AUTOBASIDIOMYCETES 469 



corresponding to the surface rings. The new growth apparently 

 takes place from all exposed surfaces which are still corky in tex- 

 ture, including the lower margins of the sporophores. Doubtless 

 the sterile basidia continue their growth as vegetative hyphae. The 

 sporophores may be produced high upon the trunks, and since an 

 annual crop of spores is produced, they are most favorably situated 

 to be blown upon other trees. Young conifers are in part protected 

 from infection by the resinous exudates which form over wounds. 

 Control. No method of controlling this fungus is possible, ex- 

 cept by preventing, as far as may be, the causes leading to the 

 breaking of living branches. In well-cared-for forests it is practi- 

 cable to fell diseased trees as promptly as possible or to destroy 

 developing sporophores. 



XI. ROOT DISEASE OF SUGAR CANE 

 Marasmius plica tits Wakker. 



COBB, N. A. Fungus Maladies of the Sugar Cane. Hawaiian Sugar Planters' 



Exp. Sta., Div. Path, and Phys. Built. 6 : no pp. (cf. 24-26, 50). 1906. 

 FULTON, H. R. The Root Disease of Sugar Cane. La. Agl. Exp. Sta. Built. 



100: 1-21. figs. 1-8. 1908. 

 HOWARD, A. On Some Diseases of the Sugar Cane in the West Indies. 



Ann. Bot. 17: 373-411. pi. iS. 1903. 

 WAKKER, ]. H. Eine Zuckerrohrkrankheit, verursacht durch Marasmius Sac- 



chari n. sp. Centrbl. f. Bakt, Par. und Infektionskr. 2 (Abt. 2) : 44-56. 



figs. 1-5. 1896. 



A root disease of the sugar cane in Java was first described by 

 Wakker, and the causal fungus was given as ^farastnius Siicc/iari. 

 A similar disease was subsequently found in other portions of the 

 West Indies, in the Hawaiian Islands, and recently in Louisiana. 

 It is now known to be widely distributed in the southern United 

 Suites. From the work which has been done thus far it seems 

 apparent that several species of Marasmius may be concerned in 

 the production of a more or less common type of root disease. In 

 all cases the fungus appears to be merely a weak parasite, and it 

 frequently gains entrance to the host through the wounds upon 

 cuttings and seed plants. 



Symptoms. Stools of the sugar eane atTeeted by this fungus 

 are commonly smaller and poorly routed, so that the disease be- 

 comes especially evident during conditions of drought. 



