19"] WOLF—ACTINONEMA ROSAE 2*1 



o 



and apothecium, the name Diplocarpori* is proposed. The follow- 

 ing description of the genus is given. 



■ 



Diplocarpon, nov. gen. — Fruit bodies formed in connection 

 with an extensive subcuticular mycelium, consisting of a sub- 

 cuticular circular shield with more or less radiate elements espe- 

 cially at the margin, and an innate apothecium. Shield, together 

 with the radiating strands on which it is formed, dark brown, 

 without a central pore. Apothecium at first separate from the 

 shield, only joined here and there by hyphae which pass between 

 the epidermal cells. Apothecium joined with the margin of the 

 shield at maturity. Hymenium covered by the shield and upper 

 part of the apothecium which at maturity rupture in an irregularly 

 stellate manner. Asci oblong to subclavate, 8-spored; paraphyses 

 unbranched; spores elongated, 2-celled, hyaline at maturity. 



A conidial stage of the Actinonema-type occurs in one species. 



Peritheciis scutulum subcutaneum et apothecium innatum constitutis; 

 scutulo mycelio subcutaneo, lato extenso, atro-brunneolo insidiente; margine 

 radialiter diffuso, contextu membraneo, astomate; apothecio innato, primo 

 scutulo separato, maturitate margine adjuncto. Peritheciis centro stellatim 

 laciniato-dehiscentibus; ascis oblongis; paraphysibus simplicibus; sporidiis 

 oblongo-ellipticis, bicellularibus, maturitate hyalinis. 



Actinonema uni speciei cujus statum conidicum sistit. 



Since this study connects for the first time the ascosporic stage 

 with the conidial stage of the black spot of rose leaves, a brief 

 characterization of the species is added: 



Diplocarpon rosae, n.n. 



Syn. Erysiphe radiosum Fr. Observationes Mycologicae. 207. 1824. 

 Asteroma rosae Lib. Mem. Soc. Linn. 5:404-406. 1827. Acti- 

 nonema rosae Fr. Summa. veg. Scand. 424. 1849. Dicoccum rosae 

 Bon. Bot. Zeit. 282. 1853. Marsonia rosae Trail. Fung. Inverar. 



46. 1889. Marsonia rosae Br. and Cav. Funghi parassiti n. 97. 

 1889. 



Ascigerous stage. — Perithecia epiphyllous, spherical to disciform, 

 100-250 /* in diameter; upper part or shield dark brown, subcuticu- 

 lar, formed in conjunction with the radiating strands of mycelium, 

 circular, with a more or less radiating structure toward the margin. 

 Lower part of fruit body disciform, subepidermal, of several layers 

 °f Pseudoparenchyma cells, the outer of which are dark brown, 



28 *"-Mos, "double," Kapirbs, "fruit." 



