6 CIKCULAR NO. 131, BUREAU OF PLANT INDUSTRY. 



mjxelial growth almost filling the tube, at first white; but changing 

 to orange within a few days. 



Pantanelli ^ describes cultures of both species on glucose agar to 

 which extract of chestnut bark had been added. He says the appear- 

 ance and quantity of mycelium was the same in both, but Endotliia 

 radicalis developed a characteristic " giallo-aranciato " yellow- 

 orange color less rapidly than E. parasitica. He also grew both on 

 sterUe chestnut branches and roots. On the roots E. radicalis grew 

 slowly and E. parasitica much less or not at all. 



Fulton ^ mentions cultures on artificial media, stating that EndotJiia 

 parasitica grows most readily on an acid medium. 



Heald and Gardner ^ found that cultures from pycnospores and 

 ascospores of E. parasitica could be distinguished by the earlier 

 appearance of the growth from ascospores in plates. A .3 per cent 

 dextrose agar +10 was used. 



CULTURE MEDIA. 



The following are the principal media and substrata upon which 

 the organisms have been grown: SterUe chestnut twigs, Rauhn's 

 fluid, potato cylinders, chestnut-twig agar, beef agar —15 Fuller's 

 scale, prune agar +11 to —15, corn-meal agar +11 to —15, potato 

 agar +15 to —15; also starch, oatmeal, rice, and white corn meal 

 in flasks. The stock cultures from which subcultures were made 

 were kept on corn meal in flasks. The subcultures, unless other- 

 wise stated, were made by transferring pycnospores from the stock 

 cultures. The cultures were kept in dark cases at ordinary room 

 temperatures, except where otherwise mentioned. 



LIGHT TESTS. 



Two series of spore streaks of EndotJiia parasitica and E. radicalis 

 on potato agar + 6 were placed in a beaker in bright light on a window 

 sill. Duplicate series were wrapped in heavy opaque paper project- 

 ing well above but not covering the plugs. 



After two weeks EndotMa piarasitica showed slightly more orange 

 color in the darkened tubes. This difference was probably due, how- 

 ever, to the fact that evaporation was less in the dark tubes rather 

 than to the want of light. 



1 Pantanelli, E. Su la supposta origine europea del cancro americano del castagno. Atti, Reals Acca- 

 demia del Lincei, ser. 5, Rendiconti, Classe de Scienze Fisiche, Matematiche e Naturali, v. 21, fasc. 12, 

 p. 869-875, 1912. 



-Fulton, H. R. Recent notes on the chestnut bark disease. Conference Called by the Governor of 

 Pennsylvania to Consider Ways and Means for Preventing the Spread of the Chestnut Tree Bark Disea.se. 

 Harrisburg, p. 48-56, 1912. 



' Heald, F. D., and Gardner, M. W. Science, n. s., v. 37, no. 90:3, p. 916-917, 1913. 



[Cir. 131] 



