270 DR. LINDSAY ON THE SPERMOGONES AND 
the plant as a Verrucaria (Engl. Bot. pl. 2622 (1950), fig. 2), Schærer to call it Lecidea 
spherica, and Flotow to constitute it a variety spherica of his Lecidea Draparnaldi. 
According to Mudd (p. 271) the sporidia of L. Hookeri are typically broadly fusiform, 
3-septate, and brown; but their character is very variable and puzzling. According to 
Nylander, however (Prod. p. 139), the sporidia in question are really those of the parasitic 
Spheria, those of the Lecidea being l-septate, though also brown. Both the Lecidea 
and Spheria require re-examination and a clearing up of their very confused synonymy. 
Species 48. L. EPIGÆA, Pers. (Nyl. Prodr. p. 119). 
Specimen 1. Lochnagar, Braemar, Aug. 1856: W. L. L. The spermogones are small, 
black, punctiform or tuberculiform, slightly prominent, scattered one or two on each squa- 
mule of the thallus, as in Z. lugubris*. They are, however, either old or degenerate, con- 
taining no free spermatia. 
Species 49. L. GEOGRAPHICA, L. (=Rhizocarpon, Mudd, Br. Lich. p. 221). 
Specimen 1. Var. contigua, Fr. (Mudd, Br. Lich, p. 221): Leighton's Exs. No. 129, 
sub var. alpicola. Associated with, but not necessarily belonging to, this Lecidea, are 
spermogones containing sublinear spermatia, atomic in size, on short, linear sterigmata, 
that branch below as in Ramalina. The cavity of some of the spermogones is filled up 
with a network of anastomosing ramose filaments, thickish, indistinct, sterile, very tor- 
tuous in their outline. 
Tribe III. GRAPHIDEI. 
Genus I. OPEGRAPHA. 
As a general rule its spermogones resemble those of Verrucaria in being variously 
papilleform or punctiform, chiefly or wholly immersed. Usually they are very minute, 
and with diffieulty discoverable: sometimes they are comparatively large and distinct, 
as in vulgata. Their depth is 355. their breadth 545 to 355, in varia. Generally their 
colour is black, though exceptionally it is brown. They are, therefore, distinct by con- 
irast of colour where the thallus is whitish or greyish, as it frequently is. "Their en- 
velope consists of a deep-brown tissue, composed of roundish cellules. The cavity is 
invariably simple. They are usually scattered irregularly over the thallus and amongst 
the apothecia—sometimes, however, outside the region occupied by the apothecia, as in 
vulgata, in which species spermogones are more easily and constantly found than in any 
other Opegrapha. The spermatia are usually straight and linear, or ellipsoid as in varia. 
In a few cases, as in vulgata, they are curved, either with acute ends and a thicker centre 
or body (crescent-shaped), or of equal width throughout, and with blunt or rounded tips. 
Both these forms of curved spermatia occur in the same species, vulgata. These curved 
forms are also generally the longest, varying in vulgata from 5355 to suso. In ker- 
petica the spermatia are 54455 long, in varia from g45g to 55450. Their breadth is 
* As described and figured in my paper * On the Structure of Lecidea lugubris, Smrf.,” Quart. Journal of Micro- 
scopical Seience, p. 8, pl. xi. figs. 1, 2, 3, 4, 6. 
