210 DR. LINDSAY ON THE SPERMOGONES AND 
Tribe I. LECANOREI. 
Genus I. LECANORA. 
There is a general resemblance between the spermogones of Lecanora and those of the 
genus Lecidea. Their form is sometimes point-like, as in L. cervina and milvina; occa- 
sionally conoid or papillæform, as in L. atra, sophodes, milvina, and cinerea; sometimes 
larger, more irregular, and wart-like, as in £. ventosa, subfusca, or tartarea. The most 
irregular forms are those which are confluent, as in L. ventosa, atra, and ferruginea. 
The cavity is generally simple and spherical. It is sinuous or compound where the sper- 
mogone is composed, by confluence, of several conceptacles, as in L. ventosa, and some- 
times in, or in some forms of, L. parella, ferruginea, subfusca, and frustulosa. The colour 
is sometimes that of the thallus, in which ease they may resemble nascent apothecia, as 
in the irregular tubercles of L. tartarea. They are whitish in L. subfusca var. epibrya, 
and in tuberculosa ; black in atra, sophodes, and cinerea ; orange-yellow or red in L. auran- 
tiaca, ferruginea, and callopisma ; brown in L. Lallavei and milvina. In L. tuberculosa 
whitish ones are pulverulent, as in Lecidea abietina. The envelope is thickish, and 
generally brown. The internal tissue (as seen on transverse section) is dense, hazy, and 
hygrometric ; it is usually darker in colour than the white medullary tissue of the thallus, 
this distinction of colour being sometimes the only means of recognizing the spermogones 
on section of the thallus, where the ostiole is pale, very minute and imperceptible, as in 
L. parella. In cases where the ostiole is very small and inconspicuous, the spermogones 
are recognizable only on section of the thallus. Sometimes, though pale and semi-pel- 
lucid, the ostiole is large, and easily distinguishable under the lens, when moistened, as in 
L. subfusca or glaucoma. It is brown, large, and irregular, though also semi-pellucid, in 
tartarea, in which species it may also be round, triangular, or chink-like. It is bluish- 
black or black in L. varia and sulphurea, where it is very distinct, from contrast with the 
pale eolour of the thallus. Sometimes it is girt with a pale, tumid, thalline margin, as 
in tartarea and subfusca. In L. torquata this border is subpruinose, as it is in Lecidea 
Jusco-atra, contigua, and other Lecidee. As to site, the spermogones are generally ex- 
ternal to the region occupied by the apothecia. They may be scattered over the whole 
surface, on irregularities of the thallus, or on the granulations of which it is made up. 
Sometimes they are arranged about the zigzag boundary-lines of the thallus, as in JL. 
glaucoma, sulphurea, and sophodes. In L. atra they are sometimes placed at the corners 
of the thalline areolæ, as in Lecidea fusco-atra and contigua. In L. cervina they are 
dotted over the thalline scales. Sometimes they are confined to sterile areolæ or scales, 
one or several occurring on each areola, as in L. cinerea. In L. olivacea each spermo- 
gone crowns one of the scales of which the thallus is composed. In Z. parella the sper- 
mogones form greenish dots, seated on the top of thalline isidia. In L. milvina they are 
scattered on the areole. They are frequently wholly ¿mmersed in the thallus, when 
punetiform, as in L. sulphurea, varia, erysibe, olivacea, and sometimes in milvina, in 
which latter case they are also depressed. At other times they are semi-immersed, when 
papillzeform : or they are superficial when tuberculiform or conoid, as in L. atra. When 
immersed their apex is sometimes flat, as in Z. glaucoma and torquata. As to size, the 
