60 



Mycologia 



An exceedingly important discussion of sugar-cane root disease 

 by Earle and Matz appeared in the Journal of the Department of 

 Agriculture of Porto Rico for January, 1920. A summary of the 

 situation in Porto Rico is given by Earle, as follows : 



Root disease as here understood is a complex including phases often known 

 as Root Rot, Wither Tip, Top Rot and Rind Disease. These phenomena are 

 caused by a number of facultative parasites, none of which attack actively- 

 growing vigorous tissues. There is also a heretofore unknown true parasite 

 inhabiting the vascular bundles. Rhizoctonia and Pythium are the usual root- 

 killing agents rather than Marasmius and Himantia. 



Cane varieties differ greatly in their resistance or susceptibility to Root 

 Disease. The Otaheite or Cana Blanca is very susceptible. North Indian 

 canes like Kavangire and those with part North Indian parentage are very 

 resistant or practically immune. 



Remedial or preventive measures include 



A. The planting of resistant varieties. 



B. Better cultural methods to overcome facultative parasites. 



C. Proper seed selection and handling. 



The parasite inhabiting the vascular bundles is described by 

 Matz as Plasmodiophora vascularum. It is said to differ from 

 P. brassicae in having larger spores, in not forming galls, and in 

 inhabiting the vascular system of its host, plugging up the con- 

 ducting vessels and greatly interfering with their action. 



A New Bolete from Porto Rico 

 Gyroporus Earlei sp. nov. 



Pileus broadly convex, solitary, 8-10 cm. broad; surface 

 slightly viscid when young, becoming dry at maturity, sub- 

 glabrous, fulvous ; margin thin, concolorous ; context fleshy, firm, 

 yellowish-white, unchanging, taste mild, but slightly mawkish; 

 tubes sinuate-depressed, minute, ochraceous at maturity, not 

 stuffed when young; spores ovoid to ellipsoid, smooth, honey- 

 vellow under the microscope, with a very large nucleus, 7-8 X 

 4-5 jx ; stipe somewhat enlarged above and below, bright-yellow 

 at the apex, otherwise very dark brown, almost black, glabrous, 

 solid, firm, 5 cm. long, 1.5-2 cm. thick. 



Type collected in sandy land beside a ditch in an old grape- 

 fruit grove, — where the trees were dying from root disease, — near 

 Manati, Porto Rico, October 29, 1920, F. S. Earle. The descrip- 

 tion is largely drawn from field-notes accompanying the collec- 



