Leptostroma.] rUNGl. 297 



On leaves and calms of grasses. Spring. — Forming little, round, very 

 flat black spots, with a central umbo of a close radiating fibrous struc- 

 ture, like that oi Pt/renula fiiffrescens, Ach. 



70. PiiosTHiMiUM. Kunze, Prosthemium. 



Peritheckim innate, orbicular, very much depressed, contain- 

 ing an entangled mass of cylindrical, articulated filaments ; to 

 ^vhich are attached, two or three together, in radiating fascicles, 

 the fusiform sej)tate sporidia. — Named from T^oods/xa, the sporidia 

 being as it were aj^plied to the Jiiamenis. 



1. P. hetidinum, Kunz. (^Birch-tree ProsiJiemiam), — Kunzc 

 JMtjc. Ilef. \.p. 17. t. I./. 10. Ft. Si/st. jSIijc. v. 3. ;?. 484. 



On branches of Betula alba. Milton, ><'orths. 3Iessrs. Henderson 

 Sf Berhelei/. — This genus is to StUbospora what Cytispora is to 

 Ncemaspora. I find iho perit/iecia presenting, in a vertical section, an 

 elliptic outline, not merely covering the sporidia and filaments, but sur- 

 rounding them on all sides, and the sporidia longer than in the figure 

 quoted al^vc. Nothing can be more striking than their exact resem- 

 blance to those of some Cordomycetes. I possess a fungus of a somewhat 

 similar structure, on Lime branches, but differing in having the stratum 

 to which the sporidia are attached scarcely filamentous, and the sporidia 

 imiseptate. As I have only found this once, and very sparinglv, I 

 leave it for future investigation. 



71. Leptostroma. Fr. Leptostroma. 



Pcrithecium innate, subumbonate in the centre, dimidiate, at 

 length falling off and leaving a very thin disc. — Name, Xsttct', 

 ihiv, and e-T-io/xa, a layer. 



1. L. caricinum, Fv. (Sedge Leptostroma) ; subrotund unequal 

 thin opaque, entirely falling oft' and leaving a brown spot. Fr. 

 Obs. '2. t. 1 .f. 4. Scler. Suec. n. 17G. Syst. JSIyc. v, 2. p. 598. 



On leaves of various Cariccs. About Edinburgh, Dr. Grevillc. — 

 The perii/iccium is extremely tliin, and it leaves, when fallen off, a i)ale 

 brown spot surrounded by a little raised line. Other less perfectly 

 defined sj)ots, but of the same size, accomj)any the |)erfect ])lant, which 

 are either old worn indiviiluals, or an imj)crfectly developed state ; 

 occasionally in the centre of these there is a white I'ule spot. 



2. L. Jilicl/iinn, Fr. {Fan-stem Lrptostroma) ; elongated 

 irregular even black marked when perfect with an elevated 

 longitudinal rib, at length separating entirely at the base. Fr. 

 Obs. 1. p. 197. Slier. ^Suec. ! 7i. 65. — Xyloma striaformisy 

 Moug. H^ Nest. ! v. 47G.-^Sph. Ptcridis, Sow. ! t. 394./ 10. 



On tlead stems of Ptcris afpidiua. Not uncommon. — It recpiires 

 rare to distinguish jhis plant accurately. Scbrotium l^firidis, Moug. 

 & Nest. n. Ol'.i, which occurs on almost every fern-stem, generally 

 accompanies it, but whellur it is the \oung or imperftctly develojcd 

 plant or a distinct species is very doubtfiid. L.jdicinum often a^snmL■s 

 the form of an Ilysttrium and may almost always be distinguished by 

 the rib which runs down the centre. I have found it in winter dis- 



