THE ASPERGILLUS OCHRACEUS GROUP 285 



in diameter, occasionally as much as 500m, pale olive-buff to olive-buff 

 (Ridgway, PI. XL) upon Czapek and hay infusion agars to pale olivine or 

 olivine (Ridgway, PI. XXXII) upon malt extract agar. Conidiophores 

 straight, mostly 1 to \\ mm. in length by 10 to 12m in diameter, approxi- 

 mately uniform in diameter throughout, wall 1.2 to 1.5m in thickness, 

 conspicuously echinulate, typically arising from a foot cell enmeshed in a 

 network of "feeder" hyphae, often tapering abruptly in the region im- 

 mediately beneath the vesicle. Vesicle comparatively thin-walled, globose 

 (fig. 76 D), mostly 40 to 50m in diameter, occasionally larger or smaller, 

 bearing sterigmata over the entire surface. Sterigmata in two series, 

 primaries crowded, comparatively short and stout, commonly 8 to 10m by 

 3 to 5m, secondaries 6 to 8m by 2.5 to 3.5m- Conidia pale yellowish in mass, 

 individually showing slight coloration, subglobose to slightly elliptical, 

 very finely roughened, mostly 3 to 3.5m in long axis. 



Type culture NRRL No. 1933 was isolated in February 1943, from soil 

 collected in La Lima, Honduras, by Dr. L. A. Llnderkofler. A second strain 

 which duplicates the type almost exactly was subsequently isolated from 

 soil collected in Bixar County, Texas, by Sister Mary Clare of Our Lady of 

 the Lake College, San Antonio, Texas. 



The correct position of this species within the genus Aspergillus is open to 

 question. The presence of a colored, coarsely roughened conidiophore indi- 

 cates close relationship with Aspergillus ochraceas. This is likewise sup- 

 ported by the globose vesicle and head, although these characters are typical 

 of other groups as well. The scarcity of fruiting structures upon all media, 

 and more particularly the greenish tint of the spore masses, however, tend 

 to set it apart from the common representatives of this great group. The 

 general habit of the colonies together with the paucity of conidial structures 

 is strongly suggestive of Aspergillus alliaceus, but this latter species does not 

 show any trace of greenish color in its conidial heads; it does possess smooth, 

 colorless conidiophores, and upon ordinary culture media regularly produces 

 an abundance of black sclerotia which very often dominates and charac- 

 terizes the culture. In the color and character of its conidial heads A. 

 sparsus is somewhat suggestive of George Smith's new species, A. avenaceus 

 (Trans. Bui. Mycol. Soc. 25: 24-27, PI. I. 1943), but it differs from this, 

 as it does from A. alliaceus, in possessing rough conidiophores and in its 

 failure to produce sclerotia. Until additional related forms are isolated, 

 we believe it best to consider this species as a member of the A . ochraceus 

 group, realizing that it does not entirely fit this placement as the group has 

 hitherto been considered. 



Occurrence and Economic Importance 



Members of the A . ochraceus group are widely distributed in nature and 

 can be obtained from a variety of sources. They are especially common 



