SCLEROTINIA. 261 



Woronin ^ in Finland, and later by Ludwig in the Erz mountains. 

 The ascocarp developed from the sclerotia has no rhizoids. The 

 ascospores infect leaves, and there the conidia are produced. 



Scl. padi Wor. Causes mummification of the fruits of 

 Prunus Padiis. Woronin regards Monilia Linhartiana Sacc. as 

 belonging to this Sclerotinia. 



Woronin also considers the conidial form Monilia cinerea 

 as related to the mummified fruits of cherry. 



Ovidaria nelans on Mespilus is probably also a form of some Sclerotinia. 



A Sclerotinia occurring on Cotoneaster nigra produces mummification of 

 the fruit, and forms conidia on the surface. 



Monilia fructigena of the apple, pear, quince, plum, peach, etc., is in 

 all likelihood a form of some Sclerotinia, although the ascus-form is still 

 unknown (see also " Fungi imperfecti "). 



Scl. betulae Wor. (U.S. America). This sclerotium of the 

 birch-fruit was discovered by and briefly described by Woronin 

 in 1888. Nawaschin^ has recently re-investigated it, and 

 named it the "birch-catkin disease." It is found on the green 

 catkins in June. The fruits containing sclerotia are obcordate 

 in shape, instead of the normal elliptical form with both ends 

 acute ; the wings are similar to those of healthy seeds. The 

 sclerotium is composed of a very hard white pseudoparenchyma, 

 which passes in the form of a horse-shoe round one side of the 

 apex of the fruit (Fig. 139). The outer layer is black and very 

 firm. Sclerotia placed on moist sand produced ascocarps at the 

 beginning of May. Development in the open also takes place 

 about this time. In the birch forests near St. Petersburg this 

 disease is common, and birch-catkins containing sclerotia may 

 be found abundantly amongst fallen leaves about the month of 

 May. From each sclerotium there are produced one or two 

 ascocarps, with rhizoids and stalks of a length varying with 

 the depth of dead leaves on the ground. The apothecia 

 are at first funnel-shaped, but later became saucer-shaped 

 and l-4mm. broad, with a golden or fleshy colour. The asci 

 contain eight spores which are forcibly ejaculated, and if a 

 handful of damp birch leaf-mould is thrown up into the air 



1 Woronin, Berichte d. deutsch. botan. Ges., 1891; also Mim. de I'acad. imp. 

 d. sci. de St. Petersburg, 1895. With five plates. 



^Nawasohin, Sclerotinia betvlae, Wor. Russian brochure with four coloured 

 plates, 1893. 



