252 | DR. LINDSAY ON THE SPERMOGONES AND 
sometimes proliferous, bearing on their obsolete disks new (young) ones. The spermogones 
are black dots, scattered about the black hypothalline boundary-line of the white thallus. 
The spermatia are straight rods, about 3555 X so;$vo. Sometimes twice as long when 
attached as when free. Sterigmata consist of a few very irregular articulations, mea- 
suring, with attached spermatia, 4557 to zago- Basal cellular tissue deep bluish-brown. 
Specimen 5. On holly, Purple Mountain, Killarney: Carroll, Mar. 1858. Associated 
with Verrucaria epidermidis. On one specimen are scattered, about the apothecia, nu- 
merous microscopic, black, punctiform pyenides, having a simple cavity and a brownish 
cellular envelope. The stylospores are linear, oblong, very pale olive, straight, or very 
slightly curved, about 7757 long, and 55:555 broad, borne on short simple basidia. 
Specimen 6. On bark, Kildale, Cleveland, Yorkshire: Leight. Exs. No. 180. Asso- 
ciated with Lecanora subfusca. A few spermogones occur as black points, seated on the 
small thalline scales, about the black zigzag boundary-line which separates the thallus of 
the Lecidea from that of the Lecanora. Spermatia abundant, rod-shaped. Sterigmata 
longish, delicate, consisting of a few elongated, sublinear articulations. 
Specimen 7. Var. saprophila, Ach. (Mudd, Brit. Lich. p. 217). On old tree-trunks, 
Switzerland: Hepp Exs. No. 150, sub LZ. punctata, var. saprophila. Spermogones are 
plentiful as small black dots, scattered among the apothecia, perched on the thin white 
scales that compose the thallus. Spermatia rod-shaped, about 5555 X 35000, On arthro- 
sterigmata, which are composed of numerous, short, broadish articulations. 
Species 16. L. MYRIOCARPA, DC. (Mudd, Brit. Lich. p. 217). 
Specimen 1. On basalt, Cliffrigg, Cleveland, Yorkshire: Leight. Exs. No. 181. "The 
spermogones are very minute black dots, scattered among the apothecia, but with the, 
greatest diffieulty detected. The spermatia and sterigmata are those of Z. parasema. 
Mudd's description (in 1861) agrees with my observation in 1858; and if it is a constant 
character in myriocarpa that its spermatia are vermiform and its sterigmata simple, 1 
quite agree with him in separating it from disciformis, to which, by some authors, it has 
hitherto been referred as a variety. Nylander, however, in his * Prodromus’ (pp. 126 
and 141) places myriocarpa in that section of the Lecidee which has **Spermatia recta 
cylindrica breviuscula vel brevissima oblongo-ellipsoidea ; ” while in his * Lichenes Scan- 
dinaviæ” (p. 237) he arranges it under the “stirps Lecidee disciformis." There is thus 
here a difficulty in classification, which illustrates the artificiality of all systems, whether 
based on individual or collective characters. If myriocarpa is to be classed according 
to its apothecia and sporidia, it stands rightly under or near disciformis ; but if by its 
spermatia and sterigmata, it must rank with the parasema group, which, again, has very 
different sporidia. Another peculiarity of the present specimen is, that there is some- 
times an intimate anatomieal relation between the apothecia and spermogones, so that a 
section of the former includes also a section of the latter. A few athalline apothecia of 
Lecanora polytropa occur parasitically on the thallus of myriocarpa. But, though the 
spermogones now described have the characters of those of that Lecanora, it is impossible 
to regard them as belonging to it rather than to the Lecidea on whose thallus they are 
seated, and with whose apothecia they are so intimately connected. 
