42 



CULTURAL STUDIES OF SPECIES OF PENICILLIUM. 



Potato Btarch 3 per cent, slow development but characteristic. Butterfat, little or 

 no growth. 



Cooked apple, mycelium yellow, ascigerous masses produced most quickly (1 week). 



Milk, grows poorly; curdling (with 0.25 per cent calcium chlorid) none; diges- 

 tion slight and slow. 



At 37° C, grew well; at 20° C, more slowly. 



PENICILLIUM DUCLAUXI Delacroix. 



Bulletin de la Societe Mycologique de France, Tome VIII, 1891, p. 107, PI. VII. 



Colonies grown upon gelatin and potato or bean agar clear dark green to olive when 

 old, consisting of short crowded conidiophores arising for the most part singly from 

 the substratum (strict), but sometimes producing short coremia. Long coremia are 

 produced abundantly upon orange, milk, potato, and all media rich in cane sugar. 

 Conidiophores very short, 10-50/*, either arising directly from the substratum or borne 





Fig. 9. — Penicillium duclauxi Delacroix: a, b, conidial fructifications with young conidia smooth, from 

 potato-agar plate culture, simpler types (X 900); c, d, e, conidial fructifications from potato-agar plate 

 culture, more complex types (X 1,400); /, g, h,j, sketches of habit upon potato agar, showing the very 

 short conidiophores arising from the substratum ( X 140); k, ripe spores highly magnified to show delicate 

 markings (X 900, apochromatic); J, m, n, germination of conidia (X 900, apochromatic); s, t, coremia, 

 (sketch). 



upon the upper third of the coremia, 1-2 septate, bearing a simple conidial fructifica- 

 tion or a terminal fructification and a divergent lateral branch with a whorl of coni- 

 diiferous cells. Conidial fructification often 100-160/£ in length consisting of a few eoni- 

 diiferous cells 10-12/t in length in a simple terminal whorl or less commonly in 

 secondary whorls. Conidia elliptical fusiform 3.6-4 by 2-2. 5/i, clear homogeneous green, 

 smooth when young, but rugulose when ripe. Colonies liquefy sugar-gelatin in Petri- 

 dish culture slowly from twelfth to twenty-fifth day and change red litmus to blue in 7 

 days. Produces a coloring agent in sugar media which is wine red in alkaline media 

 and yellow (bile-yellow) in acid media (acts as an indicator with neutral point very 

 near that of phenolphthalein). 



This fungus is characterized by its enormous development of coremia upon milk, 

 orange, apple, and media containing cane sugar, while producing only very short 

 conidiophores in bean or potato agar and gelatin free from sugar. 



Received from the author, George Delacroix, Paris, but one culture previously 

 obtained from P. H. Rolfs in Florida in the summer of 1905 was thought to be this. 



