DISTRIBUTION 351 



lichens of Australia and Tasmania to which countries a few tropical species 

 of Graphis, Chiodecton and Trypethelium have migrated. Various unusual 

 types are to be found there also: the beautiful Cladonia retepora (Fig. 71), 

 which spreads over the ground in cushion-like growths, with the genera 

 Thysanotheciiiin and Neophyllis, genera of Cladoniaceae endemic in these 

 regions. 



I 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, Miiller' found that there was a great affinity 

 between these two countries. Of the Palestine species, eight were cosmo- 

 politan; 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^' 

 listed all of the species known, amounting to 1 593, and new plants and new 

 records have been added since that day. The familiar genera are well 

 represented, Nephromiuin, Xanthoria, Physcia, Parmelia, Ranialina and 

 Roccella, some of them by large and handsome species. In the Sahara 

 Steiner^ 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* 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' Lichens du Bresil 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. spiiriella and P Americana, the two latter being new species. Sticta 

 (including Stictina) includes only five species, and Coenogoniwii three. There 

 are 39 species oi Parmelia with 33 oi Lecanora and 68 of Lecidea, many of 

 them new species. 



1 Miiller-Argau 1884. ^ Stizenberger 1888-1895. ^ Steiner 1895. 



* Flagey 1893. * Wainio 1890. 



