81 



the wrinkles rose little projections no larger than a pin-head. The 

 same were found on the leaves, more frequently on the under 

 than the upper side. On examination, these were found to be 

 little cushions of mycelium threads immediately under the epi- 

 dermal layer. These threads were thin-walled, septate, and 

 filled with minute oil drops ; from this cushion extended Httle 

 rhizoid projections into the spaces between the parenchyma of 

 the host which sent haustoria into these cells. The protoplasm 

 of these cells was contracted and discolored, and the cell showed 

 other appearances of injury. In all respects the fungus and its 

 effects on the host appeared like that of some of the family of the 



Uredineae. 



In order to discover what the further development might be, the 

 end of the branch was fresh cut and placed in water under a bell 

 jar. Not until after six weeks, and when certain portions of the 

 olive fruit had decayed, was any change perceptible. Then the fun- 

 gus began a further development, the mycelium threads lying 

 next the epidermis sent up numerous little tubes parallel with 

 each other and at right angles to the hyphse branches, thus form- 

 ing a sort of hymenial layer. These tubes, at first slender, after- 

 ward swelled out into oval shaped bodies. The epidermis was soon 

 broken, leaving these exposed to the outside air. Soon after this 

 stage, a cross wall formed in many of these tubes, cut off the 

 swollen part, which after a short time developed into a pear-shaped 

 spore, was provided with a roughened outer coat and finally sep- 

 arated itself from the rest of the plant. The remaining tubes 

 appeared like ordinary paraphyses growing up thickly about the 

 spores and projecting above them. 



But the most remarkable part of the development is yet to 

 come. Just after the hymenial layer originates and the spore 

 tubes begin to assume their characteristic form, the whole myce- 

 lium cushion begins to undergo a rapid series of changes, by which 

 it is transformed into a bundle of densely wound hyphse. That 

 portion of these directly under the central part of the hymenial 

 layer send out branches downward which, growing rapidly at 

 right andes to the surface, interweaving with each other and 



is"*- ""fc) 



growing together, form the beginning of a stem whose growth is 

 arrested at this stage, till the hymenial layer is well organized 



