24 



The color of the peridium is, however, much more easily modified 

 than that of the ascospores. The latter have always remained brown, 

 no matter on what medium grown ; the former have not always devel- 

 oped a red color. In a few instances the writer has succeeded in grow- 

 ing jierithecia of the cowpea fungus to maturity, and the shedding of 

 ascospores, without the development of any red color in the peridial 

 wall. In a number of other cases the red color has been very slow to 

 appear. It is thus established beyond doubt that the color of, the 

 peridium of a species may be entirely a matter of the particular sub- 

 stratum on which it hai^pens to be growing. The principal diflerences 

 observed in my cultures are given below : 



(1) On steamed potato the fungus fruits copiously, the color of the 

 peridium comes quickly (sixth to ninth day), and is first roseate, then 

 bright coral red. The ascospores are mature in two to three weeks. 

 By the sixth day the substratum has changed from white to dark lead 

 gray. In one instance only (out of a great many) on the upper (dry) 

 end of a potato culture 10 days old many perithecia were still nearly 

 colorless. 



(2) On pearl tapioca steamed with distilled water the fungus grows 

 slowly^ and fruits sparingly; the color of the peridium comes slowly, 

 being first x)ale red and finally black. At the end of 2^- months most 

 of them were destitute of necks, but a few of the black perithecia in 

 one tube had distinct necks. Some of the blackest were removed and 

 examined microscopically. They contained no ascospores or asci. The 

 peridium was brown, but normal in structure. The interior of the 

 perithecia was very full of oil. Some substance necessary to the for- 

 mation of ascospores appeared to be wanting in this substratum. 



(3) On yellow banana steamed with distilled water the fungus grew 

 slowly and fruited only after several weeks, but then copiously. At 

 the end of 5 days there was not one- fiftieth as much vegetative growth 

 as in corresponding tubes of potato. The perithecia were pale j^ellow- 

 ish red. None were bright red, and some were nearly colorless. 



These remarks apply to two cultures made i^ovember 13, from the same 

 culture, and examined December IG. In other cultures the perithecia 

 were ochraceous buff at the end of 20 days. On Jannary 23 the two tubes 

 of November 13 were reexamined and found to be quite unlike. In one 

 the perithecia were now coral-red, had decided necks, and were discharg- 

 ing ascospores— 4. e., j)rotruding them through the ostiolum in brown 

 masses. In the other tube, the shape and the color of the perithecia 

 were both aberrant. This culture was covered all over with perithecia, - 

 but these were globose and destitute of necks; a few were pale coral- 

 red, but most were yellowish brown to dark brown. In the darker 

 ones the structure of the i^eridium could not be made oat without crush- 

 ing the perithecium. There were no ascospores in this culture^ not 



' The amount of growth at the end of 8 days was not one one-thousandth as much 

 as on potato. 



