449 



THE RED STRING OF THE SUGAR-CANE 



{Bacillus pseudarabixus, n.sp.). 



Bv R. Greig Smith, D.Sc, Maclkay Bacteriologist to the 



Society. 



(Plates xiii.-xv.) 



The presence of red-coloured vascular strings in the sugar-cane 

 is not at all uncommon. The phenomenon appears to accompany 

 several diseases of the cane, and at the same time canes which 

 are to all appearance healthy may exhibit the colour. Among 

 the diseases there are (1) the Sereh Disease, concerning the 

 etiology of which there is much doubt; (2) the Sugar-Cane 

 Disease of Massee, caused by Trichosphaeria sacchm'i, Massee,* 

 and a similar disease, the Pine-apple Disease of the Cane, described 

 by Wentf as being produced by Thielaviopsis ethaceticus, Went; 

 (3) the Red Smut of the Sugar-Cane, occasioned by Colletotrichuyn 

 falcatum, Went, and this is undoubtedly identical with Cobb's 

 Red Rot of the Sugar-Cane. j The instances of red string that 

 I have investigated were not, however, related to any of these 

 diseases, for they occurred in cases otherwise healthy and in 

 plants affected with gummosis. The phenomenon must not be 

 confused with the red-coloured tissue of some decayed canes, for 

 in such cases the red colour only indicates that the cellular tissue 

 is dead. 



The first example of Pted String that I examined was the case 

 of an apparently healthy cane which had only three or four 

 coloured bundles in cross section. The sample was small and 



* Massee, Ann. Bot. vii. 525; also in Text Book of Plant Diseases, London, 

 1899, 103, 365. 



t Went, Ann. Bot. x. 583. 

 I Cobb, Agric. Gazette N.S. Wales, 1893. 



