DARLUCA ON PERIDERMIUM PECKII* 



J. F. Adams 

 (With Plate 21) 



The genus Darluca in the family Sphaeropsidiaceae of the 

 Fungi Imperfecti includes species which are reported on the 

 leaves of deciduous plants as well as being parasitic on the 

 Uredineae. 



Darluca filum (Biv.) Cast, is a species most commonly men- 

 tioned as a frequent parasite on various species of Uredinales. 

 Saccardo 15 states that it is uredinicolis and Sydow 18 and Grove 9 

 refer to it as a parasite growing on the uredo layer. Lindau 11 

 reports it as cosmopolitan on aecidia of various uredinia. Ros- 

 trup 14 lists it on Chrysomyxa abictis (2346). Cornu 7 says it at- 

 tacks the telia of Puccinia Prunorum and Puccinia Caricis. 

 Fuckel 8 finds it on urediniospores of various species and telio- 

 spores of Uromyces Cytissi. Tulasne 19 reports Diplodia punc- 

 tata which corresponds to Darluca filum on Uredo jarinosa, U. 

 falicis, U. Euphorbiae and U. Epilobii. Broisi 3 has mentioned 

 this parasite on Puccinia bromia and Puccinia Triseti. 



McAlpine 12 finds it quite common for the uredo-layer to be at- 

 tacked by this fungus and has found it upon 24 per cent of the 

 species of Puccinia. " It occurs on aecidia, uredo and teleuto 

 layers, and is recorded on Uromyces, Uromycladium, Puccinia, 

 Phragmidium and in Uredo. 



Cobb 6 unquestionably discusses this same parasite in connection 

 with the peach rust ( Tranzchelia punctata) . He states " I fre- 

 quently find among the Uredospores of a parasite of this rust 

 small black pycnidia producing a multitude of two-celled spores, 

 which when placed in a moist chamber often bud and multiply 

 after the manner of yeast plants, but which occasionally produce 

 a mycelium. Further, I find in the pustules of a number of Aus- 

 tralian rusts similar tiny black pycnidia, producing similar two- 



* Contribution from the Department of Botany, The Pennsylvania State 

 College, No. 23. 



309 



