JEHANGIR FARDUNJI DASTUR. 181 



under its pressure the wall gives way (Plate II, Fig. 6). In petioles 

 and in stems the hypha emerges singly as a rule, as in the case of 

 leaves, but occasionally a cluster of four or five have been found to 

 come out from the same point (Plate II, Fig. 7). 



The mycelium within the tissues is both intracellular and 

 intercellular. Wherever an intracellular hypha passes through 

 a wall there is invariably a constriction of the hypha (Plate II, Fig. 2). 

 Haustoria are very scarce. Hartig 1 has described them to be button- 

 shaped in Ph. Fagi (Ph. omnivora de Bary), Coleman' finger-shaped 

 in Ph. omnivora, var. Arecce, Klebahn 3 short thick and finger-like in 

 Ph. Sy ring 03 and Ph. omnivora, while de Bary says, " Bestimmte 

 Haustorien sind nicht vorhanden " but in Ph. parasitica 

 both finger-shaped and button-shaped haustoria have been found 

 (Plate III, Figs. 2 B and 3) ; they branch very rarely. Whether these 

 bodies which we call haustoria are true haustoria or the initial stage 

 of branches of the intracellular hyphae arising from the intercellular 

 mycelium remains an open question. No cellulose cap has been 

 observed at the tips of these finger-like or button-shaped bodies 

 which would leave no doubt as to their identity. In Plate III, Fig. 

 2, A is distinctly a branch of the intercellular hypha but B may be a 

 haustorium or a branch like A in a very early stage ; but, on the 

 other hand, in Plate III, Fig. 4, A appears to be a branched 

 haustorium. 



When a diseased petiole or stem is cut transversely, the ring of 

 fibro-vascular bundles becomes prominent by its black or brown 

 colour on account of the fungus choking the vessels (Plate II, 

 Fig. 2). Ph. omnivora de Bary and Ph. omnivora, var. Arecce Coleman 

 have been known to attack the vascular bundles. The hyphee of 

 Ph. parasitica enter and leave the vessels of the fibro vascular 

 bundles through their unthickened portions. The hypha 

 at the point of entrance or exit generally swells, the thin 



1 Hartig, R. Untersuchungen ausdem forstbotanischen Institut zu Munchen, 1880, p. 41. 



2 (oliman, L. C. Diseases of the Arena Palm. Dept. of Agric, Mysore State, Myc. Ser. 

 Bull. No. 2, 1910, p. 82. 



3 Klebahn, H. Krankhciten des Flieders, 1909, pp. 42 and 43. 



