The Parmelia quercina group in North-America

CIJLBERSON, WILLIAM L. (Duke U., Durham, N. C.). The Parmelia quercina group in NorthAmerica. Amer. Jour. Bot. 48(2): 168-174. Illus. 1961.-A study of the morphology and lichen chemistry of the North American members of the Parmelia quercina complex leads to the recognition of 5 species: P. quercina (Willd.) Vain. (California), P. coronata Fee (Mexico), P. confoederata Culberson sp. nov. (southeastern United States), P. galbina Ach. (eastern North America) and P. livida Tayl. (eastern and south central United States). All species produce the depside atranorin. P. quercina and P. confoederata also produce the depside lecanoric acid, and the closely related P. coronata produces gyrophoric acid, chemically similar to lecanoric acid. P. galbina contains a previously reported but chemically unknown depside, the aliphatic triterpene zeorin, and an unidentified yellow pigment and is thus chemically very distinct from P. livida which produces an unknown substance reported here for the first time. Species descriptions, synonvmy and distribution maps are provided. IN NORTH AMERICA the most conspicuous foliose, bark-inhabiting lichens belong to the large and variable genus Parmelia. Most bark-inhabiting Parmeliae without isidia or soredia belong to the P. quercina group or to the pseudocyphellate P. bolliana group. The second group has already been studied (Culberson and Culberson, 1956). During that investigation, it became apparent that the species c.oncept then in use in the related P. quercina group ill-reflected the real nature of the morphological and the chemical variation there. The aim of the present study, then, is to delimit the North American species of the Parmelia quercina species complex. MATERIALS AND METHODS.-About 1,200 pertinent specimens from the 20 American herbaria with the largest lichen collections were studied. The herbaria are referred to in this paper by the usual abbreviations. In the preparation of maps, an attempt was made to show every station by a dot, but from heavily collected areas many more specimnens were seen than, for obvious reasons, can be plotted. Only geographically or nomenclaturally critical specimens are cited in the text. The reagents for the thallus spot tests were: (1) a saturated aqueous solution of KOH; (2) a saturated aqueous solution of Ca(OCl)2; and (3) an approximately 2% solution of p-phenylenediamine in absolute ethanol. The procedure for microchemical extractions of lichen substances from thallus fragments has already been described (Culberson and Culberson, 1956). The following reagents were used in this study on micro-extracts to produce identifiable crystals: (1) 1 part o-toluidine, 2 parts glycerine, 2 parts ethanol (GAo-T solution for atranorin and the unknown substance in P. galbina); (2) 1 part aniline, 2 parts glycerine, 2 parts ethanol (GAAn solution for the unknown substance 1 Received for publication June 29, 1960. This study was subsidized by the L)uke University Council on Research. in P. galbina); (3) 1 part quinoline, 2 parts glycerin, 2 parts ethanol (GAQ solution for lecanoric and gyrophoric acids); (4) equal parts of glycerine, ethanol and water (GAW solution for the unknown substance in P. livida); (5) 3 parts glacial acetic acid, 1 part glycerine (GE solution for zeorin). The formulae for these and other crystallizing agents have been given by Asahina and Shibata (1954). TREATMENT OF THE SPECIES. 1. Parmelia quercina (Willd.) Vain. Termeszetrajzi Fiizetek 22: 279. 1899. (ubi synonymia integra). Lichen qutercinus Willd., Florae Berolinensis prodromus, 1787, p. 353 (secund. Vain.). Thallus middle size to large, to 12 cm. broad; lobes 2-4 mm. (exceptionally to 7 mm.) broad, appressed to slightly ascendent, smooth or only slightly wrinkled. Upper surface clear ashy white or only faintly tinged with brown; lower surface jet black and rhizinate to the edge or with a narrow, naked, pale-brown marginal zone. Upper cortex 13-26/i thick; medulla 117-220t thick, white; lower cortex 13-21,thick. Apothecia numerous (plants rarely sterile), saucer-shaped or flat, round to irregular, 1-5 mm. broad (exceptionally to 10 mm.), the undersurface of the thalline exciple rhizinate in most American specimens. Spores subglobose to ovoid, 4-7 X 7-13,U. Reactions: upper cortex KOH + yellow, Ca (OCl)2-, p-phenylenediamine-; medulla KOH-, Ca(OCl)2 + red, p-phenylenediamine-. Substances: atranorin and lecanoric acid (see photographs of the crystals of these substances in Culberson and Culberson, 1956). On trees, rarely on rock. Widely distributed in California (fig. 9); Japan to western Europe. North American specimens of P. quercina are in general more robust than European ones and have abundant rhizines on the under surface of the thalline exciple of most apothecia. In Europe, some lichenologists classify such specimens as P. carpor-