. The natural history of plants, their forms, growth, reproduction, and distribution;. Botany. THALLOPHYTA. 695 few genera of Pyrenolichenes, including Verrucaria, Ephebe, Endocarpon, and SphcBTophorus. Basidiolichenes.—These occur only in tropical countries, and a number of genera were formerly distinguished, including Cora, Bictyonema, and Laudatea. Cora pavonia, the best-known form, consists of a greenish-yellow, fan-like, concentrically- striated thallus which produces its basidia on the under surface and contains Ghroo- cocctts-ceUs as its Alga; Bictyonema, on the other hand, consists of
. The natural history of plants, their forms, growth, reproduction, and distribution;. Botany. THALLOPHYTA. 695 few genera of Pyrenolichenes, including Verrucaria, Ephebe, Endocarpon, and SphcBTophorus. Basidiolichenes.—These occur only in tropical countries, and a number of genera were formerly distinguished, including Cora, Bictyonema, and Laudatea. Cora pavonia, the best-known form, consists of a greenish-yellow, fan-like, concentrically- striated thallus which produces its basidia on the under surface and contains Ghroo- cocctts-ceUs as its Alga; Bictyonema, on the other hand, consists of thin plates of rather felty consistency, in which the radiating character of the strands is very apparent; these delicate plates, blue-green in colour, stand out from the tree-branch to which they are attached. Laudatea, though resembling Bictyonema, is a crus- taceous form. Both the latter forms have /Sc^/towema-filaments as Algse. Quite. Fig. 394,—Lecmwra esculenta. recently it has been shown by A. MoUer, a naturalist who resided several years in Brazil, that all these supposed distinct Lichens are different growth-forms of one and 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 found attached to the Cora-form the Fungus growing free from all trace of the Alga; this Fungus is one of the Telephorese (cf. p. 688), and when it is supplied with Chroococcus-cells 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 Alga. The BictyoncTna- and Laudatea-iorma consist of the same Fungus growing upon Scyto- nemxi instead of Ghroococcus. In the Laudatea-iorm the Alga seems to get the upper hand and to determine the growth of the thallus. Gora and its various growth-forms is certainly the most interesting, as it is also the most beautiful of all Lichens of which we have any knowledge. Gasteroliche
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbotany, bookyear1895
