PHYTOPHTHORA 



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Phytophthora omnivora, De Bary (= Phytophthora cactorum, 

 Schrot). Hartig has paid special attention to this fungus, 

 more especially as a parasite attacking beech seedlings, 

 although as one of its specific names indicates, it also attacks 

 other plants, more especially in the seedling stage, among 



Fig. 28. Phytophthora omnivora. A beech seedling 

 attacked by the fungus. The dark portion of the stem 

 below the cotyledons, and the blotches on the cotyledons, 

 are caused by the mycelium present in the tissues. 



which may be mentioned Cactus, Acer, Fraxinus, Eobinia, 

 Fagopyrum, Sempervivum, Clarkia, and various conifers. 



In seedlings, the appearance of dark-coloured blotches on 

 the cotyledons or the primary leaves indicates the presence 

 of the fungus ; dark patches also frequently occur on the stem 

 below the cotyledons, and when this is the case recovery is 



