THE ASPERGILLUS OCHRACEUS GROUP 281 



commonly 7 to 10/x by 1.5 to 2.5/x. Conidia globose, subglobose, or some- 

 what elliptical, more or less rough or echinulate, ranging from 3.5 to 5.0m 

 in long axis. No perithecia reported. Sclerotia are present in Wilhelm's 

 material preserved in exsiccati. 



Among the great number of isolates belonging to this group a considerable 

 number show approximately the characters as drawn from Wilhelm's 

 description and his exsiccati. In the limited sense then, ^4. ochraceus 

 Wilhelm can be interpreted to apply to those ochraceous strains which bear 

 echinulate conidia from 3.5 to 5.0m in diameter and produce sclerotia. 

 Among the strains included, almost all are found to produce colonies of 

 consistent aspect in continuous culture. 



Aspergillus elegans Gasperini, in Atti. Soc. Toscana Sci. Nat. Pisa 



Mem., 8: 328, fasc. 2. 1887. 



Synonym: S. elegans (Gasp.) Sacc, in Syll. 10: 525. 



This species by description differs little from A. ochraceus Wilhelm 

 except for the absence of sclerotia, and conidia which do not exceed 3.5/x 

 in diameter. Thorn and Church did not recognize it as a valid species in 

 1926, and one may be certain that no sharp line can be drawn separating 

 A. elegans from A. ochraceus. Nevertheless, forms producing conidia con- 

 sistently less than 3. 5m are commonly encountered among miscellaneous 

 isolations from nature, and there is an argument for retaining a species to 

 include such forms. The following species diagnosis, taken from Saccardo 

 (10: 525) was presented by Thorn and Church (1926): 



"Mycelium white; stalks continuous, unbranched, hyaline then pale 

 ochraceous, 1 to 6 mm. long, by 5 to 12/x in diameter, delicately studded with 

 drops ; vesicle up to 70m diameter, radiate, entirely covered with sterigmata; 

 sterigmata, primary 4 to 26m long, secondary 7 to 14m long by 1 to 2m; 

 conidia ochraceous, elliptical to globose, up to 3 to 3.5m, with wall very deli- 

 cately verruculose, sclerotia not found." 



Various other species have been described which are obviously closely 

 related and belong to the A. ochraceus series. A partial list would in- 

 clude : 



S. helva Bainier, in Bull. Soc. Bot. France 28: 78. 1881. Thorn's culture No. 

 4640.476, received under this name, came from the Bainier collection. 



A. alutaceus Berkeley and Curtis (in Grevillea 3, No. 25, p. 108. 1875) was the 

 name proposed for a mold found upon corn. The specimen is preserved as No. 3793 

 in Curtis' Herbarium now in the Cryptogamic Herbarium of Harvard University. 

 The specimen shows that this species was probably a strain of A. ochraceus. 



A. ochraceus var. microspora Tiraboschi (in Ann. di Bot. [Rome] 7: 14. 1908) 

 represents a strain in which all measurements were reported as reduced. 



A. rehmii Zukal. A culture from Dr. Westerdijk, received under this name, is also 

 a member of this series. 



