526 A MANUAL OF THE PENICILLIA 



days, and within a week usually attain a diameter of 2.5 to 4.0 or 5.0 cm., 

 varying with the strain and the amount of inoculum used. Selected strains 

 almost invariably rot oranges more rapidly than lemons as measured by the 

 diameter of the affected areas. Strains of P. urticae Bainier, when sim- 

 ilarly inoculated into sound lemons and oranges produce a more restricted, 

 dry, brownish to almost black rot (usually 1.0 to 2.0 cm. in 7 to 8 days) 

 which extends to the center of the fruit, causing a definite purplish dis- 

 coloration throughout the area of the core. Other species of Penicillium 

 when tested failed to produce any evidence of rot. The limited infections 

 produced by P. urticae are regarded as indicating a possible degree of 

 relationship to P. italicum., but not sufficiently close to be included in the 

 series with it. 



Wehmer described sclerotia in Penicillium italicum but failed to find 

 ascospores. Thom (1910) also reported sclerotia but failed to describe 

 them adequately. Schwartz (1926) found a strain of P. italicum. (identifica- 

 tion confirmed by Wehmer) that produced clumps of sclerotia upon oranges, 

 and which, after a twelve-week ripening period, developed ascospores 

 which he reported as smooth- walled, measuring 2.6 by 3.9/i with a narrow 

 equatorial "ring." Although Thom (1930) tried many times, he obtained 

 no ascospores from his transfer of Schwartz's strain. Schwartz's report 

 suggests that he may have been working with some member of the Car- 

 penteles series. 



Penicillium. italicum Wehmer, in Hedwigia 33: 211-214. 1894. See also 

 Beitr. z. Kennt. Einh. Pilze, II, pp. 68-72; Taf. I, figs. 1-3, Taf. II, 

 figs. 1-10, Jena, 1895. Thom, The Penicillia, pp. 412-414, fig. 63. 1930. 



Colonies on Czapek's solution agar growing restrictedly, attaining a 

 diameter of 2.0 to 2.5 cm. in 10 to 12 days at room temperature, with cen- 

 tral area 1.0 to 1.5 cm. wide commonly raised and ranging up to 2.0 mm. 

 deep, often marked by a few shallow furrows (fig. 135A), with margins 

 usually thinner and in some strains almost plane but showing evidence of 

 fasciculation, in others strongly fasciculate, sporulating irregularly but 

 seldom heavily, usually more abundantly in marginal to submarginal re- 

 gions, with conidial areas typically in pale gray-green shades near court 

 gray to gnaphalium green but in some strains more yellowish near pea 

 green (Ridgway, PL XLVII); odor fragrant, suggesting perfume, variously 

 diagnosed as "lavender or lilac"; exudate lacking or very limited in amount, 

 clear; reverse variously colored in pale gray to yellowish bro^vn shades, 

 often zonate; conidiophores arising from the substratum or occasionally 

 from superficial hyphae on or near the agar surface, variable in length up 

 to 250m or more by 3.8 to 5.0^ in diameter, with walls smooth, commonly 



