230 AGKICULTUEAL EXPERIMENT STATION. [Jan. 



6. The Leaf Glaze. — Acremonium sp. (Plate IV.) 



Early in 1891 cucum])er leaves were received from Fitch- 

 burg, Mass., whose lower surfaces showed delicate glairy 

 films of fungus-threads, as described in our last report.* 

 These leaves came from very badly diseased plants, which 

 had received no benefit from the application of fungicides, 

 although it seemed probable that the accompanying fungus 

 bore some causal relation to the trouble. The fungus-threads 

 on the leaves were quite sterile when received, but, when the 

 leaf bearing them had lani two or three days in the moist 

 chamber, produced spores abundantly. Drawings showing 

 the structure of the fungus and the germination of its spores 

 were made at the time and laid aside, in the hope that addi- 

 tional material would make possible an extension of our 

 knowled<2:e of the disease and of the relations of the fungus 

 in question to it. As it has not again been met with, no 

 further information can be given concerning it, and we can 

 only complete the record of our meagre knowledge of the 

 subject by pul)Ii^hing herewith the drawings mentioned. 



The film on the leaves consists of numerous delicate, 

 colorless and closely interwoven threads. These give rise 

 in the moist chamber, and probably sooner or later under 

 natural conditions, to short simple threads at right angles 

 (fig. 27), at the slightly knobbed apex of each of which is 

 produced a single somewhat kidney-shaped spore (fig. 28). 

 In water these spores swell up and produce stout germ tubes 

 of considerable length, similar to the original threads of the 

 film (fig. 29). This is all we know of the fungus. It is to 

 be hoped that some investigator may be able to study it in 

 detail, with the disease it accompanies, and to answer the 

 many interesting questions concerning it which still await an 



answer. 



7. Otheu Diskases. 



Two other diseases of some importance, which have not 

 yet been observed in JVIassachusetts, but may at any time l)e 

 met with, may be bri(;lly mentioned in conclusion. 



Halsted has described f a serious rotting of cucumbers and 



* Ninth Report Massachusetts Experiment Station, p. 227. 



t Botanical Gazette, 1891, p. 303; and Twelfth Report New Jersey Station, p. 273. 



