BY JOHN SHIRLEY, D.S.C. 67 



importance is assigned to the microscopic structiu"ei of tli© 

 fruit than was allowed by Nylander and Crombie in their 

 scheme of classification. The systematic value of the form, 

 colo'ur and septation of the spores had, however, been 

 recognised by Massolongo and other continental Lichen- 

 ologists, and by Mudd in our' own country." 



The system adopted is, in fact, that devised by my 

 correspondent of many years, the late Dr. Jean Muller of 

 G-eneva, and perfect^^d by Dr. Zahlbriickner in Engler and 

 Prantl's Pflainzen-familien. To show the want of con- 

 cordance under this system, let us look at the place assign- 

 ed to Parmelia by a few of the great modern lichen- 

 ologists : — 



(1) A. M. Hue, Nouvelles Archives du Museium 

 d'hist. Nat. 3e series. T. IT., unites Evernia, 

 Eveirniopsis, and Anzia with Parmelia under 



Parmeliei, but separates from these Sticta and 

 Stictina. 



(2) Jatta, in "Lichenum Italite Meridionalis," 

 places tuider Parmelias — Cetraria, Peltigera, 

 Nephroma, Solorina, Sticta, Imbricaria, Parmelia, 

 and Physcia. 



(3) Dr. Jean Muller, "Lichenes Ernstiani," Hed- 

 wigia. Band XXXIV., 1895, etc., etc., unites un- 

 der Parmelias — Sticta., Stictina, Parmelia, Anzia, 

 Pseudo-physcia (or Anaptychia), and Physcia. 



(4) Fink, in the "Lichens of Minnesota," pp. 190- 

 210, groups under Parnieliaceje — Parmelia., Cetra- 

 ria, Evernia, Ramalina, Alectoria, and Usnea. 



It is evident that dependence on the microscopic 

 structure of the apotheeium may separate species but will 

 not give the major feature of classification. 



To divide the genera into orders a microscopic ex- 

 amination of the thallus is also necessary. In Sticta, 

 Stictina, and Parmeliai both an upper and a lower cortex 

 are present; and the thalli are provided with cyiDhellse or 

 absorption jDores. In Sticta and Stictina there are, be- 

 sides the cyphellae, openings in the upper cortex. These 

 are not joined to the cyphell^ by tubes, but by air passages 

 of irregular shape ramifying through the thallus, and 

 best studied in >S'. suhorhicularis. 



Physcia and Solorina have an upper cellular cortex, 

 but in Physcia liypoJeuca and Solorina hisjyora there is a 

 lower pseudo-cortex of hyphee passing into rhizinas. The 



