226 DR LAUDER LINDSAY ON THE SPERMOGONES AND PYCNIDES 








sionally perforated by an irregular hole or fissure. This erosion or perforation is 
analogous to what occurs in Umbilicaria erosa, and other lichens. Either apothecia 
or thallus may be erose or perforated ; but such erosion is accidental—not pecu- 
liar to any one species or variety—and does not therefore furnish a good dis- 
tinctive character. The thecze and spores of P. pertusa are generally larger than 
those of P. physodes ; but there are few species in which the thece and spores are 
uniformly of the same size. They usually vary more or less in different specimens 
of the same species from different localities. The spermogones of P. pertusa are 
identical with those of P. physodes, but they are less common and less plentiful. 
SPECIES 14. P. cincinnata, Ach. 
Specimen 1.—Staten Land, Cape Horn; in Herb. Hooker, Kew; also collected 
by A. Menzirs, 1787, in Herb. Menzies, Royal Botanic Garden, Edinburgh. If this 
plant is not a form of P. physodes, which I am inclined to regard it, it is at least 
very closely allied. The lacinize are bullose at their extremities in both sets of 
specimens; in MENzIEs’s, occasionally pertuse. In both cases the spermogones are 
abundantly scattered over the ends of the lacinize, as black or brown, punctiform, 
immersed bodies. The spermatia are acicular, about auth long, and sath broad. 
The sterigmata consist of a few delicate cylindrical articulations or cells, as in 
P. physodes. 
Species 15. P. placorodia, Ach. 
Specimen 1.—On the trunks of trees, Troy, U. S., America; in Herb. Hooker, 
Kew. The plant greatly resembles P. tzliacea. The spermogones are scattered 
generally in round, closely aggregated groups, about the ends of the lacinize, as 
black, immersed, punctiform bodies. The spermatia are acicular, about sth long, 
and ssinth broad, on sterigmata about jth long, which consist of several articu- 
lations, as in P. tiliacea. 
Species 16. P. sazxatilis, Ach., 
Which occurs in Europe, Africa, America, and Asia. There is one very well-marked 
variety, omphalodes, Ach., Fr., which occurs in Europe and Asia—the Parmelia 
omphalodes of the earlier lichenologists. It has no claim, however, to rank as a 
separate species ; the gradations between it and the type are easily studied. Its 
apothecia and spermogones alike are those of P. saxatilis. The spermogones are 
generally very minute, black, punctiform, wholly immersed bodies, scattered 
over the ends of the laciniz, always on smooth ones, seldom or never on fur- 
furaceous ones ; or, if they occur on the latter, they are so minute and inconspi- 
cuous that they are overlooked. ‘The ostiole is flat or depressed, seldom papille-— 
form. Normally it is round, and exceedingly minute; but with age it becomes 
triangular or stellate-fissured, with turgid, prominent borders or not. The ends” 
of the lacinize, especially in var. omphalodes, are frequently studded over with 
