30 Bui^LETiN 125. 



simply little tufts of threads about the size of a pin-head, but later they in- 

 creased to several times that size. They were then pure white, somewhat 

 compacted, and cottony in appearance. When examined under the micro- 

 scope, these cushions were found to consist of erect parallel hyphae, much 

 like fertile threads, but no conidia have yet been detected upon them. 



On the currant stems in the Bhrlenmyer flask growth was at first slow. 

 In a few days, however, a long sparse growth of mycelium could be seen 

 spreading thinly over the surface of the stems. In a short time the mycel- 

 lium became somewhat flocculent in spots, especially at the cut places where 

 branches had been removed from the stems. After fourteen days growth, 

 the white cushions began to be formed, especially at the cut surfaces men- 

 tioned. In appearance these were exactly like the ones described on the 

 bean stems. When old they became yellowish, and closely compacted into 

 a stroma, which was slightly pinkish within. Several instances have been 

 noted in which a swelling or protrusion appeared at the summit or side of 

 one of the white cushions, and which seemed at first to present every indica- 

 tion of a forming perithecium. It was soon found, however, that the pro- 

 trusion was simply a true, pink stroma oiTubercularia, resembling in nearly 

 every respect those found in nature. Conidia were present in great numbers 

 at the summit of the mass. In the flask, also, on the felty mass covering the 

 surface of the currant leaves and liquid at the bottom, small pink tubercles 

 have arisen, which in many respects resemble those found on the currant 

 stems in nature. 



It may be mentioned at this point, that in none of the artificial cultures 

 has there appeared any indication of the fruit-bodies described by Mayr*^ 

 as macroconidia. These were said to be long, fusoid, several-septate bodies, 

 borne on tufts of white mycelium, at points where the stromata of Tuber- 

 cularia later appeared. The macroconidia after germination produced 

 secondary macroconidia of a similar form, by budding-olT from the mycelium. 

 It was thought at first, that the white cushions mentioned in the last 

 paragraph might represent these macroconidial stromata, but a careful 

 search has failed to reveal any f ruiting-bodies of such a form. The fact that 

 no such bodies appeared in the carefully made pure cultures, together with 

 their very marked similarity to the conidia of a very common saprophytic 

 fungus of the genus Fusariiun has raised the suspicion that perhaps the 

 macroconidia may have belonged to another fungus not connected with 

 Tubercularia. 



In order to determine the function of the secondary conidia thrown off 

 from the mycelium growing in agar, dilution cultures were made, that they 

 might be obtained in pure cultures. This was done by transferring a por- 

 tion of a Tubercularia colony, containing numerous secondary conidia, to 

 three agar tubes successively and pouring into plates in the ordinary manner. 

 Plate number one was then examined under the microscope, and the posi- 

 tion of the conidia marked on the glass. After twenty-two hours these 



•Untersuch. a. d. forst-botan. Inst, zu Miinchen. 3 : 1-16, PI. I, figs. 18-21. 



