ENDOTHIA PARASITICA AND BELATED SPECIES. 41 



(PL XXI, fig. 1) in field work when fructifications of the species 

 are wanting or doubtful. 



Aside from the differences in color, the most conspicuous and 

 important characteristic of these fungi in corn-meal cultures is 

 found in the fructification. Clinton (18, pi. 26) has already men- 

 tioned and illustrated similar differences in cultures of these organ- 

 isms on agar in Petri dishes. In Endothia parasitica the pycnidia 

 and spore masses are small, numerous, thickly scattered, and em- 

 bedded in the mycelium. E. fluens, on the other hand, forms few, 

 large, erumpent stromata, with spores extruding in thick, elongated 

 masses. E. tropicalis closely resembles E. parasitica in number, size, 

 and arrangement of pycnidia and spore masses, but differs in color 

 of mycelium. E. ftuens mississippiensis appears somewhat inter- 

 mediate between E. parasitica and E. fluens in regard to the character 

 and abundance of the pycnidia and in color of the growth. These 

 peculiarities have been very uniform and constant in all the cultures 

 on this medium and if they could be coordinated w r ith regular mor- 

 phological differences in nature would justify the separation of this 

 form as a species. (See Pis. XIX and XX.) 



CULTURES ON LIQUID MEDIA (IN 100 C. C. FLASKS). 



Some difficulty was experienced at first in growing the species of 

 Endothia satisfactorily on a liquid medium. Abundant growth was 

 obtained on a medium suggested by Dr. Mel. T. Cook. This is a 

 modification of the liquid medium No. II as given by him (19). 



Cook's liquid medium, No. II, is prepared as follows : 



Into 500 c. c. of distilled water put 15 grams of glucose and 20 grams of 

 peptone steamed at 100 C. for three-fourths hour; into another 500 c. c. of 

 distilled water put 0.25 gram of dipotassium phosphate and 0.25 gram of 

 magnesium sulphate, steamed for 20 minutes; filter both 500 c. c. into same 

 receptacle, steam 10 minutes, put into flasks, about 30 c. c. in each flask, and 

 autoclave. 



All species grew readily on this medium, Endothia parasitica even 

 producing pycnospores. At the end of one month's growth the sev- 

 eral species were readily distinglished on this medium and may be 

 briefly described as follows: 



Endothia gyrosa. Growth scanty; did not form a continuous mat, but re- 

 mained in small bunches, giving an almost flocculent appearance. The mycelium 

 appeared white when removed from the culture solution, but the solution itself 

 was honey yellow. 



Endothia singularis. Growth even less abundant than E. gyrosa; formed 

 small brown knots against the glass. Mycelium buff, and the medium was 

 changed to honey yellow. 



Endothia fluens. Growth somewhat more abundant and less closely matted 

 than E. parasitica, entirely submerged; mycelium white; liquid unchanged in 

 color. 



