232 BOTANICAL GAZETTE [September 



the margin at length breaking through the epidermis and here and 

 there becoming connected with the margin of the shield. Fruit 

 bodies closed at first, later opening by the rupturing of the shield 

 together with the upper part of the apothecium in an irregularly 

 stellate manner from the center. Asci oblong or subclavate, 

 narrowed abruptly above, 70-80X15 A*, 8-spored; paraphyses 

 slender, enlarged abruptly at the tip, often i-septate. Spores 

 oblong-elliptical, hyaline, unequally 2-celled,. constricted at the 

 septum, 20-25X5-6/*; upper cell somewhat larger, cells usually 

 guttulate. 



Conidial stage.— Spots epiphyllous, large, dark brown or blackish, 

 with an irregular radiating border, when numerous becoming 

 confluent and sometimes involving the entire leaf. Mycelial 

 strands composed of several filaments, at first hyaline, forming a 

 subcuticular network. Internal mycelium connected through the 

 epidermis with subcuticular mycelium. Acervuli subcutaneous, 

 covered at first by the cuticle which ruptures irregularly; conidia 

 2-celled, often deeply constricted, straight or subfalcate, 18-25X 

 5-6 m, hyaline and guttulate. 



Conidial stage appearing on rose leaves in summer and autumn often 

 causing defoliation of the plants. Ascigerous stage appearing in the spring 

 on fallen leaves which have remained on the ground. 



Peritheciis epiphyllis, globosis v. disciformibus, 100-250 /x diam.; scutulo 

 atro-brunneolo, subcutaneo, mycelio reticulato insidiente, orbiculare, margine 

 plus minusve radioso. Apothecio primo epidermide tecto, demum margine 

 scutuli adjuncto, in centra irregulari-stellato dehiscente. Ascis oblongis vel 

 subclavatis, supra obtuse angustatis, 70-80X15 ^ octosporis; paraphysibus 

 filiformibus, apice incrassatis, interdum i-septatis; sporidiis oblongo-ellipticis, 

 inaequaliter bicellularibus, ad septa constrictis, guttulatis, hyalinis, 20-25X5" 

 6 fx. 



Hab. in foliis dejectis Rosae sp. 



Status conidicus: Maculis epiphyllis, atro-brunneis vel purpurascentibus, 

 fibrillis e centro radian tibus, albido-arachnoideis; acervulis subcutaneis, 

 sparsis, nigricantibus; conidiis constricto, i-septatis, guttulatis, hyalinis, 



18-25X5-6 /X. 



Hab. in foliis vivis Rosae sp. 



Susceptibility of the host 



This disease occurs on nearly all the cultivated varieties of 

 roses both out of doors and in the greenhouse. Briosi and 

 Cavara note that only four varieties, Rosa hybrida var. Belle 



