284 K. YENDO. 



Before the propagating organs of the parasite begin to ap- 

 pear on the surface of the host, the infested part can hardly be 

 recognized unless the staining reaction has been tried on the 

 sections. Just before maturity, as it appears to me, the in- 

 festing cells multiply with great rapidity, running radially and 

 externally towards the surface of the host through its inter- 

 cellular gelatinous matrix (Fig. 12). A wart-like, pale yellowish 

 protuberance is now to be seen, growing on the host. Its 

 height and diameter gradually increase, overlapping the host 

 with its border (Fig. 1). 



A protuberance has but one sort of reproductive organs; 

 but it is not unusual to find protuberances of different re- 

 productive organs on the same frond or even on the same 

 branch of the host. By incidental fusion of two protuberances 

 of different nature, one sort of reproductive organ may occur 

 in one part, and another sort in the other, of one large pro- 

 tuberance. 



The protuberances are built with polygonal parenchymatic 

 cells, much larger, in the inner parts, than the cells of the 

 tissue of the host, but diminishing in size at the periphery. In a 

 well -developed male protuberance I saw the cells at the con- 

 stricted base much narrowed and elongated to run into the host's 

 tissue (Fig. 4). 



The stichidia are elongated conical or fusiform, 0.35 — 0.45 mm. 

 in length, and 0.13 — 0.25 mm. in diameter, standing densely and 

 radially on the wart-like protuberance (Fig. 2). There is no part 

 that can be called stalk in each stichidium, and the base is practi- 

 cally continuous with the vegetative parenchymatous tissue (Fig. 8). 

 The central cell-row may be traced to a certain depth in the vege- 

 tative tissue, but the pericentral cells are distinguishable at the 

 basal part only of the stichidia. The spores are tetrahedral 

 and colourless. Six tetrasporangia are arranged in a whirl around 

 the central cell, with one basal and two guard cells for each 

 (Figs. 9 and 10). 



