274 DR. LINDSAY ON THE SPERMOGONES AND 
larger in all dimensions than in the two others. The smaller ones are sometimes straight. 
All forms are borne on very short, linear, simple but indistinct sterigmata. 
Specimen 21. Var. siderella. In the Kew herb. sub O. siderella. Spermogones are 
abundant, scattered among the lirellæ as small, immersed, punctiform bodies, brown 
when moistened, black when dry. The spermatia are linear (or cylindrical), slightly 
curved, zogo X 55460 on short, simple sterigmata. 
Mudd apparently (Br. Lich. p. 233) institutes a distinction between the spermogones 
of var. stenocarpa and of var. siderella, Ach. The crescent-shaped spermatia described by 
Körber (Syst. Lich. Germ. p. 284) under O. herpetica, are probably referable to O. vulgata. 
Those of herpetica, though occasionally slightly curved, are always cylindrical—that is, 
of equal width throughout, with obtuse or rounded ends. Neither are they of the same 
length as the crescentic spermatia of vulgata. 
The Pyrenothea lutea of Leighton (Angioc. Lich. p. 68, pl. 29. fig. 4) quite corresponds 
with the spermogones of O. vulgata as above described. He himself says, “ Intermixed 
with this grew Opegrapha . . ... in which the sporidia were in asci 8, fusiform, 4-sep- 
tate." "The spermatia (supposed sporidia) are “not in asci, free, curved, of a linear 
shape, finely tapered at each extremity, pale yellow." The spermogones (supposed spo- 
ridiiferous apothecia or perithecia) are * very numerous and crowded, generally one on 
each thalline areole, dark brown, hemispherical, depressed. Perithecium dimidiate, thick 
and clumsy. Nucleus white when moistened.” 
A form of Spiloma nigrum, Turn. & Borr. (var. y), in the Kew herb. is apparently merely 
a degenerate state of O. vulgata; a few lirellæ as well as spermogones of that Opegrapha 
can be detected. The Spiloma is also partly referable to Spilomium graphideorum, 
Nyl. (Exs. No. 72; Lindsay, * Observations on New Lichenicolous Microfungi,” Trans. 
Royal Soc. of Edinb. vol. xxv. p. 543, pl. 24. fig. 11), a minute Uredinous fungus, 
which grows upon and destroys the apothecia of Opegrapha lyncea, Borr., and other 
Graphidei. 
The spermogones of O. vulgata also constitute, in part at least, several other Pyreno- 
thee, e. g. P. stictica, Fr., P. vermicellifera, Fr., and P. niveo-atra, Borr. 
Species 2. O. HERPETICA, Ach. 
Specimen 1. Var. rufescens, Pers., Airyholme Wood, Cleveland: Leight. Exs. No. 221, 
sub var. rubella, f. simplex; referred to var. rufescens by Mudd (Br. Lich. p. 235). The 
spermogones, which are scattered among the lirelle as very minute brown points, are 
scarcely visible on the olive-green thallus even after moisture. They are quite round, 
immersed, with an envelope of deepish-brown cellular tissue. Spermatia are short, linear, 
usually straight, but sometimes very slightly curved, on short, simple sterigmata. 
Specimen 2. Var. rufescens. On beech, Switzerland: Scher. Exs. No. 95, sub O. 
rufescens, var. rubella; referred to var. rufescens by Mudd (Br. Lich. p. 235). Spermo- 
gones are brown and punctiform, scattered about the lirellse, so minute that they are 
with great difficulty recognizable, even under moisture. Spermatia are short, linear, or 
linear-oblong, straight; the sterigmata simple, but longish and subcolumnar. Basal 
cellular tissue deep brown. 
