The continent of Africa on the north and east is in so close connection with Europe and Asia that little peculiarity in the flora could be expected. In comparing small representative collections of lichens, 37 species from Egypt and 20 from Palestine, Müller[1089] found that there was a great affinity between these two countries. Of the Palestine species, eight were cosmopolitan; among the crustaceous genera, _Lecanorae_ were the most numerous. There was no record of new genera. The vast African continent—more especially the central region—has been but little explored in a lichenological sense; but in 1895 Stizenberger[1090] listed all of the species known, amounting to 1593, and new plants and new records have been added since that day. The familiar genera are well represented, _Nephromium_, _Xanthoria_, _Physcia_, _Parmelia_, _Ramalina_ and _Roccella_, some of them by large and handsome species. In the Sahara Steiner[1091] found that genera with blue-green algae such as the Gloeolichens were particularly abundant; _Heppia_ and _Endocarpon_ were also frequent. Algeria has a Mediterranean Flora rather than tropical or subtropical. Flagey[1092] records no species of _Graphis_ for the province of Constantine, and only 22 species of other Graphideae. Most of the 519 lichens listed by him there are crustaceous species. South America stretches from the Tropics in the north to Antarctica in the south. Tropical conditions prevail over the central countries and tropical tree-lichens, Graphidaceae, Thelotremaceae, etc. are frequent; further West, on the Pacific slopes, _Usneae_ and _Ramalinae_ hang in great festoons from the branches, while the foliose _Parmeliae_ and _Stictae_ grow to a large size on the trunks of the trees. Wainio’s[1093] _Lichens du Brésil_ is one of the classic systematic books and embodies the writer’s views on lichen classification. There are no new families recorded though a number of genera and many species are new, and, so far as is yet known, these are endemic. Many of our common forms are absent; thus _Peltigera_ is represented by three species only, _P. leptoderma_, _P. spuriella_ and _P. Americana_, the two latter being new species. _Sticta_ (including _Stictina_) includes only five species, and _Coenogonium_ three. There are 39 species of _Parmelia_ with 33 of _Lecanora_ and 68 of _Lecidea_, many of them new species. D. LICHENS OF TROPICAL REGIONS