436 Notes on Parasitic Ascoinycetes. — //. [Sess 



it forms shining, black, swollen patches, in which the 

 perithecia are immersed. Fh, trifolii (Pers.) Fckl., on leaves 

 of white Dutch clover {Trifolium repens), is preceded by 

 Polythrincmm trifolii Kunze & Schmidt, its conidial stage. 

 The latter grows on the lower surface of the clover-leaves, in 

 the form of convex cushion-like clusters of hyphas of a dark 

 olive-brown colour. The threads are erect, jointed, constricted 

 at each joint so as to have a beaded appearance, and bear 

 obovate, two - celled, pale - brown conidia. Another very 

 common species, known as Ph. jpodagrarice (Eoth) Karst., 

 occurs on leaves of goutweed, where, in its early condition 

 ( = Septoria podagrarice Lasch), it produces perithecia which 

 emit conidia in such abundance as to form conspicuous whitish 

 blotches on the upper surface of each affected leaf. These 

 perithecia are followed by black clusters of larger rounded 

 granules, apparently immature perithecia of the type of 

 Pliyllachora, but seldom if ever producing perfect asci and 

 spores. Similarly undeveloped perithecia, usually referred to 

 fungi of this genus, occur on leaves of several other umbel- 

 liferous plants. 



Dotliidella hetulina (Fr.) Sacc. forms stromata on leaves of 

 birch. These first appear as blotches on the living leaves, 

 and finally rupture the epiderm. They become shining black, 

 and contain cavities in which the asci are embedded. The 

 spores, which are ripened after the leaves have fallen to the 

 ground, are pale-yellowish in colour, ellipsoid in shape, and 

 divided by a cross septum into two cells. 



The genus Botryosphceria is represented by B, dothidea 

 (Moug. & Fr.) Ces. & De Not., which forms stromata on living 

 bark of stems of wild rose. These appear as conspicuous, 

 slightly convex, black scabs, usually cracked concentrically. 

 The perithecia are immersed in the stroma, and contain asci 

 with hyaline almond-shaped spores. 



Several species of Cucurhitaria are well known as sapro- 

 phytes on branches of laburnum, barberry, and broom. They 

 form black stromata which burst through the bark. The 

 perithecia are partially embedded in the stroma, and the asci 

 contain eight multiseptate spores of the type known as 

 " muriform," — that is, with some of the septa running in the 

 direction of the length of the spore and some of them across 



