BULLETIN OF THE UNITED STATES NATIONAL MUSEUM Contributions from the United States National Herbarium Volume 34, Part 7 (End of Volume) THE LICHEN GENERA CETRELIA AND PLATISMATIA (PARMELIACEAE) By William Louis Culberson and Chicita F. Culberson ■t SMITHSONIAN INSTITUTION PRESS • WASHINGTON, D C. * 1968 Contents Page Introduction 449 Historical Background 450 The "Parmelioid" Cetrariae 451 Morphology 456 Cortex 457 Pseudocyphellae 458 Puncta 458 Isidia 459 Soredia 460 Lobulac 460 Apothecia 461 Ascospores 462 Pycnidia 463 Chemistry 464 Biosynthetic Dichotomy Leading to Aromatic and Aliphatic Sub- stances 465 Orcinol- and jSf-Orcinol-type Substitutions 465 Length and Oxidation State of the Side Chain in Orcinol-type Phenolic Acids 467 Depsides and Depsidones 469 O-Methylation 471 Relationship of Cetrelia Compounds to Other Lichen Substances . 472 Methods for the Microchemical Identification of Lichen Substances in Cetrelia and Platismatia 473 Solutions 474 Microextraction 475 Microcrystal Tests 475 Paper Chroma tog rap hy 475 Hydrolysis of Depsides 477 Thin-layer Chromatography 477 The Identification of Specific Substances 478 Alectoronic Acid and «-Collatolic Acid 478 Anziaic Acid 479 Atranorin 480 Caperatic Acid 480 Fumarprotocc;traric Acid : 481 Imbricaric Acid 482 Microphyllinic Acid 483 Olivetoric Acid 484 Perlatolic Acid 484 An Unidentified Substance 485 Chemical Criteria in the Taxonomy of Cetrelia and Platismatia . ..... 486 Acknowledgments 490 hi IV CONTRIBUTIONS FROM THE NATIONAL HERBARIUM Pftgu Tiixonomic Treatment 490 Cetrelia Culb. & Culb 490 Artificial Key to the Species of Cetrelia 491 Cetrelia alaskana (Culb. & Culb.) Culb, & Culb 492 Cetrelia braunsiana (Miill. Arg.) Culb. & Culb 493 Cetrelia cetrarioides (Del. ex Duby) Culb. & Culb.. 498 Cetrelia chicitae (Culb.) Culb. & Culb. 504 Cetrelia collata (Nyl.) Culb. & Culb 505 Cetrelia davidiana Culb. & Culb 507 Cetrelia delavayana Culb. & Culb 509 Cetrelia isidiata (Asah.) Culb. & Culb 510 Cetrelia japonica (Zahlbr.) Culb. & Culb. 511 Cetrelia nuda (Hue) Culb. & Culb 513 Cetrelia olivetorum (Nyl.) Culb. <fc Culb 515 Cetrelia pseudolivetorum (Asah.) Culb. & Culb 519 Cetrelia sanguinea (Schaer.) Culb. & Culb 521 Cetrelia sinensis Culb. & Culb 523 Platismatia Culb. & Culb 524 Artificial Key to the Species of Platismatia 525 Platismatia erosa Culb. & Culb 526 Platismatia formosana (Zahlbr.) Culb. & Culb 529 Platismatia glauca (L.) Culb. & Culb 530 Platismatia herrei (Irnsh.) Culb. & Culb 537 Platismatia interrupta Culb. & Culb 539 Platismatia lacunosa (Ach.) Culb. & Culb. 541 Platismatia norvegica (Lynge) Culb. & Culb 543 Platismatia regenerans Culb. & Culb. 547 Platismatia stenophylla (Tuck.) Culb. & Culb 548 Platismatia tuckermanii (Oakes) Culb. & Culb 549 Literature Cited 554 Index 557 THE LICHEN GENERA CETRELIA AND PLATISMATIA (PARMELIACEAE) By William Louis Culberson and Chicita F. Culberson Introduction In 1960 we undertook a monographic study of the old genus Cetraria in the traditionally broad sense that it was understood in Zahlbruck- ner's Catalogue Lichenum Universalis. It soon became obvious that this assemblage contained several major constellations of species and that these species groups were not particularly closely related to each other. One of these major groups is of course Cetraria itself, and this genus will be the subject of a future publication. A small, homoge- neous, arctic-alpine segregate genus named Asahinea has already been treated (Culberson and Culberson, 1965). Two groups remain—the new segregate genera Platismatia and Cetrelia. The aim of the present study is to describe and delimit these genera and to present a compre- hensive treatment of the species which belong to them. This study has the additional objective of examining the nature of chemical variation in morphologically well defined species groups. It was obvious early in our research that the plants under study showed chemical variations strikingly correlated with morphologic ones. Moreover, the chemical compounds themselves seemed to have closer relationships to each other than those previously noted in other genera of approximately the same size. We decided, therefore, to treat chemistry and morphology in equal detail in our study. Of course, the use of chemistry in lichen taxonomy is now so common- place that it is impossible to imagine a serious treatment of any group showing chemical diversity in which this aspect of the variation was left unstudied. Few lichenologists, however, have tried to in- tegrate chemical and morphological data or to place chemical varia- tion in the same evolutionary frame of reference in which critical taxonomy places morphological variation. But if we are to involve chemistry in taxonomy, an attempt, however crude, must be made to delineate the nature of chemical variation in lichens. In this mono- graph we present two genera to serve as subjects for the kind of 449 450 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM theoretical speculation that will lead eventually to the structuring of a framework of principles upon which practical taxonomic judgments can rest. Historical Background From the very beginning, generic concepts have been one of the most unsatisfactory aspects of the taxonomy of lichenized fungi. Linnaeus, in his Species Plantarum of 1753, considered all the species as members of the single genus Lichen and, to the detriment of lichen- ology, the insensitive Linnaean treatment was selected as the starting point for the nomenclature of the whole group. Even Acharius, the first botanist to see the lichens with a discerning and critical eye, began by keeping all the species in the genus Lichen (Acharius, 1798), ob- viously simply in deference to tradition. A few years later though, in 1803, he divided the lichens into some two dozen genera, one of them being Cetraria. As originally described, the genus Cetraria contained eight species, namely: C. islandica (L.) Ach. C. fallaz (L.) Ach. C. cucullata (Bell.) Ach. C. glauca (L.) Ach. C. nivalis (L.) Ach. C. sepincola (Ehrh.) Ach. C. lacunosa Ach. C, juniperina (L.) Ach. The genus soon became a general repository for all parmeliaceous plants with marginal or submarginal apothecia. It was used in its Acharian sense for the species listed above and for related species by most of the major lichenological authors of the nineteenth century, for example, Schaerer, Fries, Tuckerman, Korber, and Massalongo. Nylander alone among the leading lichen students of the time arranged the species differently. He took up the almost forgotten genus Pla- tisma described by Hoffmann in 1790—although he changed the spelling to "Platysma"—and used it to classify all but one of Acharius' Cetra- riae (Nylander, 1855). In so doing, he effectively typified the genus Cetraria Ach. with Lichen islandicus L. by leaving only that species in it (Culberson, 1966b). Nylander's revival of Platysma reflected his belief that Cetraria, as conceived by other botanists of the time, was not homogeneous. Although all these species had marginal or submarginal apothecia and pycnidia, it was difficult to find any other major traits shared by even the restricted list of species that Acharius originally put into the genus. In the original complement of species listed above, Nylander saw the erect, linear-lobed, subfruticose, soil-inhabiting (1etraria vilandica as an element too foreign from the other more distinctly foliose species to be classified in the same genus with them. Nylander, however, apparently did not question the generic affinity of all the foliose species that he recognized in Platysma. He saw no obstacle to CULBERSON & CULBERSON—CETRELIA AND PLATISMATIA 451 classifying the broad-lobed, Parmelia-like Cetraria glauca and the narrow-lobed, erect, soil-inhabiting species such as the familiar C. cueullata and C. nivalis in the same genus. As time passed, other workers described many more species in Cetraria, and the generic concept became more nebulous still. There were species with marginal, reflexed apothecia, such as Cetraria stracheyi Bab., that in some later classifications were transferred to the genus Nephromopsis Mull. Arg. There was also a whole array of very broad-lobed forms, most of them foreign to Europe and superficially resembling the Amphigymnia Parmelias, for example Cetraria sangui- nea, C. coUata, and C. japonica from the Orient. In addition, a few particularly anomalous species, such as C. ckrysantha Tuck, and C. tkomsonii Stirt., were put in Cetraria in spite of their lacking any con- nection whatever with the bulk of the species already classified there, except for having marginal apothecia. The Catalogus Lickenum Universalis (Zahlbruckner, 1930) took a particularly broad view of Cetraria and included all the plants men- tioned above and most of their obvious relatives, excluding only a few of the species as members of the genus Nephromopsis. Zahlbruckner's Catalogus had the effect of rigidly formalizing these generic concepts. With the exception of this study, subsequent treatments have either followed him in recognizing Cetraria and Nephromopsis (Rasanen, 1952) or have taken a still more conservative position and recognized only Cetraria (Rassadina, 1950). Only Eilif Dahl tried to evaluate the major variations among the plants that had been referred to Cetraria and to define the major natural groups in an assemblage of species that years of casual taxonomy had left biologically meaningless. The "Parmelioid" Cetrariae Dahl challenged the monophyletic nature of Cetraria sens. lat. He pointed out that