THALLOPHTTA. 



695 



tevr genera of Pyrenolichenes, including Verfucaria, Ephehe, Endocarfjon, and 

 Spfum-ophorus. 



BasidioUehen^s. — These occur only in tropical countries, and a number of genera 

 were formerly distinguished, including Cora, Dictyonema, and Lav.da.tea. Cora 

 pavonia, the best-known form, consists of a greenish-rellow, fan-like, concentricallv- 

 striated thallus which produces its basidia on the under surface and contains Ch roo- 

 coecus-celis as its Alga; Dictyonema-, on the other hand, consists of thin plates of 

 rather felty consistency, in which the radiating character of the strands is very 

 apparent; these dehcate plates, blue-green in colour, stand out from the tree-branch 

 to which they are attached. Laudatea, though resembling Ziidyonema, is a crus- 

 taceous form. Both the latter forms have 5cyfo/ie?7'/a-filaments as Alg£e. Quite 



Fig. 394^ — Leean/yra eiCuXenta. 



recently it has been shown by A. Moller, a naturalist who resided several years in 

 Brazil, that aU these supposed distinct Lichens are different growth-forms of one 

 Mid the same lichen. In addition to finding each of these forms in connection 

 with the other — ^so that there is no doubt of their continuity — he fotmd attached to 

 the CVwa-f orm the Ftmgus growing free from all trace of the Alga : this Ftmgus is 

 one of the Telephorese {cf. p. 68Sj, and when it is supplied with Cliroococcui-c(t\\s 

 grows into the Cora-form. This seems to be the only well-ascertained instance in 

 which a lichen-fungus has been found growing wild independent of an AJga. The 

 Ihctyon^rria- and Laudatea-fomis consist of the same Fungus growing upon Seyto- 

 nema instead of Ghroococcus. In the Laudatea-iorm the Alga seems to get the 

 upper hand and to determine the growth of the thallus. Cora and its various 

 growth-forms is certainly the most interesting, as it is also the most beautiful of aU 

 lichens of which we have any knowledge. 



Gasteroliehenes. — ^A Lichen from the Gasteromycetes has also been recognized; it 

 is a little, shortly-stalked, puff-baU-like form resembling a Lycoperdon {cf. p. 690). 

 The AJga (a PaZmelia) is restricted to the peripheral portions of the Lichen, which 

 is named EmericeUa variecolar. 



