Botanical Divibion. 307 



rays. Scale = 1 mm.; object magnified 10 times more than the scale. 

 Drawn with aid of camera lucida. 



The cause being known the remedy would be suggested to all, that 

 too vigorous growth should be guarded against and too severe pruning 

 should not be indulged in. 



GEO. F. ATKINSON. 



ARTIFICIAL CULTURES OF MELANCONIUM FULIGINEUM. 



The suggestion made by Miss Southworth* that the Melanconium 

 fuligineum (Scrib. et. Viala) Cav., should be placed in the same genus 

 with the Ripe Rot of grapes and apples ( Gloeosporium friictigineum, 

 Berk.) led me to make artificial cultures of the fungus for the sake of 

 comparison with cultures of the genus Gloeosporium of the same type 

 as the fructigeniim. Material was obtained from Mr. F. S. Earle of 

 Ocean Springs, Miss, who was kind enough to take the trouble to collect 

 some fallen grapes during the month of February, 1893, from a vineyard 

 which had been affected with the fungus the previous season . A few 

 of these grapes possessed numerous pustules characteristic of Melan- 

 conium fuligineum and which were filled with spores., With these 

 dilution cultures were started in Petrie dishes using ordinary nutri- 

 ent agar. 



In 24 hours the spores were germinating. One to several germ 

 tubes may arise from the spore, usually several. The spores remain 

 continuous, and at first the threads develop septa scantily or indistinctly. 

 The hyphae soon branch and usually profusely quite close to the spore, 

 80 that a rudimentary stroma appears to be developed quite near the 

 center of growth. The spores germinate quite readily in the nutrient 

 agar and growth continues readily for a few daj^s, but no spores were 

 developed in the plate cultures even after a jDeriod of three weeks. 

 Even after the first few days the fungus no longer grew vigorously. 

 The nutrient agar did not supply the needed kind of nourishment for 

 it, or lacked favorable physical properties. 



A few of the colonies of the threads known to have originated from 

 spores of the Malanconium fuligineum were transplanted to culture tubes 

 of nutrient agar, but in a month's time seemed to make no growth or 

 but very little. At the same time several colonies were transplanted to 

 sterilized bean stems in culture tubes. This medium proved to be very 

 favorable for the organic n, for in a few days a profuse growth appeared 



* Journal Mycplogy, Vol. VI., No. 4, 1891, p. 171. 



