
OF FILAMENTOUS, FRUTICULOSE, AND FOLIACEOUS LICHENS. 175 
belonging thereto, though I have occasionally met with sundry parasites closely 
resembling them, and for which they might be mistaken. 
Species 1. SS. saccata, Ach., 
Which grows both in America and Europe. The sterile thallus is sometimes covered 
over with black cones or tubercles, partly immersed, and with a distinct ostiole. 
These may readily be mistaken for spermogones; but their contents at once 
| reveal their true nature. They are found to be perithecia, containing brown 
3-4-septate oblong-oval spores. This is the Sphwria urceolata, ScamRER (in 
Hepp. exs. 475, f. 2), on limestone rocks on the Pilatus, Switzerland; and En- 
docarpon psoromoides, Hoox. and Lreicuton, at least pro parte. This parasite, 
again, is apt to be confounded with Verrucaria psoromia, Nyu., which has simple, 
ellipsoid, colourless spores (Phacopsis psoromoides, HEpr. exs. 475, f.1, Verrucaria, 
Borrer, E. B. 2612, f. 1.) 
Sprcies 2. S. crocea, Ach., 
Which occurs in Europe, America, and frigid or northern Asia. 
Specimen 1.—Brandon Mountain, Kerry, Ireland, Carroti; Wicklow, D. 
Moore, in Herb. Carroll. On one specimen there is a number of large black 
cones, resembling the pycnides of Dichena rugosa, evidently parasitic, and having 
no relation to the Soloria, further than that they grow on it. They are closely 
ageregated or grouped on the surface of the thallus, to which they give a very 
irregular warted character. The stylospores are very large—about ;th to ath long 
and smth broad—apparently normally 1-septate, colourless, full of granular or 
grumous matter. 
FAMILY X. CETRARIA. 
GENUS I. Cerraria, Ach., Nyl. 
NYLANDER has retained three species in the old genus Cetraria, viz., the fruti- 
culose species,—placing those having a flat, broad, Parmelioid thallus in a separate 
genus,—Platysma. Undoubtedly, both groups are comparatively natural ; still it 
admits of doubt how far it is advisable to constitute two genera, rather than 
merely two sections of a single genus. The spermogones differ somewhat in the 
two groups or genera. In Cetraria they are more of the character of those of 
Cladonia than in Platysma. «They are barrel-shaped organs, seated on the apices 
of the ultimate ramuscles of the thallus, as in acu/eata, or on cilia, fringing the 
margins of the laciniz, as in /slandica. In neither case are they very con- 
spicuous, unless on careful examination. They are of the same colour as the 
thallus; hence the line of separation or junction of the thallus and_ sper- 
mogone is not so distinct as in Cladonia. Neither are they so large nor so 
distinctly barrel-shaped as in that genus. They vary greatly in length, being 
