693 



originates from the Javanese name for Andropoijoti Schoenanthus (Jav. 

 Sereh), grown extensively in gardens there. This grass forms unusually 

 greatly branched bushes. In its most highly developed form the disease of 

 the sugar cane also appears in an excessive formation of short lateral shoots 

 which make the plant look bushy. The root system is poorly developed and 

 only slender roots spread out in the soil; the majority remain short and 

 bushy, for their ti])S die and those formed anew fall victim to the same fate. 

 Many parasites are found in the dead tissue ; among these, Tylenchus Sac- 

 chari Soltw. is the most common in Java. The internodes of the stem 

 remain short ; the eyes of the leaf axils swell up round, while, in the normal 

 cane (with the exception of a few varieties) they lie flat like a shell in the 

 small depressions on the stem. The growth of the main shoot is sup- 

 pressed and, on this account, the lower eyes, especially those below ground, 

 develop quickly. In the new shoots, however, the same process of sup- 

 pression of the apical growth is repeated immediately as well as that of the 

 breaking of the secondary axes. In this way the whole plant gets an obnor- 

 mally bushy formation. The Javanese material, which I ordered for inves- 

 tigation, at times showed such a ramification of the lateral axes on tlie 

 upper, higher parts of the stem that groups, resembling witches' brooms, 

 were formed. All possible transitions between this bushy dwarfing and the 

 slender normal condition are found in the different stages of the disease. 



As a result of the great shortening of the internodes, the leaves stand 

 close to one another like fans. The leaf sheaths seem to enclose each other. 

 In many cases, their death does not take place as it does normally by 

 advancing from the edge towards the mid-rib, but conversely, and the result 

 is that they remain for a long time on the stem and form nests for micro- 

 organisms. Their color is usually darker than that of the normally dead 

 leaves and while the latter are tough, the abnormal ones are more brittle 

 and disintegrate easily. The intensive red colored vascular bundles are at 

 once conspicuous in a cross-section throvtgh a node of the diseased cane. 

 This coloring matter may be withdrawn with alcohol. The cell walls are 

 frequently swollen out of shape and partially destroyed. 



This red coloring of the bundles occurs in cuttings and in older plants 

 in the first stages of the disease, so that it was thought that they should be 

 emphasized as a characteristic especially deserving of consideration. 



We have observed this red coloring of the cell walls in many non- 

 parasitic diseases of monocotyledons, and Busse^ has been able to produce 

 it artificially in the sorghum millet in German East Africa by painting the 

 leaf blades with vaseline or paraffine oil. The color spread still further in 

 the xylem parts of the vascular bundles and was traced by Busse to a dis- 

 turbance in the respiratory process. We consider the red color to be a 

 phenomenon of oxidation which indicates a functional disturbance in the con- 



1 Busse, Walter, Untersuchungen liber die Krankheiten der Sorghum-Hii'se. 

 Arb. d. Biol. Abt. f. Land- u. Forstw. am Kaiserl. Gesundheitsamte 1904, Vol. IV, 

 Part 4, p. 319. 



