TORREYA 



October, 1915. 

 Vol. 15 No. 10 



THE GENUS CETRARIA AS REPRESENTED IN THE 

 UNITED STATES AND CANADA 



By R. Heber Howe, Jr. 



The species of this genus since 1753 have appeared under the i^fSV/ \ 

 following: Lichen L. 1753, Lichenoides Hoffm. 1790, Lobaria *^^JTa!\i 

 Hoffm. 1795, Platisma Hoffm. 1801, Physcia Michx. 1803, ^^Koi 

 Parmelia Spreng. 1825, Evernia Nyl. 1857, Platysma Nyl. 1858, 

 Cornicidaria Trevis & Mudd 1861. Few of these names are, 

 however, generic synonyms. 



The genus Cetraria was proposed by Acharius in 1803, and 

 has been variously limited by later authors. Though Acharius 

 included under his Cetraria various species now removed to 

 other genera, his species cannot be considered "altogether 

 incoherent," and the genus must be credited to him, particularly 

 as his type species has only been removed once (Mudd) from his 

 genus. 



Genus: CETRARIA* Ach., Meth. Lich. 293. 1803 

 (Subgenus: Stigmatophora Wain., Arkiv for Bot. 8: 20. 1909 



in part.) 

 (Section: Eucetraria Korb., Parerga Lich. 17. 1865.) 

 (B. Physcia Fr., System. Orb. Veg. 239. 1825.) 

 {Platyphyllum Vent., Tableau reg. vegetal, 2: 34, 1799.) 

 {Chionocroum Ehrh., Beitr. naturk. 4: 148. 1789.) 



Description: Thallus fruticose or subfoliose, laciniate, bi- 

 facial, brown or yellow; hyphal structure radial; cortex complex 

 (decomposed), medulla arachnoid, axis stupeous; gonidia proto- 

 coccoid, monostratified, heteromerous. 



* Cetra or Caetra = a short Spanish shield. 

 [No. 9, Vol. IS of ToRREYA, Comprising pp. 187-212, was issued 28 September, 1915.] 



213 



