30 



CULTURAL STUDIES OF SPECIES <JE PEKICILLIUM. 



of a main branch and one lateral branch, each producing a whorl of branchlets bearing 

 crowded verticils of conidiiferous cells, 12-14 by 3^. Conidia breaking off in masses in 

 handling old cultures, which rise in clouds when shaken. Pronounced odor in cul- 

 tures containing cane sugar. Chains of conidia loosely divergent, long; conidia 

 2-3 by 3-5/t, cylindrical to elliptical or slightly ovate, clear green by transmitted 

 light, very variable in size but usually within the limits given. Masses of spores con- 

 tinue to increase from 2 to 3 weeks. Petri-dish colonies partially and slowly liquefy 

 gelatin (12 to 20 days). Numerous white sclerotia are produced upon the surface of 



Fig. 2.—Ptnuittium italicum Wehmer: a, b, c, d, c, f, g, types of branching, formation of verticils of 

 conidiiferous cells and conidial chains (a, e, /, X 900; 6, c, d, g, X 1,400); j, k, sketches of conidial fructi- 

 fications (X 140); I, m, n, swelling and germination of conidia (X 900). 



the medium after 2 to 3 weeks' growth, especially upon fruits and other acid media 

 rich in sugar. 



Cosmopolitan; characteristic of decaying oranges, which become bright blue-green 

 with this mold as contrasted with the olive-green species which is often associated 

 with it upon the same fruit. These contrasting colors are illustrated by Wehmer. 31 



