184 A MANUAL OF THE PENICILLIA 



acid, C. oxaUcus from a saturated solution of oxalic acid, and C. lacticus from a 4.5 

 percent solution of lactic acid. The observations recorded are inadequate and fail 

 to provide separating morphological characters. They probably belong to the Peni- 

 cillium frequentans series, but closer diagnosis is impossible. 



PenicilUum flavo-cinereum Biourge (Monograph, La Cellule 33: fasc. I, pp. 293-295; 

 Col. PI. VIII and PI. XIII, fig. 76. 1923) was reported by Thom, in 1930, as belonging 

 "in the series with P. spinulosum Thom". Examination of two strains received in 

 February 1946 from the Centraal bureau bearing this name shows one to be a fairly 

 representative culture of P. frequentans Westling; the other P. spinulosum Thom. 

 The latter culture, now maintained as NRRL 2051, shows conidia commonly ellipti- 

 cal, especially as seen in chains in fluid mounts, but is otherwise typical. We do not 

 believe adequate bases exist for maintaining Biourge's species, which undoubtedly 

 represented a member of the P . frequentans series probably closest to P. spinulosum, 

 as earlier indicated. 



PenicilUum mediocre Stapp and Bortels, in Zentbl. f. Bakt. etc., (II) 93: 50. 

 1935. The authors described their organism as from the soil of a pine forest. Col- 

 onies upon wort agar spreading, bluish green to green with a broad sterile margin 

 and scanty development of aerial hyphae; in reverse, yellow or orange at high tem- 

 peratures, optimum growth at 26°C., conidiophores borne mostly as branches of 

 aerial hyphae, rough-walled, up to 80 to 100^ long by 2 to 3fj. in diameter, apices vesi- 

 cle-like; sterigmata in groups of 5 to 10, definitely rough-walled, 6 to lOju by 2 to 3m, 

 and conidia globose, rough, 2 to 3m in loosely parallel chains. No data is given to 

 separate this from P. spinulosum. Growth is possibly less rapid than in typical 

 P. spinulosum and conidia are listed as slightly smaller. 



PenicilUum mucosum Stapp and Bortels, in Zentbl. f. Bakt. etc., (II) 93: 51. 

 1935. The species was described as from "soil" in a beech forest, and deposited with 

 the Centraalbureau. Our examination of the type strain, as received from Professor 

 Westerdijk, indicates close relationship to P. spinulosum Thom without sufficient 

 cultural or morphological differences to warrant continued recognition of Stapp and 

 Bortels species. Conidia are globose, spinulose, about 2.5 to 3.0m; conidiophores 

 arise from the substratum and from trailing hyphae, are about 2.0 to 2.5m wide, and 

 are definitely roughened; penicilli are usually strictly monoverticillate, produce long 

 parallel or tangled chains of conidia rarely in well defined columns; colonies in reverse 

 show dull reddish purple shades suggestive of P. purpurrescens. 



Citromyccs pfefferianus Wehmer, in Beitr. z. Kenntn. einheim. Pilze I: 22-24; 

 Taf. I, figs. 1-13. 1893. Wehmer found his organism on rotting fruits of Citrus 

 medica and cited it as the agent of citric acid production in his patent. Morphologi- 

 cal data as given might indicate any one of many strains of monoverticillate Peni- 

 cillia. Verified cultures were never distributed. By 1905, so many monoverticillate 

 forms had been cultivated that he acknowledged that he could no longer recognize 

 either of his two original species. There is persistent belief that C. pfefferianus was 

 some member of the species aggregate now designated as PenicilUum spimtlosiim. 



PenicilUum pfefferianum (Wehmer) Westling, in Arkiv for Botanik 11: 132-133. 

 1911 (also in Biourge's Monograph, La Cellule 33: fasc. 1, pp. 303-305; Col. PI. VIII 

 and PI. XII, fig. 72. 1923). Biourge attributes to Westling a strain which is now 

 contained in our collection as NRRL 727, brought by Dr. Paul Simonart from Bi- 

 ourge's Laboratory. It shows the morphology of this group, but produces deep dark 



