542 DR LAUDER LINDSAY ON NEW LICHENICOLOUS MICRO-FUNGI. 



thayock Woods, Perth, June 1856, W. L. L. Thallus consists of a series of 

 minute, irregular pulvinuli, of a buff colour, on which the black perithecia of the 

 parasite are conspicuous by contrast. This contrast is rendered greater, however, 

 by the circumstance that the patches of thallus occupied by the parasite are 

 lighter in colour than the rest of its surface. The parasitic perithecia are 

 extremely minute and punctiform, so closely scattered as to give the thallus the 

 appearance of being covered with granules of coal-dust. Sometimes they are so 

 numerous and so closely aggregated as to become confluent in very irregular 

 patches. Under moisture, the single perithecia assume a papillaeform character. 

 The Microthelia cannot be confounded with the young apothecia of the Bceomyces. 

 which are brown, and much larger in almost all stages of growth. Sporidia 

 of the Microthelia dark brown, oval ; 3-septate ; frequently or generally con- 

 stricted at or opposite the septa. The thallus of the same Bceomyces, as well 

 as that of B. roseus, Pers., is affected by Nesolechia ericetorum, Fw. (Korb., 

 Parerga, p. 461), whose sporidia are minute, ellipsoid, sub-bacillar, simple, 

 and hyaline. On B. rufus also occur Lecidea parasitica, Flk., L. scabrosa. 

 Ach., L. inquinans, Tul., and L. arenicola, Nyl., as well as Thelocarpon epithal- 

 linum, Leight. * 



9. M. atricola. Parasitic on thallus of Lecanora atra, Ach., on red sandstone, 

 Derriquin, County Kerry, Taylor in Herb. Moore, Dublin; associated with 

 Lecanora periclea, Ach. (= var. of L. sophodes, Ach.). The parasite has the 

 facies of a Verrucaria or Endococcus ; its perithecia being minute, distinct, black 

 cones, with sometimes a flattish or depressed apex ; becoming occasionally 

 irregular in form ; seated on, scarcely in, the thallus of the host. Asci 0020'' 

 long, -00066'' broad ; crowded with innumerable sporidia. Sporidia spherical, 

 simple, deep brown, about 000083'' in diameter; resembling those of many 

 Calicia. 



L. atra, on the Continent,! is occasionally the seat of another parasitic fungus, 

 Gassicurtia silacea, Fee (Nylander, Prod. p. 91 ; Lich. Parisienses, No. 150), 

 which either affects the thallus or apothecia, sometimes occupying the place of the 

 latter. The parasite consists of black filaments, forming in the aggregate brush-like 

 masses, similar to the apothecium of Sphwrophoron in some of its old stages of 

 growth; it has a Spilomatic or glomeruliform facies. In the only authentic 

 specimen I have examined (in Nylander's Herb. Lich. Paris., No. 150 ; on stones in 

 Forest of Fontainebleau), the thallus is sterile, consisting of a series of cushion- 

 like areolae, more or less scattered, seldom closely aggregated. Some of these 

 white tartareous verrucse are occupied by the parasite, which is very black, 

 irregular in form, and easily distinguishable under the lens from the apothecia of the 

 Lecanora ; surface generally more or less subgranular. The spores are deep brown ; 



* Vide Paper on " Parasitic Micro-Lichens" (antea eitat.). 



t And in New Zealand ; Lindsay, " Obs. on N. Z. Lichens," p. 540. 



