EXOBASIDIUM 399 



club becomes branched, or may be divided into numerous 

 branches. 



Beetroot rot. Prillieux calls attention to a disease said to 

 be very destructive to beetroot in Spain. The mycelium 

 covering diseased beetroot received from Spain was found 

 by Prillieux to attack and rapidly destroy sound beetroots 

 and carrots when infected with it. The mode of action of 

 the fungus was identical with that of the species of Sclerotinia. 

 Those portions of beetroot attacked by the mycelium of the 

 parasite contained numerous minute sclerotia, known at one 

 time as Sclerotium semen. This sclerotium is known to 

 belong to Typhula variabilis (Riess.). The Typhula was not 

 met with on the beetroot material, hence it is not absolutely 

 certain that T. variabilis is the cause of the injury, as other 

 species of Typhula also produce somewhat similar sclerotia. 



The sclerotium is about 2 mm. diameter, white at first, 

 gradually changing to brown, circular or oval, depressed, 

 resembling a seed, hence the specific name when it was con- 

 sidered as a distinct species. Common on dead leaves, more 

 especially those of poplar, when lying in heaps in a damp 

 place. In course of time the sclerotium produces a slender, 

 whitish, slightly club-shaped body 1-5-3 cm. high. Spores 

 subcylindrical, ends rounded, hyaline, 6-7 X 2 '5-3 /*. 



Prillieux, Malad. des Platites Agric, 1, p. 304 (1895). 



EXOBASIDIACEAE 



The most primite group of the Basidiomycetes. All the 

 species are obligate parasites ; the mycelium is immersed in 

 the substance of the host, the basidia bursting through the 

 epidermis. 



Mostly parasitic on leaves of plants belonging to the 

 Ericaceae more especially, analogous in habit with the 

 Exoascaceae, belonging to the Ascomycetes. 



EXOBASIDIUM (Woronin) 



Parasitic on living plants, more especially the leaves. 

 Forming galls or blisters that usually become red. Basidia 

 bearing a variable number of sterigmata; spores elongated, 

 continuous, hyaline. Conidia are present in some species. 



