256 ASCOMYCETES. 



and striped, the margin being fibrous. The asci contain four 

 to eight spores. The spores are generally ovoid or spindle- 

 shaped, at first unicellular, but divided later into two to four 

 cells by means of cross walls. The colourless paraphyses 

 have thickened club-like apices. 



Belionella Dehnii (Rabh.).i This parasite covers stems 

 and leaves of Potentilla norvegica, and is distinguished by its 

 sharp, spindle-shaped, bicellular spores. 



HELOTIEAE. 



The apothecia are generally quite superficial ; less commonly 

 they are at first embedded, and emerge later; or they may 

 develop from a sclerotium. In form they are spherical, cup- 

 shaped, or top-shaped, and a stalk of some kind is generally 

 present. On opening, they form a cup or flat plate, on which 

 the hymenium lies exposed ; the cup is soft or waxy, and 

 enclosed in a delicate wall, which is externally either smooth 

 or hairy. The sporocarps consist of a pseudoprosenchyma 

 {after Rehm). 



Sclerotinia. 



The sclerotia ^ give rise to smooth-stalked ascocarps with the 

 form of beakers, funnels, or saucers. The stalks often produce 

 rhizoids. The asci contain eight unicellular hyaline spores, 

 elliptical or spindle-shaped, and of equal or unequal sizes. 

 The paraphyses are thread-like. In several families conidia are 

 formed before the sclerotia. Some forms are heteroeeious. Most 

 of the species are parasitic on plants. 



The Sclerotium diseases of the Vaccinieae.^ 



These are a well-known group of sclerotium diseases, and 

 amongst them the following have been named as species. 



Sclerotinia vaccinii Wor. {Sd. Urnula Weinm.). The 

 sclerotium disease of the cowberry. The young shoots and 



'Figures in Hedioigia, 1881, 



''Literature: De Eary, "Uebereiuige Sclerotien u. Solerotienkrankheiten," 

 Botan. Zeitung, 1886; a,\so Morphology and Biology of the Fungi, English edition. 



Brefeld, SchimmelpUze, Heft. iv. u. x., and Botan. Zeitung, 1876. 



Saocardo, Sylloge, Vol. viii. 



' Woronin, Jlf^m. deVacadem. im.p6r. d. sci. d. St. Petersburg, vn. Ser., t. 36, 1888 

 •{with ten plates) ; also Berichte d. deutsch. botan. Ges., 1894. 



