626 SUMMARY OF CURRENT RESEARCHES RELATING TO 



cultivated on the same medium, otherwise confusion arises, as they 

 develop so differently on various substrata, He himself has followed 

 this method, and yet he has found thirteen new growths that he has 

 been unable to place in any species already described ; these he considers 

 as new. He has figured and described the various forms morphologically 

 and physiologically. 



Important Entomogenous Fungus.*— H. S. Fawcett describes a 

 new fungus, JEgerita Webberi, which lives on the white fly larva?. The 

 white fly, Aleyrodis Citri, is very destructive to orange trees, and the 

 spread of the fungus is secured by artificial methods, either by pinning 

 fungoid leaves among those affected by white fly, or by spraying the 

 trees with water which contains the spores of the fungus. Whenever 

 the atmospheric conditions are favourable to the growth of these fungi, 

 fair success in checking the white fly has been attained. A full de- 

 scription of the fungus is given and of its development on the larva?. 



Hyphomycetes.f — The recent fascicle issued by CI. Lindau completes 

 the work of addition and revision. Most of it is occupied by a key to 

 the genera, and by an index of plants and various substances which 

 serve as hosts, or as substrata, to the various moulds. 



Peridial Cells in the Roesteliae.J— F. D. Kern finds that the 

 peridium of the Roestelise is very characteristic and quite sufficient to 

 distinguish the genus from other Uredineae. He notes the way in which 

 the individual cells are joined together, usually so loosely that they 

 separate easily, and this accounts for the split and ragged condition of 

 most of the peridial walls. The size of the cells varies in the different 

 species, both in length and breadth ; the thickness of the cell-wall is 

 also to be noted ; usually it is thinner on the inner wall than on the 

 others. Only two species have smooth cell-walls, in all the others there 

 is more or less sculpturing, usually ridges or ridge-like markings. The 

 peridial cells of the different species are figured. 



Germination of Uredospores of Hemileia vastatrixi— F. C. von 

 Faber has studied the process of infection of coffee leaves by the spores 

 of Hemileia in Java. They germinate readily on both sides of the leaf, 

 but infection takes place through the stomata and only on the under side. 

 Infection does not take place in too great moisture, even though germi- 

 nating tubes are formed ; it is only when there has been considerable 

 transpiration from the leaf that the fungus is able to enter the tissues, 

 and then it is by means of suckers which develop on the germinating 

 tube. The uredospores germinate in darkness or in weak light, and 

 more readily in a short strong illumination, which seems to act as a 

 stimulant, especially after a period of darkness. Longer illumination 

 has a harmful influence on the uredospores. The blue violet rays exercise 

 a favourable influence if of short duration, but they kill the spores that are 

 exposed to them for a long time. 



* Mycologia, ii. (1910) pp. 164-68 (2 pis.). 



t Rabenhorst's Kryptogamen-Flora, abt. 9, lief. 118 (Leipzig, 1910) pp. 817-80. 



% Bot, Gaz., xlix. (1910) pp. 445-52 (2 pis. and 2 figs.). 



§ Ber. Deutsch. Bot. Gesell., xxviii. (1910) pp. 138-47. 



