484 



Bulletin 315 



Ithaca, N. Y., September and December, 1910, and January, 191 1. Plant 



pathology herbarium No. 5,913. 



The original gives the conidial head as being only 8^n 



in diameter. It is not uncommon to find it measuring 



130/X in diameter. Also, the conidiophores measure as 



high as 400/1. The original gives the mycelium as 



continuous, while it is sparsely septate. 



Penic'illium chrysogenum Thom, Cultural Studies of 



Species of Penicillium. U. S. Dept. Agr., Bur. Anim. 



Indus. Bui. 118: 58-60. yig. 20. 19 10. 



^ , Cultivated in 1 5 per cent gelatin in distilled water, 1 5 



Fig. iig.—Asper- , . , .,..', 



gillus Koninn per cent gelatin plus 3 per cent cane sugar m distilled 



Olid A, conid- -water, potato decoction plus 1.5 per cent agar, potato 

 lophore and ^ . , , ^ ' i 



conidial head, x dccoction plus 3 per cent cane sugar plus i per cent agar, 



9">„^' ^^obo^f at first blue-green, becoming with age slate-gray in agar 

 sivellingoj coma- . , . . . ° . , , , 



iophore, show- and gelatin without cane sugar, where sugar is added to 



mg sterigmata gelatin or agar the colonies do not become as gray as 

 and spores, X 35 5 '^ , " . . , , ,, ,. . , 



where sugar is omitted, broadly spreading m the 



substratum with a wide sterile white margin when young. Reverse 



of colony yellow-green. Conidiophores mostly arising separately, 100- 



250^1 high by 3-5M thick, with 1-3 alternate diverging branches bearing 



once or twice verticillate branchlets. Conidiiferous cells 7-10 by 2-3^1, 



usually in verticils; conidia globose, 3-5. 5m in diameter. Colonies liquefy 



gelatin with alkaline reaction to litmus, and 



in gelatin and on potato plugs a lemon-yellow 



color. 



Hab. Isolated from soil of oat field, Cornell 

 University, Ithaca, N. Y., July and August, 1910, 

 by the writer. 



Writer's culture data: 



Color. — Blue-green to slate-gray when old ; 

 reverse light yellowish green. In some media 

 lemon-yellow; in others, none. 



Odor. — None. 



Fifteen per cent gelatin in water, good growth, 

 lemon-yellow color in gelatin, liquefaction rapid, 

 6-10 days, more or less rapid and complete in 

 all gelatin media used, litmus reaction alkaline. 

 Potato agar, good growth, no yellow color. 

 Potato plugs, good growth, potatoes become 

 yellow. Raulin's fluid, good growth, with age the under surface of mat 

 near test tube assimies a purplish tint, no yellow in fluid. Cohn's solution, 



Fig. 120. — Penicillium 

 chr y so ge n u m Thom. 

 Conidiophore, showing 

 conidial fructification, x 

 236.6; spores, X 533.3 



