Fig. 29. A, Trentepohlia umbrina Born.; B, T. aurea Mart. × 300 (after Kütz.).
Fig. 30. Example of Cladophora. Cl. glomerata Kütz. A, nat. size; B, × 85 (after West).
Fam. Trentepohliaceae. Filamentous and branched, the filaments short and creeping or long and forming tufts and felts or cushions; colour, brownish-yellow or reddish-orange.
Trentepohlia Born. Branching alternate; cells filled with red or orange oil; no pyrenoids ([Fig. 29]). A large number of lichens are associated with this genus: Pyrenulaceae, Arthoniaceae, Graphidaceae, Roccellaceae, Thelotremaceae, Gyalectaceae and Coenogoniaceae, etc., in whole or in part. Two species have been determined, T. umbrina Born., the gonidium of the Graphidaceae, and T. aurea which is associated with the only European Coenogonium, C. ebeneum ([Fig. 3]). Deckenbach[287] claimed that he had proved by cultures that T. umbrina was a growth stage of T. aurea.
Fam. Cladophoraceae. Filamentous, variously and copiously branched, the cells rather large and multinucleate.
Cladophora Kütz. Filaments branching, of one-cell rows, attached at the base; colour, bright or dark green; mostly aquatic and marine ([Fig. 30]). Only one lichen, Racodium rupestre, a member of the Coenogoniaceae, is associated with Cladophora. It is a British lichen, and is always sterile.
Fam. Mycoideaceae. Epiphytic algae consisting of thin discs which are composed of radiating filaments.