OIDIUM 



1093 



Genus Oidium Link, 1809, emendavit Pinoy. 



Definition.— Oosporacese with hyphse terminating in chains of 

 spores. Hyphse long and branched. Sporophores simple, septate, 

 often without disjunction apparatus. Do not produce gas in carbo- 

 hydrates. 



Type Speeies,— Oidium lactis Link, 1809. 



Remarks.— Pinoy has adjusted this genus, so that now it contains 

 human parasites, which are : — ■ 



These fungi may be differentiated as follows : — ■ 



A. Only produces slight acidity, and only at times, in glucose; cultures 



white — Lactis. 



B. Produce acidity in several carbohydrates: — 



I. No acidity in glucose; culture white and hairy — -Matalense. 

 II. Acidity in glucose 



{a) No acidity in mannitol: — 



Mycelial spores, roundish or oval. Typical colonies con- 

 voluted — Rotundatum . 

 [h] Acidity in mannitol : — - 



Mycelial spores, quadrangular. Typical colonies asteroid 

 — A steroides. 



Definition." — Oidium found in milk, in which it produces acid and 

 clot. Grows easily on ordinary culture media, producing white 

 colonies. It does not form gas in carbohydrate media, and only 

 slight acidity at times in glucose. 



Oidium lactis Link, 1809. 

 Oidium rotundatum Castellani, 1911. 

 Oidium asteroides Castellani, 1914. 

 Oidium matalense Castellani, 1915. 



Fig. 57 1 . — Oidium rotundatum 

 Castellani. Fresh Pre- 

 paration. 



Fig, 572. — -Oidium asteroides 

 Castellani. Fresh Prepara- 

 tion. 



Oidium lactis Link, 1809. 



