A TROPICAL PYRENOMYCETOUS FUNGUS. 349 



middle (fig. 5). In outline, therefore, it is oval or oblong. 

 It presents a somewhat thick, strongly carbonised, brittle 

 exospore, which gives it the dark colour, and which is 

 externally studded with numerous, closely set, minute, stiff 

 papillae, Avhich project perpendicularly from all parts of the 

 surface; closely lining the inside of this is a thin endospore, 

 scarcely recognisable through the dark, opaque outer wall. 

 At that part of the spore corresponding to the slight indenta- 

 tion of the outline, a distinct, firm septum divides the whole 

 into two equal halves. The granular protoplasm usually 

 contains one or two nucleus-like oily drops, though no true 

 nucleus could be discovered. 



On sowing such a spore in water on the upper surface of 

 the jasmine leaf, a blunt outgrowth from the end of each of 

 the two chambers is soon established as a pale, granular- 

 looking, blunt hypha, with a diameter equal to about one 

 third that of the spore. This germinal hypha branches and 

 forms one or two septa very soon after its emergence, and 

 its walls then acquire the brown colour of the adult fungus. 

 This hypha presents the ordinary appearance of a germinal 

 tube, with double contour, and pale granular protoplasmic 

 contents. The first branches are usually very irregular and 

 stumpy, sometimes acquiring a knobby appearance, from the 

 formation of one or two close-set septa; one of the ends, 

 however, at length grows forth more directly, and rapidly 

 produces a long, straight, or sinuous hypha, which becomes 

 divided at pretty regular intervals by septa, like those of 

 the first-formed tube, and which gives off branches to the 

 right and left as it proceeds. 



This more vigorous forward growth of the germinal hypha 

 is preceded, in many cases, if not always, by the formation of 

 a haustorium, from the point where one of the first-formed 

 stumpy branches clings to the epidermis. This sucking 

 organ pierces the subjacent cuticle and cell-wall (fig. 5) by 

 a long, very slender, curved neck, which ends below in an 

 ovoid, nearly uniform granular mass. All parts of this organ 

 are hyaline and colourless, contrasting sharply with the 

 brown hypha whence it springs. 



The growing end of the hypha is pale and almost colour- 

 less, the thickening and carbonising of the cell-wall com- 

 mencing a little behind this point ; the diameter remains the 

 same, however, up to the bluntly rounded apex. As the 

 main germinal hypha proceeds to form the network of 

 mycelium, a zig-zag course comes to predominate from the 

 manner of branching. Some of the branches grow out — 

 very commonly at an angle of about 60° (c/. fig. 2) — as main 



