Vlll 



DESCRIPTION OP THE PLATES. 



Fig. 24. Vertical section of a gymnocarpous apothecium. — 

 a. Exciple. b. Thalamium. 



25. Vertical section of an angiocarpous apothecium. — a. Ex- 

 ciple. b. Thalamium. 



26-30. Germinating spores. 



26. Lecanora pallescens, var. parella. 



27, 28. Parmelia par ietina. 



29. Splicer oplior on compression. 



30. Lecanora subfusca. 



31. Vertical section of apothecium of Physcia ciliaris. — a. Pa- 

 raphyses. b. Paraphyses acted on by iodine, c. Thecse contain- 

 ing the spores, tinged blue by iodine, d. Hypothecium. 



32. Gonidia. — a. Mature, b. In process of fissiparous division. 

 c. Emptied of their contents, d. Nuclei or contents, after their 

 escape. 



33. Hypothallus developed around the spore of Cladonia ex- 

 terna. 



34. Gonidic mother- cells from young plants of Parmelia pa- 

 rietina. 



PLATE II. 



1 . Vertical section of apothecium and thallus of Parmelia pa- 

 r ietina. — a. Tuberose extremities of paraphyses. b. Thecse con- 



Schserer. In our own researches on the general or special microscopic ana- 

 tomy of the Lichens, we have usually employed the magnifying power 380 of 

 Nachet's (Parisian) microscope. 



