Common Contaminants 353 



(sterigmata) are Formed. Chains <>! spores (conidia) arc seen to develop 

 from the sterigmata. In certain species there is also seen a perithecium, 

 or ascus, which contains spores ( ascosporcs ). Species ol Aspergillus are 

 chiefly identified 1>> the* color ol the spores and special characteristics. 

 Only a lew ol the common species ol Aspergilli arc discussed. 



(a) Aspekgillus GLAUCUS.— This is one ol the commonest contaminants. 

 It has green conidia and yellow perithecia. 



(b) Aspergillus fumigatus.— See Chapter XXXIV, "Fungi Probably 

 Pathogenic." 



(c) Aspergillus nicer.— This has brown or black conidia. 



(d) Aspergillus nidulans.— This has bright green conidia, branched 

 sterigmata and pink perithecia. 



(e) Aspergillus flavus.— This has yellowish-green conidia and a rough 

 stalk. 



(f ) Aspergillus candiuus.— This is colorless. 



2. PENICILLIUM 



There is no enlargement of the conidiophore to form a vesicle. Instead, 

 the sterigmata appear directly on the stalk. They have many variations. 

 There may be only primary sterigmata from which chains of spores are 

 formed, or the sterigmata may branch once or twice. Another variation is 

 the development of aberrant sterigmata, which results in an asymmetrical 

 appearance. 



3. MUCOR 



These organisms are commonly found as bread molds. The mycelium is 

 abundant, coarse and nonseptate. The typical finding is a sporangium 

 which is a black or brown rounded receptacle situated at a terminal por- 

 tion of a hypha. 



4. ALTERNARIA (MACROSPORIUM) 



The multichambered pyriform spores are present in continuity with the 

 \ egetative hyphae. There may or may not be mycelium between the spores. 

 The color of the spores may be dark olive, green or brown. 



5. HORMODENDRUM 



From the sterigma (stalk) arise spores, which are usually olive-green. 

 Thev are formed from one another in chains, the youngest cell being at the 



