MESSUTI Maria ines
capítulos de libros
Lichen Flora of the Greater Sonoran Desert Region. Vol. 2 (most of microlichens, balance of the macrolichens, and the lichenicolous fungi)
Lichens Unlimited
Lugar: Tempe; Año: 2004; p. 381 - 388
This volume is dedicated to Dr. B.D. Ryan, without whom this project could not have been undertaken, as he was one of the most knowledgeable lichenologists in the westem North Americanlichen flora. Because no comprehensive, modem lichen flora is avail­able for any region of North America outside of the Arctic and very recently Wisconsin and because the taxonomic literature is so diverse and scattered, a comprehensive li­chen flora for the Sonoran region is in progress, and this is the second of three volumes. In general, most lichens are independent, symbiotic organisms fomled by a mycobiont and one 01' more photobionts (green algae anci/or cyano­bacteria). In reality not all groups are fully lichenized (e.g., the Caliciales) and biological relationships can be quite complex, even within a genus. In some cases, it is becoming apparent that lichenizationmay have been lost. Furthermore, there are even a few examples of parasitic (lichenicolous) lichens growing on other 1ichens. In this flora grcmps are treated in full, including both lichenized and non-lichenized taxa and lichenicolous ones. In addi­tion, a few purely fungal genera have been included as well because they are frequent1y investigated by lichenologists· and are likely to be collected as 1ichens. In volume II, we a1so treat the lichenicolous fungi through the able editorial assistance of Dr. P. Diederich, who has also contributed many of the treatments. The target region (NW Mexico and SW USA) covers almost 600,000 km2 including the whole Sonoran Desert and adjacent regions up to the mountain crests of Arizona, southem California and the Siena Madre Occidental. Al­though we have collected in the region since the early 1970's, the impetus for developing the flora came from a major field expedition to Arizona and Baja California in Dec., 1988, to Jan., 1989. Well over 30 peop1e pmiicipated in thisexcursion and ma~y ofthem have become core contributors to the flora. Although the rare individual may gain sufficient expertise in a lifetime to write a flora, the philos- ophy behind this flora is that an assemblage of individual monographers wil! provide more thorough analyses. Because there are relatively few lichen monographers (les s than 10 active people in all of North America) and because lichens are relatively cosmopolitan (many species occur on multiple continents), it made sense to build an international team - now totaling over 70 scientists from 20 countries. Over 80% of those people have contributed to this volume alone. Because a specialist wil! find many more species of her/his group than a generalist is likely to find, a concelied effort was made to take the specialists .into the field. To revise a group, it is also essential that the specialist under­stand the inherent variability of herlhis group in the fie1d. Accordingly, 14 major expeditions throughout the whole Sonoran region were conducted, and almost every con­tributor participated on at least one expedition. The first volume covered almost 600 lichens, includ­ing most of the pyrenolichens, many of the squamulose, fo1iose and fruticose 1ichens and approximately ha1f of the Lichinaceae. Because the region is so diverse in habitats, ranging from fog-influenced coastal zones to alpine moun­tain tops and from deserts to subtropical regions, the lichen flora has proved exceeding1y diverse, constituting about 40% ofthespeciesknown in al!ofNorthAmerica. Thus, even though over 700 additional lichen species are treated in this volume as well as over 100 lichenicolous fungi, a third volume will be necessmy to complete the series.The decision to go to three vo1umes made it impossible to develop a comprehensive glossmy in this volume, because tenninology used by future authors cannot be fully antici­pated. In lieu of such a glossary,an extensive introduction to lichens was provided in beginning ofthe first vofume to faci1itate the use 6f the flora by begining lichenologists. An lndex to where the terms are discussed is provided in Vol. 1. A few terms specific to the 1ichenicolous fungi are defined at the begining ofthat treatment in this volume.