THELOTREMA. 223 



XXXVII. THELOTREMA (Ach.) Eschw. 



Apotheeia urceolate, very various, but illustrating by 

 their modifications tbe scutellseforrn type; consisting of a 

 variously coloured proper exciple, with somewhat torn mar- 

 gin, which is concrete with a (now obsolete) thalline one, 

 and includes a disciforin or nucleiform nymenium, itself 

 clothed more or less with an interior exciple, or veil. Spores 

 from ellipsoid often oblong ; bi-plurilocular ; or murifonn- 

 multilocular; brown or decolorate. Spermatia scarcely 

 known. Thallus crustaceous, uniform. A certain luxu- 

 riance of difference is observable in the characters of this 

 as of other intertropical groups, which, while little was 

 known of them, were taken to indicate more than a few 

 genera and species. But, with advance of knowledge, it 

 has become clear that the strongest structural contrasts of 

 Thelotrema, as here taken, find their sufficient reconcilia- 

 tion within the group ; and that it is from this larger point 

 of view that (as elsewhere so here) we best observe and 

 follow Nature. As respects our own handfull of species it 

 should yet be said that much is doubtless to be added to it 

 from the extreme southern States ; and that, at any rate, all 

 attempt at an arrangement in sections must, for the present, 

 be only provisional. Some illustration of the above remarks 

 may be found in the writers Genera Lichenum, pp. 135-139. 



* Spores bi-pluri-locular with entire spore-cells, colourless for 

 the most part but not always ; and finally brotvn in 5. 



1. T. microporum, Mont. ; thallus cartilagineous, chinky ; 

 glaucescent ; apothecia minute, immersed, urceolate, open; a 

 white interior exciple concrete for the most part with, and not 

 exceeding the thallus, bordering a pale - flesh - coloured disk; 

 thalline exciple obsolete. Spores ellipsoid ; 4-locular ; ^ mic. 



Mont, in Ann. Sci. 3, 12, 130; Syll. 36. 

 Bark of Magnolia grandijlora, Gainesville, Florida, Mavenel. 



Differs from the T. microporum published by me in Lick. 

 Cub. n. 124, which is exactly Montagne's plant (Herb. Jung- 

 huhn) much as the T. album of Lick. Cub. n. 127 : but the spe- 

 cific distinctness of the two Cuba lichens is not clear ; any more 



