34 



we find sometimes many disks confluent in one (apolh. symphycar- 

 pcea). There are many forms of composite-conglomerate apothe- 

 cia. The apothecia of Umbilicaria are typically simple, and either 

 scutelliform like those of Lecidea, or lirellseform like those of Ope- 

 grapha, but their gyrose-plicate evolution is so normal (even when 

 the plica? are deficient, the disk being chinked) that we are com- 

 pelled to regard them, taking their other characters into considera- 

 tion, a distinct genus. 



Obs. Eschweiler's latest views of the apothecia (Fl. Brasil. 1. c.) 

 may be referred to, as also those expressed in his Systerna. No 

 one has studied the structure of these parts more accurately. 



Auct. de Metamorphosi : Fries, Lichenogr. p. 63; Meytr, Ent- 

 wick. p. 314, &c. ; Eschweiler, Syst. 1. c. and FI. Bras. I.e.; Wallroth, 

 Naturg. der Fiecht. 1. c. 



IV. ANAMORPHOSIS. 



To abnormal development Lichenes are peculiarly exposed. The 

 far greater frequency of the propagation by gonidia, producing new 

 individuals of the original thai 1 us only, gives rise to a vast number 

 of varying, more or less imperfect, and atypical states. The mo- 

 nographical study of the class, without regard to the typical or aty- 

 pical state of the forms of vegetation referred to it, or to the endless 

 analogies of development in different genera, long obscured the 

 scientific system of these plants, and infected it throughout with 

 error. But besides the gonidial propagation, the variation of 

 lichens has other and no less active causes, in climate, station, 

 age, and mechanical obstruction; and yet again in the original indi- 

 viduality of every species, developing progressively or regressively 

 from its ideal type. It is, then, a wide field, that of the. anamor- 

 phosis of lichens ; one, indeed, which embraces the whole circuit 

 of lichenose vegetation. In its history, the names of Fries, Wall- 

 roth, and Meyer will be always preserved. 



The anamorphoses of the hypothallus are especially fallacious, 

 since herein the whole lichenose habit disappears, and that of a 

 Byssus is counterfeited (the hypothallus, considered per se, being 

 itself a byssaceous development). In places exposed to the sun, 

 this byssoid degeneration is more simple, as in the case of Bys- 

 sus antiquitatis, L., which is derived from a black hypothallus. 

 But in moist places it appears as floccose, often somewhat ccespi- 

 tose, masses, of various stature, which occur in large patches, and 

 in the mountains of Sweden have been satisfactorily referred to 

 various Lecidese, Biatorce, and ParmelisB ( Patellaria). These 

 byssoid states of lichens have been described as ConferveaB by 

 authors, and with lichenists they have passed sometimes for acci- 

 dental excrescences of lichenose vegetation, their apothecia, when 

 they occurred, being taken to be fungi. 



We have next briefly to glance at the anamorphoses of the thal- 

 lus. These are referable in part to the gonidial propagation gen- 

 erally, that is, to the germination of the cells of the gonimous layer, 

 either normally or abnormally, producing, in the first place, new 



