ASCOMYCETES EUASCI EXOASCUS 



253 



they grow and spread out to the surface, forming a single layer of cells, each 

 cell swells, the cuticle becomes ruptured and a palisade-like layer of asci is 

 formed. There are eight ascospores in each ascus which escape by means of an 

 opening at the tip. The ascospores of Taphrina frequently germinate in the as- 

 cus, budding like yeast and in this budding condition they produce a small amount 

 of alcohol. Another troublesome species is the Peach Curl (Exoascus deformans) 

 which occurs on the young leaves of peaches. The E. Cerasi is another destruc- 

 tive species producing the "Witches Brooms" of the cherry Prunus Cerasus. 

 The E. BctuHnus produces the "Witches Broom" in the Birches. 



PEZIZINEAE, HELVELLINEAE, TUBERINEAE, PHACIDIINEAE 



Mycelium well developed; asci borne upon large fruiting bodies and a 

 continuous hymenium consisting of the asci, sterile threads, the paraphyses. 

 Contains a number of common cup fungi like the Pesiza, Morchella esculenta, 

 and Hellvella. A Sclerotinia produces a disease on red mangolds, beans, and 

 hemp ; Sclerotinia also occurs upon clover and the common brown plum rot, 

 (Sclerotinia). Helvetia suspecta with a reddish brown pileus and a dirty flesh 

 colored stalk is suspected of being poisonous. It has a nauseous, sweetish 

 taste, and produces hellvellic acid, a hemolytic, or blood destroying substance. 

 The Gyromitra esculenta also produces helvellic acid and is regarded as 

 poisonous. It owes its toxicity to the blood making properties. The Hellvellas, 

 Morels, and Sclerotinia belong to the family, Hehellaceac. Tuber produces 

 tuber like bodies found in the soil. The organism is parasitic on trees. The 

 fruiting bodies are enclosed by a peridium which consists of corrugated, smooth, 

 or wart-like excrescences. The hyphae are compact. The ascospores occur in 

 winding passages in the interior. Some of the Hellvellas and Morels are edible. 

 The truffle (Tuber aestivum) of the family Eutuberaceae are edible. 



The family Phacidiaceae, contains one important parasite of the alfalfa, 

 the Pliacidium Mcdicaginis. The diseased leaves turn yellow and soon fall. 

 The yellow leaf, or in some cases the green leaves, contain the small blackish 

 or brownish specks usually upon the upper side of the leaf, the injury extend- 



\ 



Fig. 80. Enlarged plum branches. Exoascus communis on Prunus maritima, projecting 

 beyond the mass are the asci, some of which contain the spherical ascospores. After At- 

 kinson. 



