes very great loss in the crops of millet. He came to the con- 

 clusion that it was the same fungus as that described by Cooke about 

 25 years ago as Puccinia purpurea. The aecidium form is unknown. 

 Uredospores and teleutospores are to be found simultaneously in the 

 same sorus, usually on the under surface of the leaf parallel with 

 the leaf-nerves. The spore-bed is surrounded by paraphyses ; they are 

 somewhat club-shaped and are brownish-yellow or of a deep red colour 

 at the tips. The writer considers that this Uredine is, the same as 

 that described by Barclay as a sorghum rust in India and named 

 by him P. Penniseti. It is said to be " the peculiar indigenous rust of 

 Indian cereals," and is found on a great number of the native grasses. 



Witch's Brooms on the Barberry.f — Jakob Eriksson has proved 

 by experiment that the abnormal branch development of the barberry 

 is due to JEcidium graveolens of which the Puccinia form is produced 

 on Avena elatior. The region of attack is the central bud of the tender 

 rosettes of leaves, although an unfolded leaf is also liable to infection 

 by the Puccinia. According to Eriksson the tissue entered by the 

 fungus is not suppressed, but rather it is excited to a quick and strong 

 branch development. Later arrives a condition of weakness which 

 renders the abnormal branches unfit to resist the cold of winter, and 

 these parts are liable to be killed. The photographic reproductions 

 show a barberry branch with a broom in three stages of growth induced 

 by artificial infection of teleutospores from the Avena host. 



Rust of Timothy G-rass.J — The same author has arrived at the con- 

 clusion that the rust found on Phleum pratense is a separate and distinct 

 species. It has been named Puccinia Phlei-pratensis Er. and Hen. 

 Many infection experiments were tried by the author to trace the com- 

 plete life-history of the fungus. Once he succeeded in inducing ger- 

 mination on the barberry, spermogonia and secidia being sparely 

 produced, after a considerable delay. Somewhat similar results were 

 obtained in the attempts to grow the fungus on rye, wheat, oats, and 

 barley. Only in one case, on oats, did any growth take place. It was 

 found that the uredospores germinated and grew on Festuca elatior, 

 many of the experiments yielding positive results. Eriksson is of 

 opinion that P. Phlei-pratensis was originally identical with P. gram hits, 



* Ber. Deutsch. Bot. Ges., xx. (1902) pp. 2S1-91 (1 pi.). 



+ Colin's Beitrage zur Biologic der Pflanzen, viii. pp. 3-127 (3 pis.). See also 

 Centralbl. Bakt., 2 te Abt., ix. (1902) pp. 75-6. 



J Ofvers. af Kongl. Vet.-Akad. Forh., lix. (1902) pp. 189-98. 



