MONOVERTICILLATA 



167 



and was discussed under this number by him in connection with this species 

 in his Monograph (1930). 



When grown on malt extract and steep agars, the species is characterized 

 by the production of definite sclerotia, or sclerotia-Uke bodies. Such struc- 

 tures have not been observed in our cultures grown on Czapek agar, nor 

 were they apparently observed by Thorn in 1930. Biourge likewise failed 

 to report such structures although the strain obtained from his laboratory 

 shows them in equal abundance to the strain obtained from Westling 

 directly. In his original description based upon colonies grown on prune 

 gelatine, Westling (1911) reported the presence of numerous colorless to 

 yellowish perithecia 55 to 105/u in diameter, which Thom (1930, p. 207) 



Fig. 47. Penicillium turbatmn Westling, NRRL 757. .1, Two-week-old colony on 

 malt agar. B, Sclerotia as seen in marginal colony area, X 65. 



interpreted as sclerotia since no ascogenous stage was reported. Repeated 

 examination of these structures in our current study has likewise failed to 

 show any sign of asci or ascospores. 



The presence of sclerotia in a strictly monoverticillate form having ellip- 

 tical conidia suggests close relationship to Penicillium thomii Maire. The 

 sclerotia in P. turhatum, however, differ markedly from those of P. thomii. 

 They are consistently smaller, comparatively soft, crush easily, and are 

 composed of parenchyma-like cells with walls only moderately thickened. 

 The species is keyed adjacent to the P. thomii series but is regarded as some- 

 what separate from it because of the difference in sclerotia. 



Penicillium pusillum Smith, in Brit. Mycol. Soc. Trans. 22: 254-255, PI- 



XVI, figs. 7 and 8. 1939. 



Author's diagnosis as follows: 



"Colonies on Czapek agar growing very slowly and restrictedly, attaining a diam- 

 eter of about 1 cm. in 12 days and thereafter spreading very little, pale bluish gray, 

 gradually becoming overgrown with white to vinaceous mycelium, thin and tough. 



