510 The Ohio Naturalist. [Vol. IX, No. 7, 



In an effort to secure more perithecia from this material a 

 number of spots were cut from leaves that were dried and laid 

 away at the time of collection. These spots were placed in 

 water to soften and after a few hours a part of them was taken 

 out, killed, imbedded, sectioned and stained. Upon one of these 

 spots both perithecia and pycindia were found (Fig. 9) similar to 

 those before discovered upon separate spots — a fact pointing to 

 the probability that both fruiting bodies sprang from the same 

 mycelium. A few of the leaf spots not imbedded were left in 

 the water for several days and when again examined showed a 

 vigorous growth of mycelium which was producing in abundance 

 the chain-like spores of an Alternaria (Fig. 4). A number of 

 other spots similarly treated gave like results. A more thorough 

 investigation of the specimens labeled Macrosporiiim catalpae 

 was now made by soaking some of the spots in water and then 

 mounting them in glycerin. This revealed conidiophores and 

 chain -like spores (Fig. 5) similar to those mentioned above, 

 from which it appears that the fungus known as Macrosporiiim 

 catalpae is a species of Alternaria. Furthermore, one of the 

 spots from which sprang mycelium bearing spores of Alternaria 

 showed among its conidiophores a perithicium as shown in 

 figure 7. 



In July the writer received a supply of infested leaves from 

 Mr. Erwin F. Smith, of the Bureau of Plant Industry, at Wash- 

 ington, D. C, collected from catalpa trees in that vicinity. Upon 

 the spots on these leaves a species of Alternaria was found 

 flourishing and when they were removed from the leaves, placed 

 in a moist watch-glass and covered with a small bell jar a vig- 

 orous growth of mycelium sprang up producing an abundance of 

 spores in chains. As far as it was possible to determine by 

 comparison, these spores were in all respects similar to those 

 developed in a similar manner from leaves collected at Columbus. 

 From the spores developed from leaves collected at Washington 

 an artificial culture was made from which a pure culture of the 

 fungus was secured. In August three young catalpa trees with 

 leaves representing all stages of development were thoroughly 

 sprayed with sterilized water in which an abundance of the 

 spores from this pure culture had been placed. These trees were 

 growing in a small court with walls on four sides and were in a 

 thrifty, vigorous condition. The spores were sprayed upon 

 them in the evening of a day on which at about noon a heavy 

 rain had fallen. The next day was warm and cloudy and the 

 moisture sprayed upon the plants in the evening was still visible 

 upon them at noon the following day. The conditions seemed 

 to be exceptionally favorable for tlic development of the spores 

 yet not a single spot appeared upon the leaves of any of the 

 trees. Spores taken from the same source at the same time and 

 placed upon an artificial medium grew nicely thus showing that 



