GLIOCLADIUM, PAECILOMYCES, AND SCOPULARIOPSIS 699 



172C), often 150/x in length in old colonies, ^ierigmatic cells often con- 

 tinuous with the conidiophores, variable, up to 20m by about 3.0 to 4.0m, 

 sometimes tapering to slender conidium bearing tubes, in other cases essen- 

 tially uniform in diameter throughout. Conidia somewhat pear-shaped, 

 thick-walled, characteristically tuberculate (fig. 172D) but smooth when 

 young and often appearing so in liquid mounts under oil immersion, com- 

 monly measuring 6.5 to 7.5m by 7.5 to 9.0m, avellaneous to Hght brown in 

 mass, viable for several years, germinating by a single tube from the thin 

 center of the broad base into a bulbous enlargement from which mycelial 

 hyphae about 2m in diameter arise. 



Colonies on steep agar usually growing more rapidly, tending to be looser 

 in texture, and often sporulating somewhat more abundantly than upon 

 Czapek agar. Their general appearance and color is, however, essentially 

 the same. Conidial structures duplicate those seen on Czapek. 



Colonies on malt agar are usually thin, and often very restricted in 

 grow^th. Sporulation varies from abundant to almost lacking, depending 

 upon the strain. 



Colonies digest milk and liquefy gelatin with a strong ammoniacal odor. 

 They grow very rapidly upon neutral or alkaline media, but more slowly or 

 hardly at all in acid media, hence their appearance on malt agar. 



Members of the genus Scopulariopsis vary greatly in the shade of yellow- 

 brown produced in conidial areas, including occasional forms which are 

 white or nearly so. None produce true green spores, although certain 

 forms have been assigned to the genus which produce conidia with walls 

 pale greenish black. Conidia may be smooth or rough, and vary greatly 

 in shape, size, and intensity of color. The appearance of a truncate base 

 appears to be consistent and characteristic of all forms. No one has yet 

 reported a comparative study of the group from which valid lines of sepa- 

 ration among species could be established. 



Thorn, in 1910, recognized two varieties of Scopulariopsis brevicaulis 

 (Sacc.) Bainier (as P. brevicaule Sacc.) based upon the character and color 

 of the conidia produced in strains under examination. Penicillium brevi- 

 caule var. album was established to include occasional strains encountered 

 in cheese investigations which had rough but colorless conidia. The variety 

 did not otherwise differ from the species. Penicillium brevicaule var. 

 glabrum was established to include strains with smooth-walled colorless 

 conidia. Culturally, this variety Ukewise duplicated the species except 

 for an absence of avellaneous color (fig. 172E) and the production of smooth- 

 walled conidia (fig. 172F). 



In his Monograph, Thom (1930) included but did not attempt to classify 

 descriptions of species reported up to that time. Since that date many 

 additional species have been described. 



