CULTURAL CHARACTEES OF CHESTNUT-BLIGHT FUNGUS. 9 



At 30° C. there was less growth in all cases than at room tempera- 

 ture. E. 'parasitica showed slightly less orange than at room tempera- 

 ture. At room temperature the growth was typical, as described 

 for series 1. At 16° C. the growth in all was almost exactly as 

 described for 18° C, series 1. At 12° C. all were typical in character, 

 but less in amount than at 16° C. At 9° C. there was very slight 

 growth, about uniform in all. At 7° C. there was no growth. 



From these records it will be noted that the minimum temperature 

 for all was 9° C. and that all failed to grow at 7° C. The maximum 

 temperature for Endotliia 'parasitica and E. g'yrosa was 35° C. The 

 maximum for E. radicalis was 32° C. At higher temperatures there 

 was no growth. Thus, there is apparently a difference of 3 degrees 

 C. between the maxima of E. parasitica and E. radicalis. What 

 practical or biological significance this fact may have is not clear to 

 the wi-iters. Owing to a lack of facilities for controlling temperatures 

 between 18° C. and 28° C. the optimum for the organisms could not 

 be accurately determined. The optimum appears to be near ordi- 

 nary room temperature, i. e., about 22° to 24° C. 



DESCRIPTION OF CULTURES. 



In the following descriptions of cultures all names of colors are 

 taken from Ridgway's ^ recent work on color nomenclature. 



No growth whatever was obtained on Eaulin's fluid, beef agar 

 — 15, corn-meal agar +11, and prune agar +11. In the two last- 

 named cases the media were so acid that they would not solidify. 



Potato cylinders. — On ordinary potato cylinders sterilized in an 

 autoclave at 115° C. aU the organisms grew satisfactorily, but no 

 difl'erential characters of value appeared before the cultures dried up. 



Chestnut twigs.- — Cultures on sterilized chestnut twigs showed the 

 same characteristics of growth for Endotliia parasitica and E. radi- 

 calis as described by the Andersors. These species are most easily 

 distinguished on the cut surfaces of the twigs. 



Endotliia radicalis mississippiensis showed at the end of six weeks 

 a cadmium-orange mycelium on the cut surfaces of the twigs, while 

 E. radicalis and E. parasitica were cadmium yellow in the colored 

 portions. 



Endotliia gyrosa showed at first an ochraceous-buff growth on the 

 cut surfaces and later changed to nearly the same color as E. radicalis. 

 E. g'yrosa may, however, even in old cultures, be distinguished from 

 the others by the irregular tubercles or subpulvinate masses of 

 mycelium. 



1 Ridgway, Robert. Color Standards and Color Nomenclature. Washington, 43 p., 53 pi., 1912. 

 98858°— Cir. 131 13 2 



