
OF FILAMENTOUS, FRUTICULOSE, AND FOLIACEOUS LICHENS. 191 
FAMILY XII. Parmeuim. 
GENUS I. Sticta, Ach. 
The spermogones in this genus are more or less immersed in the tissue of the 
thallus, their presence being indicated on the surface of the thallus generally by 
a minute, punctiform brown ostiole. This ostiole may be flattened, slightly ele- 
vated, or depressed. It is also frequently seated on the apex of thalline papille, 
varying in size, and which, when confluent, as occasionally happens, may even 
assume the character of large irregular tubercles. Moreover, frequently in the 
same species, and even in the same specimen, the ostiole may be flat, depressed or 
papilleform. Now, it is of importance to bear this in mind, inasmuch as NyLan- 
DER describes the spermogones of Sticta as always and altogether immersed, 
and this he regards as a distinguishing character of Sticta, as contrasted with 
his genus Ricasolia, whose spermogones are mammillar tubercles. This I do not 
regard as a good, because by no means a constant, character. In regard to their 
spermogones, as to their thallus and apothecia, Sticta and Aicasolia pass into 
each other, and are inseparably united and intermingled. The division is purely 
arbitrary, and hence unnatural. In both genera the spermatia and sterigmata are 
precisely the same. In few species of either genus do the spermogones always 
maintain the same unvarying character. Though normally or generally puncti- 
form, they may be occasionally papilleeform; and though usually papilleform, 
they may be sometimes punctiform. Hence, I will speak of a form of spermo- 
gone predominating in certain species. With this explanation or reservation, I 
would say that the punctiform spermogone predominates in S. pulmonacea, syl- 
vatica, linearis, carpoloma, aurata, orgymea, faveolata, filicina ; the papilleeform in 
S. endochrysa, obvoluta, argyracea, damecornis, xanthosticta, cinereo-glauca, glabra, 
Freycinein, and laciniata: while the spermogones may be either flat, depressed 
or papilleform in S. flavicans, DUrvillei, and flabellata. Yn S. obvoluta, and 
damecornis, the papille are sometimes large, with a conspicuous brown ostiole ; 
and they then resemble nascent or young apothecia. ‘The spermogones of Sticta 
are sometimes easily seen on the beautiful yellow or glaucous thallus, from the 
contrast with the deep-brown colour of the largish ostiole. This ostiole, however, 
in the young and mature state, is generally more or less minute; and, added to its 
minute size, it is sometimes of so pale a colour that it is apt to be overlooked. 
Sometimes it is large and disk-like, flat or depressed, especially when crowning large 
papillz. With age, it expands, and when the nucleus or body of the spermogone 
falls out, as frequently happens, it may become saucer-shaped, with ragged, gene- 
rally thickened and dark-coloured, margins. In this state, the ostioles of old 
Spermogones sometimes have the aspect of black rings or disks, as occasionally 
in S. aurata. However large or small the ostiole or external protuberance of the 
