346 MORPHOLOGY OF THE ASPERGILLACE^L 



pale brownish yellow, spherical, prickly, tough-skinned spores, 

 15-20 IJL in diameter. The species is found on the excrement of 

 dogs and geese. 



Penicillium aureum, Corda, forms yellow conidial herbages, 

 turning to olive green, with very small, oval to spindle-shaped 

 conidia (3-1.5 /*). The perithecia are thin-skinned, similar to 

 those of the preceding species, but enveloped in a yellow covering 

 of matted hyphae. The spores (5 by 3 p) are smooth, yellow, and 

 ellipsoidal. Corda observed the species on decayed wood, and 

 VAN TIEGHEM (ITT.) found it on the husks of Bertholletia. 

 Further investigation is necessary, though in many respects it 

 so closely resembles P. luteum that the two might be considered 

 identical. 



Penicillium Wortmanni, Klocker, forms ascospores, which are 

 stated by KLOCKER (YI.) to be similar to those of P. luteum and 

 P. aureimi, though they are not smooth or provided with trans- 

 verse ledges, but with stumpy warts, as in the case of P. insigne. 

 How far the resemblance to the latter extends cannot be decided 

 until a more complete description of the conidiophores is 

 available. 



The Penicillium aromaticum, observed by JOHAN-OLSEN (III.) 

 during the ripening of Norwegian " gammelost,"but not described, 

 is probably nothing more than the Penicillium of Roquefort 

 cheese. Particulars are also lacking of the Penicillium forms 

 which certainly included the Camembert Penicillium observed 

 by COSTANTIN and RAY (I.) in Brie cheese. According to the 

 results of investigations by de Seynes, the P. cupricum of Trabut 

 (1895), i g merely a form of the ordinary " P. glaucum" modified 

 by the substratum (copper sulphate solution). 



288. The Genera Citromyees and AlTeseheria. 



The genus Citromyees^ Wehmer, comprises only a few forms, 

 some of which are remarkable, physiologically, for their energetic 

 power of acidification. It differs from Penicillium by the absence 

 of branchings and by the swelling of the conidiophores (often 

 into a globular form), and from Aspergillus by the slenderness 

 of these organs and by the successive development of the 

 sterigmata. The globule is spherical, club-shaped or insignificant. 

 The conidiophores resemble hyphse, are mostly aseptate, and, 

 especially in aged specimens, provided with a colourless, thin- 

 skinned, terminal, club-shaped to spherical globule. They are 

 usually simple, slender, and project in large numbers from 

 the mycelial filaments, the stalks being delicate and barely dis- 

 tinguishable from the vegetative hyphse. The slender, tapering 

 sterigmata are disposed in 5-10 whorls or tufts, pointing upward 

 and inward, so that the head, deprived of conidia, resembles a 

 calyx. The conidia are mostly spherical, very small (under 3 /*), 



