298 DR. LINDSAY ON THE SPERMOGONES AND 
semble the apothecia, than which, however, they are much smaller. Still they are 
sufficiently large to be comparatively conspieuous or easily made out under the lens. 
Spermatia are 35500 X 20.000 apparently on short, simple sterigmata. 
Species 14. V. NIGRESCENS, Pers. 
Specimen 1. On slate in walls, near Cork: Carroll. Spermogones are abundant about 
the boundary-line of the thallus, as very small conceptacles with compound cavity, and 
thiek walls of deep-brown cellular tissue. They resemble externally the apothecia, than 
which they are much smaller; and they are scarcely to be distinguished therefrom, even 
under the lens. Spermatia are rod-shaped, 4455 X 55-460: on thickish, irregular arthro- 
sterigmata. 
Species 15. V. FUSCELLA, Turn. (Mudd, Br. Lich. p. 288). 
Specimen 1. On limestone, Dunkerron, co. Kerry: Taylor in herb. Dr. Moore. Asso- 
ciated with Opegrapha rupestris, Pers. The thallus is studded over with the black, sub- 
prominent perithecia of Y. gemmifera, of which one usually occurs on each of the central 
areole. Sporidia 305 X sooo: These parasitic perithecia are apt to be mistaken for 
either young apothecia of Y. fuscella, or for its spermogones. 
Species 16. V. Le1IGHTONIL, Hepp. 
Specimen 1. Var. wmbrina, Leight. (Mudd, Brit. Lich. p. 287), Diganwy, near Conway, 
Caernarvonshire: Leight. Exs. No. 101, sub Y. umbrina, Ach.; associated with Y. chlo- 
rotica, Ach. Two forms of pycnide occur, which may be respectively referable to Y. 
Leightonii and Y. chlorotica. Pycnides of the one form are scattered among the apo- 
thecia, on the second specimen from the right hand in my copy. The stylospores are 
oval, but somewhat irregular in form, 35455 to 1055 X sooo: Seated on basidia that are 
simple, filiform, flexuose, thickish and hyaline, about 177 long. Pycnides of the other 
form are undistinguishable, externally, from the apothecia among which they are scattered. 
The stylospores are oblong or ellipsoid, generally 1-septate, very variable as to size, 
to 5555 long, and 5565 to 13505 broad. 
1 
2500 
Species 17. V. PYRENOPHORA, Ach. (= Thelidium, Mudd, Br. Lich. p. 294). 
Specimen 1. On sandstone, Whitecliffe rocks, near Ludlow, Shropshire: Leight. Exs. 
No. 189. Spermogones are very sparingly distributed over the subtartareous, dark olive, 
areolate thallus, as minute black points. Spermatia rod-shaped, on indistinct, simple 
sterigmata; only a few spermatia were met with in one of many examinations. 
Species 18. V. GAnovAGLII, Mont. (= Dermatocarpon, Mudd, Br. Lich. p. 270). 
Specimen 1. Under the name Endocarpon rufescens, Ach., and so labelled by Ny- 
lander in the Kew herb., are two specimens of this lichen, one from Germany, the other 
from. Switzerland, both abundantly spermogoniferous, and containing large, muriform, 
colourless sporidia, two in each ascus. In the German specimen, the spermogones cover 
