. Les fleuristes [microforme] examen. La floriculture. 18 La revue^ Fleuristes MabCh 13, 1919. Comme il a été trouvé pour être vrai de nombreux champignons, ce champignon est réalisée grâce à l'hiver sur les feuilles tombées dans le stade qui ascosporic élabore le printemps suivant. Bien qu'à maturité les asques dis- exposé les spores par l'intermédiaire d'un pore apical formé par la rupture de la paroi, les spores sont apparemment pas déchargée avec violence. Wolf précise qu'ils ne s'empilent dans un tas blanchâtre dans l'ouvert périthèce. La façon qu'ils atteignent l'évolution de la part de l'usine n'a jamais été clairement déterminé, mais c'est pb

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. Florists' review [microform]. Floriculture. 18 The Florists^ Review MabCh 13, 1919. as has been found to be true of many fungi, this fungus is carried through the winter on fallen leaves in which the ascosporic stage develops the following spring. Although when mature the asci dis- charge the spores through an apical pore formed by the rupture of the wall, the spores are apparently not discharged with violence. Wolf states that they merely pile up in a whitish heap in the opened perithecium. How they reach the unfolding leaves of the plant has never been definitely determined, but it is probable that insects, splashing rain and possibly the wind play an important part. Man, in cultivating, may also serve as an agent of inoculation. The maturity of the ascospores and the occurrence of rainy periods when the spores are mature are factors gov- erning spore discharge. The ascospores which are probably distributed during a rainy period re- quire moisture to germinate and pene- trate the host. They germinate within twenty-four hours. Wolf found the pe- riod of incubation to be about ten days, small black areas being evident May 7 from inoculations made April 27. Infection occurs by the entrance of the germ-tube directly through the cu- ticle of the leaf. The resulting mycel- ium remains for some time immediately beneath the cuticle, later penetrating the tissues below, first filling the epi- dermal cells and only in advanced stages of the disease penetrating the meso- phyll. The black appearance of the spots is not due to the fungus, which is almost colorless, but to the disinte- gration of the cells below the spot. EnyiToiuiiental Relations. Temperature and especially moisture are factors which may influence the se- verity of the disease by their effect on the parasite and the host. It is a matter of common observation that greenhouse roses are more subject to this disease in the spring and autumn, when extremes of temperature are most likely to occur. Frequent rains a

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