268 BULLETIN 94. 



weft. In the course of four or five days or one week, from the 

 time that the mycelium is visible to the eye in the culture tube, 

 there will appear first on the stems at certain points, and later on 

 the surface of the glass tube, minute white powdery looking tufts 

 on the mycelium. These are made up of closely and profusely 

 branched threads, the branching sometimes presenting numerous 

 and quite regular dichotomies, at other times quite irregular, and 

 the terminal branches profusely lobed, the lobes standing in all 

 directions and considerably more slender than the threads of the 

 mycelium, and from IO/A to 2o/u, or more in length, occupying the 

 distal portion of the branch for a distance from 20;; to 5<D/x,. 

 Another form of branching will also be present in which the 

 closely set branches diverge at quite strong angles and are quite 

 regularly constricted, presenting a moniliform appearance, and 

 become eventually divided into short cells. These branches be- 

 come more closely compacted and interwoven, forming rotund 

 bodies at first white and quite small but eventually 2 to 4 millime- 

 ters in diameter and of a brown color. These bodies are proba- 

 bly sclerotia. 



Upon the surface of these sclerotia are diverging threads with 

 numerous moniliform cells which resemble chains of conidia. 

 These are not true conidia since they do not easily become sepa- 

 rated. By breaking down the sclerotia or by scraping the sur- 

 face many of them become separated into chains of two or three 

 cells or even become entirely separate. If placed in water, or in 

 suitable medium, they will germinate, thus functioning like 

 conidia. 



The sclerotia have been kept for several months but in no case 

 has any other stage of the fungus been developed from them. 



At present it cannot be correlated with any known group of 

 fungi but there are reasons for supposing that the sclerotia may 

 be the resting stage of some hymenomycetous fungus. Fre- 

 quently the threads become united into rope like strands and 

 change to a brown color. 



DAMPING OFF BY VARIOUS FUNGI. 



Several fungi, probably quite a large number, produce phases 

 of damping off at certain times while their evil effects are not con- 

 fined to this peculiar class of injuries. Phytophthora cadorum 



