(194) 
nigro. Spore e dactyloideo fusiformi-oblonge, quadri-pluriloculares, 
incolores. Spermatia oblonga 1. bacillaria; sterigmatibus simplici- 
bus. Thallus crustaceus uniformis. 
All but one (Z. Leprieurii (Mont.) of tropical America) of the seven 
or eight species are northern. Another (L. premnea (Ach.) Tuck. l. c.) 
extends however, perhaps throughout the warmer regions of the earth; 
and offers, in these regions, some often notable varieties. The relation 
of the lecideoid species to the present tribe is mediated by the closely 
akin LZ. illecebrosa (a Lecidea, according to Acharius, Scherer, and 
Nylander) and Z. lyncea, which Borrer, Scherer, and Nylander have 
referred to Opegrapha. 
With the exception of L. Lepricurii, all the species are European; 
but only two have as yet been observed here. . abietina (Ach.) 
Koerb., is, according to Hooker (in Richards. Append. to Frankl. Narr.) a 
native of arctie America (Richardson) but has not been found elsewhere 
in North America, except on Abies grandis, in California (Mr. Bolander) 
where it is accompanied by its remarkable spermogones, the spermatia of 
which measure as micromill.—L. premnea (Ach.) Tuck. Obs. Lich., a 
widely diffused, tropical lichen, reaching also into the northern hemis- 
phere,—where it had yet so passed out of knowledge, before the 
publication of the Prodromus of Nylander, that Montagne could describe 
the Java plant as a new species (Lecid. coniochlora) —has occurred, on 
Cypress, in Louisiana (Hale) the specimens agreeing, externally, with 
tropical ones (Hong Kong, Mr. Wright) and the spores, (measuring 
0,019-0,023"™™- in length, and 0,003-0,005™™- in width) sufficiently with 
those of Nyl. Lich. Par. nu. 67. From this cannot be separated a 
generally similar lichen, from Pine, and Oak bark in California (Mr. 
Bolander) the spores of which measure 0,015-0,021™- in length, and 
0,003-0,005™™"- in width. Nor, in that case, is our New England plant 
(Z. chloroconia, Tuck. 1. c.) found, on various trunks, in Massachusetts, 
and New Hampshire (Myself) as in Vermont (Mr. Frost) and western 
New York (Mr. Willey) and the spores of which scarcely exceed 0,011- 
0,017™™ in length, by 0,003-0,005™™ in width, any longer to be kept 
apart, except (presenting, as it does, much the smallest spores known in 
the rather large group of forms which I hare ventured, at the above- 
cited place, to bring together under ZL. premnea) we admit it to the rank 
of a variety,—v. chloroconia. 
XLVII.—PLATYGRAPHA, Nyl. 
Nyl. Classif. 2, p. 188; Prodr. p. 161; Lich. exot.1.¢.; in Prodr. Fl. N. 
Gran. p.93. Anz. Catal. Sondr. p.93. Mudd Man. Brit. Lich. p. 244. 
Lecanore sp., Ach. Lecidex sp., Fr. L. E. p. 337. Schismatomma, 
Flot. & Koerb. in Koerb. Grundr. d. Cryptogamenk. Koerb. Syst. 
