310 BROOKLYN BOTANIC GARDEN MEMOIRS 
phore bears a single spore. Successive production of spores on the 
same conidiophore, such as has been described by Miyabe (7) for 
M. parasiticum Thiim., has not been observed for M. solani. Occa- 
sionally the spores are borne in chains of two. This may occur quite 
frequently when the atmosphere above the culture is saturated with 
water vapor and only a few conidiophores are being produced by a 
vigorously growing mycelium. It occurs very seldom or not at all in 
cultures that are sporulating abundantly. The occurrence of spores 
in chains of two is exceptional for M. solani. The writer has never 
observed longer chains and is inclined to the view that Duggar (1) 
is correct in leaving this fungus in the genus Macrosporium rather than 
to put it into the closely related genus Alternaria as Jones and Grout 
(5) have done. Duggar’s objection that the catenulate method of 
spore production has not been seen except in artificial culture does 
not hold, however, for the writer has more than once observed the 
spores in chains of two on the potato leaf. M. daturae when grown 
under very moist conditions also produces its spores in chains of two. 
This fungus in rare instances even produces spores in chains of three. 
Under more normal conditions, however, the spores are always borne 
singly. As one finds it growing on its host or observes it in pure cul- 
ture, the catenulate method of spore production is exceptional, and 
it seems doubtful whether any useful purpose would be served by 
transferring it to the genus Alternaria. The writer has examined 
many fruiting cultures of the tomato parasite, but has never observed 
it producing spores in chains even under very moist conditions. 
Besides usually producing their spores singly, both the early 
blight fungus and the jimson-weed fungus show other characteristics 
which seem to put them with the Macrosporiums. They both possess 
a coarser mycelium than is usual for the genus Alternaria. Their 
spores are larger and under most conditions are produced in smaller 
numbers than is common for an Alternaria. Moreover, their spores 
are normally attenuated into a beak similar to that on the spores of 
other species of Macrosporium, such as M. catalpae, E. & M., M. 
cucumerinum, E. & E., M. caudatum, C. & E., M. concentricum, 
Winter, M. brassicae, Berk., M. porri, Ellis, and M. tomato, Cooke. 
M. caricinum, one of the four species mentioned by Fries (2) at the 
time he established the genus, bears spores which are, according to 
his description, attenuated at both ends. No such beaks are to be 
observed on spores that are borne in chains. 
Since M. solani, M. tomato and M. daturae are parasitic on closely 
related plants, they have by some authors been considered identical. 
Sorauer (9) seems to have had this notion and Duggar (1) states that 
M. solani ‘“‘is found not only upon the potato but also upon tomatoes 
