(21) 
p. 23. Parmelia et Menegazzia, Mass. Neag. p. 3. Parmelia, Platys- 
matis spp., et Squamarize spp., Nyl. Prodr.; Syn. 1, pp. 375, 309. 
Imbricaria et Menegazzia, Koerb. Parerg. p. 28. Imbricaria (I. tristi 
excl.) Anz. Catal. p.25. Parmelia (Everniopsi excl.) et Anzia, Stizenb. 
Beitr. l. c. p. 174. 
Structuram descripserunt Tulasne, Mém. p. 139, t. 2, f. 18-23; 
Speerschneider, in Bot. Zeit. 1854, pp. 481, 499, t. 12; Schwendener, 
Untersuch. 1. ¢. 3, p. 157, t. 8. f. 3-6. 
Apothecia scutelleeformia, subpodicellata. Spore ex ovoideo 
ellipsoidese oblongaeve, simplices, incolores. Spermatia oblonga me- 
dio constricta apicibus plerumque acutis, raro acicularia; sterigmat- 
ibus pauci-articulatis 1. subsimplicibus. Thallus foliaceus, lobato- 
laciniatus, appressus, raro adscendens evernieformis, rarissime con- 
strictus filiformis, submembranaceus. 
Of the (fifty, more or less) conspicuous forms belonging to this genus, 
nearly two-thirds occur within our territory. The central, typical char- 
acter of the group is indicated by the marked predominance of horizon- 
tal forms; but its near relation to the preceding family is also evident, not 
only in the depressed Cetrarig, but in its own tendency, observable in 
every well-developed subdivision, to pass into ascendant, evernioid states. 
Considered in its full extent, the subdivision represented by P. levigata 
may be taken as exhibiting most fully the generical type. This species 
touches, on the one hand, an American lichen (P. cetrata, Ach., itself a 
state of P. perforata) and through this is immediately connected with P. 
perlata, which, though looking rather away from the present genus 
towards Cetraria, is yet of all others most remarkable for size ; while, on 
the other, and in its own line of differentiation (analogous to the specific 
evolution of Physcia speciosa as here taken) we have an elegantly diver- 
sified series of Parmeliine forms, passing at length into Physcioid (P. 
physcioides, Nyl., the same it should seem with P. pinnatifida, Herb. 
Berol.) and finally, in P. Camtschadalis and its variety Americana, Nyl., 
now simulating Evernia furfuracea, and now even Physcia speciosa, v. 
leucomela. And it adds still further to the interest of this subdivision, 
that, though normally glaucescent, it often oversteps its series, and ap- 
pears in ochroleucous forms. Such are P. (perluta) latissima, v. flavida, 
Nyl. (Lindig Herb. N. Gran. n. 740) as also a similarly marked condition 
(P. perlata v. flavicans, Lich. Calif.) from California (Bolander) the last 
comparable rather with common states of P. perlata except in the 
larger spores; and one also (occurring from Harper’s Ferry in Vir- 
ginia to Louisiana) with the other peculiar features of P. crinita, Ach. 
Nor is this tendency to an intenser coloration confined to the cetrarioid 
wing of the group of species before us; being also marked in P. levigata 
y. sinuosa, Nyl., and in other varying, tropical forms, as P. reducens, Nyl. 
