Boletes of Eastern North America

Boletes of Eastern North America

alan e. beSSette, william c. roody, and arleen r. beSSette SyracuSe univerSity preSS

NOTICE: Although this book includes information regarding the edibility of the mushrooms described, it is not intended to function as a manual for the identification and safe consumption of wild mushrooms. Readers interested in consuming wild fungi should consult other sources of information, including experienced mycologists and literary works, before eating any wild mushrooms. The authors and the publisher are not responsible for any undesirable outcomes that may occur for those who fail to read or heed this warning. Copyright © 2016 by Syracuse University Press Syracuse, New York 13244-5290 All Rights Reserved First Edition 2016 16 17 18 19 20 21 6 5 4 3 2 1 ∞ The paper used in this publication meets the minimum requirements of the American National Standard for Information Sciences—Permanence of Paper for Printed Library Materials, ANSI Z39.48-1992. For a listing of books published and distributed by Syracuse University Press, visit www.SyracuseUniversityPress.syr.edu. ISBN: 978-0-8156-3482-9 (hardcover) 978-0-8156-1074-8 (paper back) 978-0-8156-5394-3 (e-book) libr a ry of congress cataloging-in-publication data Names: Bessette, Alan, author. | Roody, William C., author. | Bessette, Arleen Rainis, 1951– author. Title: Boletes of eastern North America / Alan E. Bessette, William C. Roody, and Arleen R. Bessette. Description: First edition. | Syracuse, New York : Syracuse University Press, [2016] | Includes bibliographical references and index. Identifiers: LCCN 2016038515 (print) | LCCN 2016039651 (ebook) | ISBN 9780815634829 (hardcover : alk. paper) | ISBN 9780815610748 (pbk. : alk. paper) | ISBN 9780815653943 (e-book) Subjects: LCSH: Boletales—North America—Identification. Classification: LCC QK629.B63 B47 2016 (print) | LCC QK629.B63 (ebook) | DDC 579.6/1632—dc23 LC record available at https://lccn.loc.gov/2016038515 Manufactured in the United States of America pp. ii–iii: Harrya chromapes p. xvi: Frostiella russellii facing page 1: Tylopilus felleus p. 12: Neoboletus luridiformis p. 22: Harrya chromapes p. 432: Hortiboletus rubellus p. 439: Tylopilus plumbeoviolaceus p. 440: Retiboletus ornatipes, gray form p. 456: Baorangia bicolor complex

• Generously supported by a gift in honor of Kevin William Pfeiffer •

We have been fortunate to be able to come to know and collaborate with many outstanding persons while working in the field of mycology. Dr. Roy E. Halling is one of those very special people. We dedicate this book to him with gratitude for his lifelong work and outstanding contributions to the field of mycology, especially in the area of boletology. Roy’s study and passion for mycology had a humble start with trips he took into the mountains of southern California as a Boy Scout. His first love was rock climbing, and through it he developed an interest in the flora of the region. Intending to major in forestry, he enrolled at California State University at Stanislaus, where he took a mycology course offered by Dr. David Gotelli. Roy began collecting macrofungi, taught himself the basics of mycology, and subsequently developed a specific interest in boletes. He continued his study of the Boletaceae with the eminent mycologist Dr. Harry Thiers at San Francisco State University, Dr. Roy E. Halling

viii completing his master’s degree in 1976 with a thesis titled “The Boletaceae of the Sierra Nevada.” Roy received his doctorate degree in 1980 from the University of Massachusetts, Amherst, supervised by Dr. Howard Bigelow. He then accepted a two-year postdoctoral position at Harvard University in the Farlow Herbarium. In 1983, he was offered and accepted the position of assistant curator of mycology at the New York Botanical Garden, where he currently holds the position of research mycologist and curator of mycology. While in New York, Roy began to shift his focus to the macrofungi of South America. He obtained a National Science Foundation grant to do a survey of the Collybia in South America. This survey began a fifteen-year collaboration with Dr. Greg Mueller to document the macrofungi of the oak forests in Costa Rica. Also in the 1980s, an opportunity to collect in Australia introduced Roy to the virtually unknown diversity of the boletes that existed there. He encountered boletes with combinations of features that transcended generic concepts as they were known in the Northern Hemisphere and thus began his fascination with the boletes of Australasia that continues today. Since then, Roy has worked intensively on the taxonomy and phylogeny of the fungi of Fraser Island and has collected boletes all over Australia as well as in New Zealand, New Guinea, Indonesia, Malaysia, and Thailand. In addition, Roy serves as adjunct professor of biology at City University of New York Graduate School and as adjunct senior research scientist with the Department of Ecology, Evolution, and Environmental Biology at Columbia University. He is actively involved in international collaboration with other specialists on the systematics, biogeography, and phylogeny of boletes, with particular emphasis in Australia and Southeast Asia. A prolific writer, Roy has published more than one hundred professional papers and more than fifteen abstracts. He has served as adviser for several doctoral candidates in the field of mycology; has held numerous editorial positions, including that of managing editor of Mycologia; and is a member of the Mycological Society of America (MSA) and several other prestigious mycological societies and associations. Roy also contributes his time, energy, and expertise to countless public services, from serving as chairman of the Nomenclature Committee of MSA to being on call with the Poison Control Center & Plant Information Service, appearing on National Public Radio’s program Science Friday, and routinely offering identification assistance and advice to the public at large. Roy is a past president of MSA and in 2006 was bestowed the honor of MSA fellow. There is so much to say about Roy and not enough space to do the telling justice. He is a gentle, kind man with a wry and offbeat sense of humor. When he speaks, there is a smile in his voice. When asked for help, advice, an opinion, or a thought, he unfailingly gives one his full attention and consideration. Roy’s

ix character and his love of mycology, the joy he takes in the theoretical and practical understanding of it, and the absolute lack of any personal ownership of it can best be described in his own words: “If there’s anything I can do to help, just let me know. . . . I am happy to share.” Thank you, Roy, for sharing your life’s work with so many.

Contents Preface xiii Acknowledgments xvii Introduction 1 The Bolete Fruitbody: Macroscopic Features 3 Information about Bolete Identification 7 How to Use This Book 13 Explanation and Use of the Field Keys 15 Field Keys to the Boletes 23 Descriptions and Illustrations of Bolete Genera and Species Alessioporus 55 Aureoboletus 57 Austroboletus 68 Baorangia 72 Boletellus 76 Boletinellus 81 Boletus 83 Bothia 171 Buchwaldoboletus 173 Butyriboletus 180 Caloboletus 185 Chalciporus 193 Cyanoboletus 200 Exsudoporus 202 Frostiella 206 Gyroporus 208 Harrya 215 Heimioporus 217 Hemileccinum 220 Hortiboletus 221 Imleria 226

xii · Contents Lanmaoa 228 Leccinellum 236 Leccinum 245 Neoboletus 275 Paragyrodon 280 Phylloporus 283 Pseudoboletus 287 Pulveroboletus 288 Retiboletus 296 Rubroboletus 301 Strobilomyces 305 Suillellus 309 Suillus 316 Sutorius 362 Tylopilus 364 Veloporphyrellus 405 Xanthoconium 407 Xerocomellus 414 Xerocomus 420 Undescribed Bolete Species Pending Publication 433 Appendixes A. Chemical Reagents and Bolete Identification 441 B. Microscopic Examination of Boletes 443 C. Collecting, Cooking, and Preserving Boletes 445 D. Common Tree Associates of Eastern Boletes 448 Glossary 449 References and Recommended Resources 457 Index to Common Names 461 Index to Scientific Names 463 Photo Credits 471

xiii Preface Because boletes are fairly large and colorful, and especially because many of them are excellent edibles, they are one of the most popular groups sought after by mushroom hunters. They are also important ecologically because of the mycorrhizal relationships they have with many different tree species. Our goal in writing this book was to provide a means to identify the majority of boletes found in eastern North America within the current context of accepted taxonomy. This book is not just a “redo” or update of North American Boletes (Bessette, Roody, and Bessette 2000). In the sixteen years since that book was published, many new American bolete species have been discovered, and major changes in bolete taxonomy have taken place. In our ongoing study and appreciation of boletes, we have learned much in recent years. This book includes these changes, additions, and corrections and presents them in a less-formal manner. We have restricted the species featured to those that are known to occur throughout eastern North America, extending west to Louisiana and north to Manitoba, Canada, providing more-focused and less-burdensome geographic coverage. A large number of new photographs, new information, and restructured field keys contribute to the ease of use for enthusiasts at all levels of expertise. With the ongoing process of molecular studies, construction of phylogenetic trees, and analysis of new data, many of the species currently placed in the genera we have listed will be transferred in the future to new or different genera. This is especially true for species currently in the genus Boletus. The process of erecting new genera to accommodate species in this very large genus and to some extent in other bolete genera has created a difficult issue for taxonomists, who must decide which genus name should be accepted. Some of the recently proposed genera are based only on macroscopic features, whereas others are based on microscopic characteristics or molecular analysis and the position of species in phylogenetic trees. As more and more DNA analysis of bolete species becomes available, it is uncertain which of the newly proposed genera will be changed and which will be retained. It is, however, quite likely that recently proposed new genera based only on macroscopic features will most likely be reassigned following DNA analysis. For example, Alfredo Vizzini, Giampaolo Simonini, and Matteo Gelardi (2014) erected the genus Exsudoporus to accommodate Boletus floridanus and Boletus frostii, two species that exude golden-yellow or amber-yellow droplets

xiv · Preface when young. The resulting new combinations are Exudoporus floridanus and Exudoporus frostii. A second example further describes the issue of retaining newly proposed genera based on macroscopic features. Alan Bessette and Orson K. Miller (2000) published Boletus rainisii. Gelardi, Vizzini, and Simonini (2014) erected the genus Cyanoboletus to accommodate several boletes with tissues that instantly discolor dark indigo blue when handled or bruised. One of the new combinations proposed was Cyanoboletus rainisii. In a subsequent publication, Noah Siegel, Christian F. Schwarz, and Jonathan L. Frank (2014) using DNA analysis, placed Boletus rainisii in the genus Xerocomellus and published the new combination Xerocomellus rainisiae. Recently proposed name changes based only on macroscopic features are briefly mentioned in the overview section of each description when necessary. By the time this book is published, it is quite likely that many more of these changes will have occurred. Although many scientific names have changed and more will be changed, the mushrooms themselves remain the same. No matter what name is used, the reader can always refer to the synonyms provided with each description or check other resources, such as Index Fungorum, to search for additional synonyms or to check for more recent name changes. To access Index Fungorum, use the link www.indexfungorum.org. Select “Search Index Fungorum” in the upper-right portion of the page. Make certain “name” is selected under “Search By” on the top left side of the new page. Enter the name of the genus and species you wish to research in the field provided under “Enter a search term.” Hitting “Search” will bring you to a screen that displays the genus and species name in blue type, the authority(ies) and the year it was published in black and in parentheses, respectively, and the currently accepted name in green. Clicking on the current name provided allows you to search Species Fungorum, which provides the current name, synonyms, authorities, and the year and publication site(s). Some previously accepted genera have been eliminated, and all of the species in those genera have been reassigned. Examples include Boletinus, Fuscoboletinus, and Gyrodon. In this work, species descriptions are preceded by genus descriptions. In most instances, the genus descriptions list the key macroscopic features on which the genus is based. Examples include Suillus and Tylopilus. In other instances, the genus is based on molecular or chemical analysis, and the number of macroscopic features listed may be significantly reduced. Examples include Imleria, Lanmaoa, and Retiboletus. Whenever possible, previously unpublished color images of the described species have been included. The known geographical distribution ranges for many of the species described have been expanded. We have modified species descriptions to include our personal observations of macroscopic features, macrochemical testing reactions, habitat information, edibility, and microscopic features when appropriate.

Preface · xv More interesting and exciting discoveries will be made in the future, a fact that keeps us happily engaged in the ongoing study of boletes. It is our hope that users of this book will benefit from its content and relaxed presentation, and will share our passion for this beautiful and fascinating group of mushrooms.

xvii Acknowledgments We could not have written this book without the help of so many friends and colleagues. It is with considerable pleasure that we acknowledge the following individuals who made so many valuable contributions. If we have failed to mention someone, please accept our apologies. Ian Gibson, Roy Halling, Paul Kirk, Shaun Pennycook, Scott Redhead, Tom Volk, and Nathan Wilson provided assistance with Latin nomenclature; Susan Mitchell and Glenn Freeman helped with specimen collecting, testing of the keys, and suggesting improvements to the manuscript. Bill Bakaitis, Charlotte Caplan, James Crane, Jonathan Frank, Roy Halling, David Hibbett, Harry “Whitey” Hitchcock, Mike Hopping, Geoffrey Kibby, Michael Kuo, David Lewis, Owen McConnell, Donna Mitchell, Mitchell Nuhn, Beatriz Ortiz-Santana, Igor Safonov, Noah Siegel, Matthew Smith, Walt Sturgeon, Barbara Thiers, and Bill Yule offered advice, raised questions that made us rethink some of our conclusions, assisted with identification, collected and photographed specimens for study, shared technical knowledge, provided resource information and/or molecular data, and researched unknown or undescribed boletes with us. Each generously shared his or her time and special expertise. For contributing photographs that greatly enhanced the functionality and beauty of this book, we are indebted to Bill Bakaitis, Harley Barnhart, Roy Halling, Mike Hopping, Josh Hutchins, Josh Kielsmeier-Cook, Michael Kuo, Renée LeBeuf, Owen McConnell, John Plischke III, Noah Siegel, Eva Skific, Mary Smiley, Walt Sturgeon, the “3 Foragers,” Greg Thorn, Andrus Voitk, and Bill Yule. Thanks also to David Lewis and Rosemary Williams for permitting us to include the images taken by the late Dan Guravich and Robert Williams. Copy editor Annie Barva’s sharp eyes, keen observations, and clear thinking guided us skillfully through the final manuscript preparation. We would have been lost without her. And to the Syracuse University Press director, Alice Randel Pfeiffer, and all of the staff at Syracuse University Press, a big “thank you.” We couldn’t ask for a better team to work with. If we were to name a “ghost writer,” that honor would go to Donna Mitchell. Not only did Donna collect and identify specimens necessary for this work, but she also continuously tested and pushed the limits of the field keys, read and critiqued the manuscript, sacrificed her time, and allowed her life to be disrupted

xviii · Acknowledgments by the travel and time away from home that this book demanded of us. Through the entire process, from that first phone call to explore an idea to this tangible book you now hold in your hands, she was quietly and steadfastly involved in every stage and step from start to finish. She held our feet to the fire, demanding the very best of us. Donna, there are not enough words to express our gratitude.

Boletes of Eastern North America

1 Introduction Of all the groups of wild mushrooms, none has engendered more enthusiasm and affection than the boletes. Their inherent beauty, their abundance, and, for many, their culinary appeal have firmly established boletes in the hearts of mushroom hunters around the world. The habitats, geographic distribution, and ecology of boletes—including the intriguing relationships they have with trees and shrubs—only add to their interest. As attractive and recognizable as boletes are as a group, individual species of boletes are not always easy to identify, making them a challenge for amateur and professional mycologists alike. Although some boletes are quite distinctive and easily recognized, others demand careful attention to details of the fruitbody and the habitat in which they appear in order to identify them with confidence. This book is an effort to facilitate the identification of the majority of boletes that occur in the eastern United States and Canada for those without the benefit of formal training in mycology. With the exception of the gilled boletes in the genus Phylloporus, all of the species featured in this guide fit the classic concept of a bolete as a fleshy mushroom having a typically cushion-shaped cap with a fertile layer consisting of vertical tubes beneath it and a stalk. Within this simple design are many variations in color, staining of the tissue when cut or bruised, cap surface, stalk ornamentation, flesh odor and taste, habitat, and growth pattern. The mycelium that is mostly hidden within the soil is another important component of boletes. Whereas the bolete fruitbody is a temporary structure in which the reproductive spores are produced and disseminated, the mycelium is perennial. It is made up of fine filamentous strands, called hyphae, that are typically concealed but may sometimes aggregate into a conspicuous “mycelial mat” at the base of the stalk. When visible, the color of mycelium is occasionally useful in identifying species. The mycelium of most boletes is united with the root system of the trees and shrubs with which it forms an interdependent, beneficial relationship. The fungus mycelium serves the tree or shrub by providing it with otherwise inaccessible moisture and nutrients such as phosphorus, nitrogen, and potassium. In turn, the tree or shrub provides simple sugars produced by photosynthesis that nourishes the fungus. This relationship is called mycorrhiza, an association that may be specific to certain groups of trees and mushrooms. Some

2 · Boletes of Eastern North America boletes form mycorrhiza only with conifers, others only with broadleaf trees. In some instances, the mycorrhizal association is host specific, meaning that the mushroom forms a unique union with a single species of tree. For instance, Leccinum luteum (p. 256) will be found only under American hornbeam (Carpinus caroliniana). It is now known that the majority of vascular plants form mycorrhizal relationships with fungal partners. This relationship is so important that some plants cannot survive independent of it. The health of entire ecosystems is determined by this cooperative interaction. For additional information about mycorrhizae, see Kendrick 2000 and Stamets 2005. Although the vast majority of boletes are presumed to form mycorrhiza with trees and shrubs, there are exceptions, such as Pseudoboletus parasiticus (p. 288), which invariably occurs attached to the fruitbody of the earthball, Scleroderma citrinum, on which it is thought to be parasitic. A few bolete species are nonmycorrhizal saprotrophs, growing on tree trunks or stumps or on the ground attached to buried roots. Some species of boletes commonly occur on decaying stumps and logs, suggesting that perhaps they are saprotrophs, but it is more likely that their mycelium has migrated to these substrates and that they are nonetheless mycorrhizal associates of nearby trees. Chemicals applied to the fruitbody sometimes provide color reactions that are valuable for differentiating some boletes. For certain species, we have provided macrochemical test reactions that are reliable, valid, and specifically diagnostic. These tests are mentioned in the descriptions. For additional information, see appendix A, “Chemical Reagents and Bolete Identification” (p. 441). Microscopic features of boletes are discussed in the species descriptions but are not utilized in the field keys for identification. For additional information about microscopic features, see appendix B, “Microscopic Examination of Boletes” (p. 443).

3 The Bolete Fruitbody Macroscopic Features Size and Stature The size and to some degree the shape of a bolete can sometimes be useful diagnostic features, particularly if specimens are unusually large or small. Cap diameters vary from 2 to 20 centimeters or more, though most boletes fall within the 6- to 12-centimeter range. Cap size in relation to stalk length and thickness may result in a stature that is tall and thin or short and stout or one of various other combinations. Regardless of overall size and stature, boletes generally have a characteristic cushion-like appearance that soon enables even beginners to distinguish them from other types of mushrooms even at a distance. Identifying individual species, however, is a much more formidable task, requiring careful scrutiny of each part of the fruitbody. The Cap Features of the cap are of primary importance in identifying boletes. There is a wide range of colors, but most are shades or blends of brown, gray, black, white, yellow, orange, red, or purple. Only occasionally are cap colors bright. More often they are softer earth tones. Although color is an obvious feature, it can be tricky. Not only is there some color variation within species, but cap color can change because of age, exposure to light, or other environmental influences. Surface texture may be glabrous, finely velvety, scaly, fibrillose, or glutinous. When fresh, it can be dry or moist, lubricous or viscid. Some caps may be uneven, pitted, or cracked—especially in age. Viscidity and the degree of cracking of the cap are affected by the weather. Caps that are normally viscid or glutinous when fresh become shiny and dry to the touch in dry weather, usually with particles of soil or other bits of debris adhering to them. Dry conditions also induce or exaggerate cracks and crevices in the cap, often revealing the flesh beneath. On some species, the cuticle extends beyond the diameter of the tube layer to form a narrow sterile band or sometimes flaps of tissue on the margin. Although the color of the flesh is usually white or yellow, it is pinkish or orange buff in some species. Instant staining of exposed flesh can mask the

4 · Boletes of Eastern North America original color. Pigments sometimes may leach from the cap surface and stain the flesh, but this discoloration is usually confined to the area just beneath the cap surface. For most boletes, the flesh is firm when young and becomes softer in age. Species in the genus Gyroporus have flesh that remains relatively hard and brittle, a useful trait in recognizing this genus in the field. The Tube Layer The tube layer of most boletes is easily separable from the cap flesh. This feature is often emphasized in distinguishing boletes from terrestrial polypores. However, there are some boletes, especially some species of Suillus, in which the tubes are not readily removed from the cap. The length of bolete tubes ranges from 2 to 20 millimeters or longer in large specimens. There are differences in how the tube layer is attached to the stalk. In some species, the tube layer may be squarely attached or depressed around the stalk. In others, the tube layer is decurrent and extends down on a portion of the stalk. The tubes and pores can be more or less evenly distributed, or they may be radially aligned. The pores may be circular to angular, irregular, or elongated. In the tube layer’s extreme expression, elongated pores have become gill-like, such as in Phylloporus rhodoxanthus (p. 286). Phylloporus rhodoxanthus

The Bolete Fruitbody · 5 The size of the pores range from 0.3 to 2 millimeters or larger. Young specimens of certain boletes have pores that are stuffed with mycelium, in which case the pores appear solid until the pores develop as the fruitbody matures. The color of the pores is used to distinguish groups of boletes. It can be white to gray, bright or dull yellow, dull pink to pinkish brown or dark brown, orange or red. The pores and tube walls are often concolorous, but in some specimens with dark-brown, red, or orange pores, the tube walls are typically paler. The color of the pores often changes as the bolete develops from a button to a mature specimen. The color often becomes duller or faded in age. Any staining or color change that is a result of bruising of the pores is also a very important feature. The Stalk The majority of boletes have central, straight stalks. There are exceptions, such as Boletinellus merulioides (p. 82), which typically has an eccentric stalk, and Boletus longicurvipes (p. 112), which has a stalk that is often curved near the base. Many boletes will have “situationally” curved stalks when they originate from somewhat vertical substrates such as a steep bank or tree stump. This curved shape is a geotropic response to properly orient the tube layer. The stalk may be approximately the same diameter throughout, enlarged at the apex and tapered downward, swollen in the midportion, or enlarged downward with a thickened or narrowed base. Most are solid, but a few, such as Suillus cavipes (p. 326) and Gyroporus species, have hollow or pithy centers. In addition to providing definitive characteristics, ornamentation on the stalk contributes greatly to the beauty of boletes. Reticulation found on many species of Boletus and Tylopilus species can be fine and delicate or bold and showy. For example, reticulation on the stalks of Boletus aureissimus var. aureissimus (p. 92) and Boletus nobilis (p. 121) is fine and delicate, whereas reticulation on the stalks of Frostiella russellii (p. 207) and Exsudoporus frostii (p. 205) is coarse, deep, and nearly lacunose. Many species of Suillus have resinous dots and smears, and species of Strobilomyces are woolly or shaggy. Leccinellum and Leccinum species are distinctive because they have stalks with scabers that give them a singed appearance. Some boletes have more subtly patterned or completely smooth and featureless stalks. When some species are young, especially Suillus species, their tube layer is concealed by a membranous, gelatinous, or cottony partial veil that extends from the cap margin to the stalk. As the cap expands, the veil ruptures, usually leaving a ring of material or a clearly defined ring zone on the stalk or sometimes remnants on the cap margin. The pores of some species of Suillus are covered by a false veil because the veil originates from the cap margin but never becomes integrated with the stalk tissue.

6 · Boletes of Eastern North America The base of the stalk is sometimes covered with yellow or red bristle-like hairs, the presence and color of which may be diagnostic, often serving as key identifying features—for example, Suillellus subvelutipes (p. 315). The stalk flesh is usually concolorous with the cap flesh, but the colors are sometimes, especially toward the base, intensified or altogether different.

7 Information about Bolete Identification Identification in the Field If you know the identification of a species and wish to read the description or see a color image of it, simply consult the index. If, however, you wish to identify an unknown bolete, follow the process presented here. Before attempting the identification procedure, try to collect specimens with different stages of growth whenever possible. The process of identifying boletes begins at the time of collection. The importance of recording field observations cannot be overstated. Because nearly all boletes grow in ectomycorrhizal partnership with certain trees, it is particularly important to note which tree species are involved. Some boletes form ectomycorrhiza with a broad range of trees, whereas others may be restricted to a single species. Ectomycorrhizal associations are obvious when boletes are found beneath isolated trees, such as in lawns or park lands, or when they appear among monotypic plantations or groves. In mixed woods, it is more difficult to pinpoint the tree partner, though it is sometimes possible to narrow the choices by knowing which trees are likely candidates. Trees that are prime ectomycorrhizal symbionts include the oaks, birches, beech, aspens and other poplars, hemlocks, pines, firs, and spruces (see appendix D, “Common Tree Associates of Eastern Boletes,” p. 448). Woodlands where these trees are well represented are the most rewarding places to look for boletes. The majority of boletes are terrestrial, but a few will fruit on tree stumps or, more rarely, on the trunks of living trees. Note whether the fruitbodies occur singly, scattered or in groups, or in clusters with their stalk bases united. Keep in mind that the more unusual a feature, either morphological or ecological, the more useful that feature is in making an identification. Other important field observations should include any color changes that occur on the fruitbody from bruising or handling. Bruising or staining of injured flesh, pores, or the cap or stalk surfaces is not characteristic of all boletes, but when it occurs, it is a very important diagnostic feature. Remember that staining reactions can be variable, depending on the species involved, the degree of maturation, weather conditions, and other factors. Staining reactions may also become less pronounced as specimens age and lose moisture after being picked.

8 · Boletes of Eastern North America The most commonly observed color change is the development of a blue to grayish-blue or greenish-blue staining reaction when the flesh is exposed to the air or when the pores are scratched or rubbed. Other staining reactions may be yellow, green, olive, red to reddish orange, vinaceous, brown, gray, black, or bluish black. Sometimes there is a succession of color changes on exposed flesh. If so, note the colors and the order in which they appear. To encourage staining of the flesh, cut the bolete in half lengthwise and then rub the exposed surface with the flat of a knife blade. A reaction can be instantaneous, or it may take several minutes or, occasionally, even up to a few hours. With some boletes, such as Suillellus subvelutipes (p. 315), the staining reaction is so rapid and thorough that it is difficult to ascertain the original flesh color. It is important to note that specimens used to determine staining reactions of the flesh should be fresh and unrefrigerated. Placing some bolete species in the refrigerator prior to examining their flesh for color changes may alter the test results. This is especially true for some species of Leccinellum and Leccinum. Staining intensity is also variable. The color change of Gyroporus cyanescens (p. 211) is dramatic. Its entire fruitbody quickly and decisively turns a rich, deep blue whenever it is bruised. In contrast, the flesh of Xerocomellus chrysenteron (p. 416) stains slowly and weakly. With some boletes, especially those that typically stain weakly, the reaction may be erratic, or in some collections the changes are so slight as to be almost imperceptible. Macrochemical testing of the fruitbody is best done on fresh specimens at the time of collection or soon thereafter. For additional information regarding macrochemical testing, see appendix A, “Chemical Reagents and Bolete Identification” (p. 441). Characteristic odors are not common among boletes, but they provide valuable clues when they are present. The strong, spicy odor of Suillus punctipes (p. 346), for instance, will readily and convincingly distinguish it from otherwise similar species. Taste can also be a very useful field character. The flesh of some boletes, especially those in the genus Tylopilus, is exceedingly bitter, whereas the flesh of others may have a distinctly nutty or sweet taste. Chalciporus piperatus (p. 195) has an unforgettable biting, acrid taste. The cuticles of certain species of Suillus have an acidic quality that the tongue is quick to discern. There is no danger in taste testing any bolete as long as you do not swallow your sample. Consumption of alcoholic beverages before taste testing the flesh of a bolete may alter or prevent detection accuracy. Recording an image of a fresh collection either with a camera or a sketchbook can be enormously useful for later referral, particularly if the specimens are likely to deteriorate before you can work on them. Boletes are highly perishable.

Information about Bolete Identification · 9 Once mature specimens are picked, they can very quickly turn into an unrecognizable entity. When taking a documentary photo of a bolete, be sure to show the upper cap surface, the pores (including a scrape to show any staining), and the entire stalk. A full-length section of the fruitbody as it appears immediately after cutting is also useful. If there is a tardy staining reaction on the cut flesh, a second photo is desirable to show the change. A sharp color photo or detailed drawing, in combination with good field notes, will enable you to identify a surprising number of boletes long after the actual specimens have been relegated to the compost heap or nearby woodlands. Identification at Home The use of field keys, such as those in this guide, may lead to successful on-thespot identifications of the more distinctive species. Many boletes, however, will require more careful, critical study, best done in the comfort of home or workplace with additional resources on hand. When bringing a collection of boletes in from the field or woodlands for further study, you should include, if possible, several examples to represent all stages of development. Many changes in color and structural appearance, such as a diagnostic cracking of the cap cuticle, can take place during the transition from a button bolete to a mature specimen. Refrigerate any specimens that are not to be worked on right away in order to keep them in favorable condition for a day or two. A mature specimen should be set aside to provide a spore print. Individual spores are too small to be seen without a microscope, but collectively they exhibit a colored deposit that is readily observed with the naked eye. Spore-deposit colors range from yellow to olive, olive brown, pinkish brown to reddish brown, pinkish to reddish pink, vinaceous, yellow brown, chocolate brown, or grayish brown to blackish brown. To make a spore print, cut the stalk squarely off close to the cap when possible, leaving about a one-half-inch stub to serve as a pedestal. To avoid any leaching of pigments from the cap or tubes, make sure the pores do not rest directly on the paper. Place the cap with the pore side facing down on a piece of white paper and cover it with an inverted bowl or similar object to restrict air currents. The spores will drop and form clusters of colored dots on the paper. It may take several hours for a sufficient spore deposit to form for color evaluation. Be sure to maintain a vertical orientation of the tube layer so that the spores can drop freely, especially if the pores are small. Although spore color is a defining characteristic for distinguishing several genera of boletes, it is not always necessary to make a spore print. With a little practice, you can recognize the genus of many boletes on the basis of macroscopic features of the fruitbody. However, with other boletes, spore ornamentation can

Making a spore print

Information about Bolete Identification · 11 be critical in determining both genus and species. Observation of this feature requires a microscope. Seen through a microscope, typical bolete spores are long and narrowly elliptical or spindle-shaped in face view and inequilateral in profile. For more discussion of microscopic examination of spores, see appendix B, “Microscopic Examination of Boletes” (p. 443).

13 How to Use This Book First and foremost, this book is intended to serve as a guide for the field identification of boletes. The keys and text reflect a minimally technical approach with emphasis on macroscopic features of the fruitbody as well as relevant ecological considerations. The species described and illustrated are organized alphabetically first by genus and then by species for easy reference. They are also organized this way because they share similar macroscopic and microscopic features that define the genus in which they are placed. In some instances, species have been renamed and transferred to a new genus based on their relationships as determined by DNA analysis. Because there are different interpretations of taxonomic status and thus the prioritized species names, it may be easier to locate species descriptions by consulting the index of scientific names, which includes synonyms. The numbers of known species indicated in the introductory matter for each genus may vary from those included in other sources because the numbers depend on which classification scheme one chooses to follow. Each species description begins with the currently accepted Latin name of the genus and species. This Latin name is followed by the name of the author(s) who first described the species and the name(s) of those who subsequently amended the nomenclature. Where there have been revisions, the name of the original author who first described a species is shown in parentheses followed by the name of the person or persons who made a change. For example, you will see Leccinum rubropunctum (Peck) Singer (p. 261). Charles H. Peck was the first to describe this species as Boletus rubropunctus and published it in 1897. Rolf Singer later concluded that this species should be reclassified in the genus Leccinum, so he transferred and published this new combination in 1947. The primary Latin names utilized in this book may vary from those commonly found in other contemporary publications that feature boletes. They reflect the most recent taxonomic trends based on molecular research. Although it is nearly impossible to keep up with the rapidly changing proposed names for mushrooms, we have relied heavily on Index Fungorum (www.indexfungorum.org), which is a perpetually updated source for the most widely accepted current names. Synonyms for species are provided in each of the descriptions. These names have been previously applied to species, many of which appear in recent books and taxonomic literature.

14 · Boletes of Eastern North America Each fully described species is accompanied by at least one color illustration. In many cases, more than one depiction is provided to demonstrate the considerable variation exhibited by many boletes. The definitions and terms used in this book are as nontechnical as possible, except where simpler definitions are inadequate or less precise, or when using the technical terms is unavoidable—as in the “Microscopic Features” section of each species description. Such technical terms are defined in the glossary. Dichotomous field keys provide a systematic method for identification of species or closely allied clusters of similar species. Although the keys have been prepared with the nonspecialist in mind, using them requires some familiarity with anatomical terms. Beginners are encouraged to review the section “The Bolete Fruitbody: Macroscopic Features” (p. 3). You should confirm your identifications by careful comparison with the written descriptions. There are many similar species, including some that do not appear in the key. Therefore, it is important to read the information provided in the “Lookalikes” section of each description. It is also a very good practice to “key-out” species whose identity is already known. This will enable you to become comfortable with the key’s language and to sharpen your skills of observation. Do not expect success with every attempt at identifying boletes. You may encounter a species that is undescribed or one that is not included in this work. In addition, characteristics of the fruitbody are often ambiguous, and photographs rarely show the full range of features or possible variations that you may encounter. The field mycologist must develop a measured sense of latitude, which sometimes crosses the line from the science to the art of identifying boletes.

15 Explanation and Use of the Field Keys The keys in this guide are based on macroscopic features of the fruitbodies and the ecological situation in which the described species occur. Although field keys are useful tools, they should not be used alone to achieve an identification. Keep in mind that field keys are artificial devices designed to arrange organic entities into tidy concepts with clearly defined margins. However, nature is not tidy, and nearly every feature is expressed within a generous range. Color determination is particularly deceptive. Success in identifying boletes requires a fair measure of flexibility when evaluating features. The art of field identification is recognizing the point at which flexibility exceeds credibility. Only experience and practice will sharpen the skills needed to correctly interpret morphological or ecological ambiguity. Trying to identify boletes can sometimes be difficult and frustrating. Bear in mind the words of the preeminent Swedish mycologist Elias Magnus Fries (1794–1878): “No genus has given me more trouble than that of the Boleti.” The fruitbodies of boletes are relatively simple structures consisting of a cap with a fertile layer of more or less vertical tubes beneath it (in the genus Phylloporus the fertile layer is decurrent and gill-like) and a stalk that elevates the cap and fertile layer in order to facilitate spore dispersal. Within this simple design, there are a limited number of field characters to consider. This limitation makes it challenging, if not impossible, to distinguish every bolete based solely on macroscopic features that may overlap or that exhibit only slight differences. When the field keys are used, too much detail can sometimes become more confusing than convincing in the attempt to separate similar species. In these situations, the couplets (paired numerical choices in a key) will terminate at a small cluster of species that share multiple features. Additional comments that attend the species in a cluster serve as cues or hints that may point to a more plausible determination. However, these observations are not necessarily unique and may also apply to others in the group, whether this is stated or not. At this juncture, turn to the full descriptions and photos to compare similar species in greater detail. Subtle differences that are difficult to convey linguistically are often readily apparent in a photograph. The keys are based on the features exhibited on young, fresh specimens in good condition. Older boletes may differ considerably in stature, cap surface texture, the presence or absence of veils, stalk ornamentation, and especially

16 · Boletes of Eastern North America fruitbody colors. Whenever possible, collections for study should include multiple specimens in various stages of development. When fresh young specimens are not available, consider probable characteristics of earlier development, particularly in relation to the color of the cap and pore surface. For example, what is only a trace of a color on a mature cap may have been the dominant color in youth. Pores that start out white often become yellow, pink, or brown as they age. When you are keying out mature boletes with pores in this color range, it may be worthwhile to try an alternative key to species that have white or pallid pores when young. Using the Keys To begin the identification process, review this section’s summary of the five groups of boletes, which are divided according to surface features of the stalk, and select the group that applies. Then proceed to the “List of Field Keys,” which provides page numbers you can use to access the applicable key. The keys are constructed of paired numerical couplets, each of which provides two options. Carefully read each choice and select the one that most accurately fits your specimen. In many cases, ambiguous features are accommodated in either choice of a couplet. Continue the process until you attain a tentative identification. At this point, turn to the species descriptions and photos to confirm that the conclusion reached by using the key is a correct identification. If at some point neither choice in a couplet appears to fit, you may have made an error at a previous couplet, or perhaps the bolete you are attempting to identify is not featured in this book. It is even possible that a collected species may be unknown to science and therefore undescribed. If you are unable to identify a bolete using this guide, try searching other references that describe boletes, including those that encompass regions beyond the boundaries of eastern North America. The distribution ranges for most fungi are imprecise at best. The Five Groups of Boletes Based on Features of the Stalk Ring Stalks A ring or annular zone that is present on the stalk of some boletes is the remnant from a partial veil that extends from the cap margin to the stalk and encloses the immature pore layer of young fruitbodies. As the cap expands, this veil ruptures and collapses, leaving a membranous or fibrillose ring on the stalk. Some other boletes have a universal veil that encloses the entire young fruitbody. This type of veil leaves a sheathing ring or distinct ring zone on the stalk where the veil ruptures as the fruitbody expands.

Explanation and Use of the Field Keys · 17 Net Stalks The net-like pattern (reticulation) is present on many bolete stalks. It can cover the entire stalk or only a fraction of the stalk, and sometimes it is present only at the very apex. Reticulation can be coarse or fine, bold or delicate. A hand lens is helpful to detect particularly fine or delicate reticulation. Ring Stalk Net Stalk

18 · Boletes of Eastern North America Resin Stalks This type of ornamentation exhibits resinous dots and smears on the stalk. It is composed of clusters of cystidia that acquire and often exude pigments as the fruitbody matures. The dots sometimes merge to form irregularly shaped smears or patches. These exudates are more or less tacky to the touch and may stain fingers from handling. They are usually pinkish cinnamon to reddish brown and become darker with age or on drying. In some cases, the dots are whitish at first and do not become pigmented or do so only in age. A hand lens may be required to see them. The scabers and punctations present on Rough Stalks (Key D) are similar in appearance to resin dots but are dry to the touch and nonstaining and tend to be erect. Resinous dots and smears are characteristic of boletes in the genus Suillus. Resin Stalk

Explanation and Use of the Field Keys · 19 Rough Stalks Rough Stalks include species that have dry scales (scabers) or pointed projections (punctae) on the stalk surface. Scabers are composed of clusters of cystidia that form erect, often pointed scales. Most scabers are pallid at first but soon darken to brown or blackish, giving the stalk a singed or scorched appearance. Unlike the dots on Resin Stalks (Key C), scabers and punctae are dry to the touch and do not stain fingers when handled. Scabers

20 · Boletes of Eastern North America Smooth and Miscellaneous Stalks This group includes all boletes with stalks that are completely smooth or variously patterned but that lack a ring, reticulation, resinous dots, scales (scabers), or punctae. Because there is considerable variation in stalk appearance within this group, stalk detail illustrations are omitted here. Punctae

Explanation and Use of the Field Keys · 21 List of Field Keys Key A Ring Stalks, p. 23 Key B-1 Net Stalks: pores at first white to cream-colored or gray, p. 26 Key B-2 Net Stalks: pores at first some shade of yellow, p. 29 Key B-3 Net Stalks: pores at first orange, tan, buff, red, maroon, brown to dark brown, or nearly black, p. 34 Key C Resin Stalks, p. 35 Key D Rough Stalks, p. 37 Key E-1 Smooth and Miscellaneous Stalks: pores at first white to grayish, buff, olive buff, or pinkish tan, p. 41 Key E-2 Smooth and Miscellaneous Stalks: pores at first some shade of yellow or olive buff, p. 45 Key E-3 Smooth and Miscellaneous Stalks: pores at first orange, red, maroon, cinnamon, buff, or brown, p. 51

23 Field Keys to the Boletes Key A Ring Stalks, p. 23 Key B-1 Net Stalks: with white to cream-colored or gray pores at first, p. 26 Key B-2 Net Stalks: with yellow pores, p. 29 Key B-3 Net Stalks: with pores some shade of orange, tan, buff, red, maroon, brown to dark brown or nearly black, p. 34 Key C Resin Stalks, p. 35 Key D Rough Stalks, p. 37 Key E-1 Smooth and Miscellaneous Stalks: with white, whitish, grayish, buff, olive-buff, grayish-olive, or pinkish-tan pores when young, p. 41 Key E-2 Smooth and Miscellaneous Stalks: with yellow to pale-yellow or olive-buff pores at first, p. 45 Key E-3 Smooth and Miscellaneous Stalks: with red to rosy-red or copperyred, orange, maroon, cinnamon-brown, reddish-brown, or coffeebrown pores, p. 51 Key A Ring Stalks The ring or ring zone present on the stalk of some boletes is the remnant of a partial veil that extends from the stalk to the cap margin and encloses the pore layer on young specimens, or it may be from a ruptured sheathing universal veil. As the cap develops and expands, the veil breaks and separates from the cap margin. A collapsed partial veil adheres to the stalk as a membranous ring or ring zone. Evidence of a partial or universal veil can sometimes also be seen as hanging fragments of tissue on the cap margin. All of the species keyed here exhibit an obvious ring or distinct annular zone on the stalk. The ring is usually persistent but may become less conspicuous or even disappear on older specimens. Most Ring Stalks are members of the genus Suillus. 1a. Cap tomentose to fibrillose or scaly → 2 1b. Cap glabrous or pulverulent, viscid or glutinous → 8

24 · Boletes of Eastern North America 2a. Mycorrhizal with larch → 3 2b. Mycorrhizal with pine, beech, or oak → 5 3a. Stalk soon hollow; cap dark brown to yellow brown, dry, suede-like to scaly, ring whitish to ochraceous or inconspicuous or disappearing with age but leaving a distinct annular zone → Suillus cavipes (p. 326) 3b. Stalk solid and remaining so → 4 4a. Stalk ring indistinct or lacking; cap dry, tomentose to fibrillose-scaly, pinkish purple to reddish purple; pores large, angular, and radially arranged when young, becoming gill-like and intervenose at maturity, decurrent, pale yellow becoming golden yellow and finally brownish yellow in age → Boletus paluster (p. 132) 4b. Stalk with a prominent gelatinous reddish to reddish-brown ring on the upper portion, the lower portion with viscid pinkish-red to pinkishgray fibrils over a yellowish ground color; cap with coarse grayish to reddish-brown scales or patches, viscid to glutinous beneath the scales or patches; pores angular, elongated, and somewhat radially arranged, yellow becoming dull yellowish brown, usually staining pinkish when injured → Suillus spectabilis (p. 353) 5a. Cap and stalk densely covered with shaggy, grayish to pinkish-gray or blackish scales; ring zone sometimes obscure; cut flesh soon staining orange red then black; typically associated with oak or beech but sometimes also with pine → 6 5b. Cap and stalk reddish to reddish brown or dull orange → 7 6a. Cap scales purplish gray to blackish; widely distributed → Strobilomyces strobilaceus (p. 309) 6b. Cap scales paler, pinkish gray to pinkish tan or pinkish brown; often in sandy soil, especially in coastal areas; mostly southern in distribution but also reported as far north as Cape Cod, Massachusetts → Strobilomyces dryophilus (p. 307) 7a. Cap red to purplish red or rose red, fading in age to buff or ochraceous, cottony-velvety, soon breaking into fibrils and soft, more or less flattened scales, revealing yellow flesh below; always associated with white pine → Suillus spraguei (p. 356) 7b. Cap dull orange to pale reddish brown, fibrillose-scaly; associated with pines other than white pine in oak–pine woods → Suillus decipiens (p. 330) 8a. Associated with broadleaf trees, especially oak; ring thick, gelatinous; sheathing nearly to the stalk base; cap buff yellow to golden yellow or ocher, becoming dingy yellow brown to reddish brown in age → Paragyrodon sphaerosporus (p. 282) (if cap yellow pulverulent, see Pulveroboletus ravenelii [p. 295]) 8b. Associated with conifer trees → 9 9a. Mycorrhizal with larch → 10

Field Keys to the Boletes · 25 9b. Mycorrhizal with pine, spruce, balsam fir, or hemlock → 13 10a. Pores often staining bluish or greenish when bruised; associated with native larch; cap glutinous to viscid when fresh, gluten colorless; ground color variable, from grayish to greenish gray or pale grayish brown to yellow brown or reddish brown → Suillus viscidus (p. 361) 10b. Pores unchanging or staining colors other than bluish or greenish when bruised → 11 11a. Pores white, becoming grayish white and then pale reddish brown, bruising purplish gray and then reddish brown; cap with a dark reddishbrown layer of gluten that covers the whitish ground color, fading to pale reddish brown or yellow brown in age → Suillus serotinus (p. 349) (see also Suillus bresadolae var. flavogriseus [p. 323], Suillus grisellus [p. 338], and Suillus viscidus [p. 361]) 11b. Pores yellow, yellowish, or yellow olive → 12 12a. Pores radially arranged, staining reddish brown; cap viscid to glutinous, dark to pale olive buff, yellowish to tan or olive tan; stalk with a viscid band-like ring; associated with introduced European larch → Suillus flavidus (not illustrated) (p. 336) 12b. Pores not radially arranged, pores staining brownish when bruised; cap glabrous, shiny, viscid to glutinous, color variable, orange yellow, dull red, red brown, reddish brown to dark reddish brown, or dark chestnut brown; occurring only with larch → Suillus grevillei (p. 335) 13a. Pores staining greenish blue when bruised; cap at first covered with a coating of sulfur-yellow powder, later somewhat felt-like, orange red to brownish red → Pulveroboletus ravenelii (p. 295) 13b. Pores unchanging or staining colors other than bluish or greenish blue when bruised → 14 14a. Pores radially arranged → 15 14b. Pores not radially arranged → 16 15a. Stalk viscid from a gelatinous veil; cap glabrous, glutinous when fresh, red to mahogany red, orange chestnut, or reddish brown, often developing black spots and streaks with age → Suillus glandulosus (p. 332) 15b. Stalk dry; cap smooth or somewhat wrinkled, obscurely innately fibrillose to glabrous, viscid, chestnut brown or rusty brown to red brown, fading to orange brown with age → Suillus sinuspaulianus (p. 351) 16a. Cap dark reddish brown to cinnamon brown or sometimes ochraceous; stalk ring large and glutinous with purplish tones on the underside; flesh white to pale yellow → Suillus luteus (p. 342) 16b. Cap yellowish to tan, ocher yellow, orange yellow, olive brown to grayish brown, or pinkish cinnamon, often streaked → 17 17a. Stalk ring thin and band-like; cap cuticle tastes acidic; flesh whitish to pale yellow to orange yellow; pores slowly staining pale reddish brown when

26 · Boletes of Eastern North America bruised or sometimes unchanging, also covered at first with a soft, cottony, yellow partial veil that is coated with gluten → Suillus acidus (p. 318) 17b. Stalk ring baggy, thick, and glutinous; flesh orangish, often marbled → Suillus cothurnatus (p. 328) or Suillus salmonicolor (p. 348) K ey B-1 Net Stalks, with White to Cream-Colored Pores at First The pores of the boletes keyed here often become yellowish or pinkish as they mature. If this feature is indefinite, refer also to Key B-2. 1a. Pores staining blue to bluish green or bluish gray → 2 1b. Pores unchanging or staining colors other than bluish when bruised → 3 2a. Cap whitish to buff or pale brownish when young, becoming dingy brown with rose tints with age; stalk reticulation slight when present and only at the apex; pore surface bruising greenish blue or bluish gray → Boletus pallidus (p. 131) 2b. Cap rusty brown to pinkish brown, becoming reddish brown to chestnut brown or rusty cinnamon with age, at times mottled dingy yellowish, often wrinkled to shallowly pitted; stalk reticulation prominent, covering at least half of the stalk, stalk whitish near the apex graduating to brownish below; pores bruising bluish gray at first and then ochraceous to brownish → Boletus subcaerulescens (p. 157) 3a. Pores staining variously when bruised (sometimes slowly) → 4 3b. Pores not staining when bruised → 10 4a. Stalk reticulation prominent, coarse or fine (use a hand lens), covering one-third or more of the stalk → 5 4b. Stalk reticulation weakly expressed or limited to near or at the apex only → 8 5a. Cap pale to dark gray; stalk coarsely reticulate, whitish with deep yellow or reddish stains at the base → Retiboletus griseus (p. 297) 5b. Cap some shade of brown, reddish brown or maroon or with purplish tones → 6 6a. Flesh taste bitter or astringent; reticulation brown → Tylopilus felleus (p. 375), cap pinkish to reddish purple when young, soon becoming some shade of brown with or without purplish tints and finally brown to tan in age; pores becoming pinkish, vinaceous, or pinkish tan in age, often staining brown when bruised Tylopilus variobrunneus (p. 400), cap dark olive brown to greenish brown or blackish brown when young, becoming nearly glabrous and dull medium brown to chestnut brown; pores becoming yellow brown

Field Keys to the Boletes · 27 to brownish pink in age, staining brown to brownish rose or pinkish cinnamon when bruised; stalk reticulation whitish on the upper portion when young Tylopilus tabacinus (p. 398), cap yellow brown to orange brown or tobacco brown, becoming finely cracked in age; pores whitish or sometimes brown at first, becoming brown to yellow brown, with darker-brown patches and stains 6b. Flesh taste mild and pleasant or only slightly bitter → 7 7a. Cap reddish brown to dark rusty brown, typically wrinkled or shallowly pitted → Boletus pseudopinophilus (p. 137) (compare with Boletus chippewaensis (p. 98), Xanthoconium affine (p. 409), and Xanthoconium purpureum (p. 412) 7b. Cap yellow brown to orange brown or tobacco brown, becoming finely cracked in age; pores whitish or sometimes brown at first, becoming brown to yellow brown, with darker-brown patches and stains → Tylopilus tabacinus (p. 398) (see also Tylopilus variobrunneus [p. 400]) 8a. Cap and stalk white to whitish, developing dingy-brownish to yellowishbrown stains when handled; stalk weakly to distinctly reticulate → Tylopilus intermedius (p. 382) 8b. Cap or stalk more highly colored → 9 9a. Pores becoming yellow to rusty ochraceous with age → Xanthoconium affine (p. 409) and Xanthoconium purpureum (p. 412) 9b. Pores becoming pinkish or brownish with age → Tylopilus appalachiensis (p. 367), cap yellow brown over the disc, fading to pale yellow brown to dull tan on the margin or darker brown overall, at times with an orange or grayish tinge Tylopilus balloui (p. 374), cap at first bright orange to bright orange red, fading to dull orange, cinnamon, or tan in age; pores white to dingy white, becoming tan or slightly pinkish in age, staining brown when bruised Tylopilus alboater (p. 366), cap nearly black, velvety, often with a whitish bloom when young; pore surface bruising red and then black (see also Tylopilus atronicotianus [p. 369]) Tylopilus indecisus (p. 380), cap and stalk brown, reddish brown, or maroon or with purplish tones; pores becoming pinkish or brownish with age, staining brown when bruised (see also Tylopilus ferrugineus [p. 377], Tylopilus badiceps [p. 371], Tylopilus plumbeoviolaceus [p. 388], Xanthoconium affine [p. 409], Xanthoconium purpureum [p. 412], Tylopilus variobrunneus [p. 400], and Tylopilus rubrobrunneus [p. 395]) 10a. Stalk reticulation prominent, coarse or fine, covering upper third or more of the stalk → 11

28 · Boletes of Eastern North America 10b. Stalk reticulation limited to apex; cap and/or stalk with purple, violet, or lilac tones → 19 11a. Cap and stalk predominantly white, whitish, pale yellow, or grayish white → 12 11b. Cap and/or stalk more highly colored → 14 12a. Stalk reticulation deep with raised ribs, appearing pitted; pores white to grayish and sometimes beaded with clear droplets at first, becoming pinkish at maturity → Austroboletus subflavidus (p. 71) 12b. Stalk reticulation fine or coarse but not with raised ribs or appearing pitted → 13 13a. Flesh taste bitter; cap white to whitish, often with buff, pinkish, or pinkish-tan tinges or sometimes becoming grayish tan, pinkish brown, or golden brown overall with age → Tylopilus rhoadsiae (p. 391) 13b. Flesh taste mild or not distinctive; cap milk white to grayish white, sometimes with yellowish or brownish tinges, especially near the margin → Boletus albisulphureus (p. 86) (see also Retiboletus griseus [p. 297]) 14a. Cap and stalk with purple, violet, or lilac tones; cap color variable from creamy white tinged with lilac to pinkish brown, lilac brown, reddish brown, or sometimes dark purple, often paler near the margin and becoming yellowish brown to almost bronze-colored in age, often pitted, wrinkled, or lumpy and uneven → Boletus separans (p. 153). 14b. Cap and stalk lacking purple, lilac, or violet tones → 15 15a. Stalk with a wide band of yellow or golden yellow near the apex; cap pale brownish yellow to orange yellow, becoming yellow to bright yellow with a paler disc in age → Boletus gertrudiae (p. 108) 15b. Stalk lacking a distinct yellow band near the apex → 16 16a. Associated with conifer trees, especially Norway spruce; cap brown to cinnamon brown or rusty red to tan, often tacky to the touch, smooth or somewhat uneven, and slightly pitted → Boletus edulis (p. 101) (see also Boletus variipes [p. 167] and Tylopilus felleus [p. 375]) 16b. Associated with broadleaf trees, especially oak or beech → 17 17a. Stalk reticulation brown to blackish on mature specimens → Boletus atkinsonii (p. 89), cap grayish brown or yellowish brown, minutely cracked in age; stalk dingy white with fine brown reticulation; flesh taste somewhat nutty-sweet or not distinctive (see also Boletus variipes [p. 167] and Tylopilus tabacinus [p. 398]) Tylopilus minor (p. 384), cap pale brown to brown or dull whitish, often with pinkish tones, typically small, 3–8 cm wide but sometimes up to 15.5 cm wide; stalk whitish at first, becoming brownish to cinnamon with reticulation near the apex or extending to the midportion or sometimes lacking, with white basal mycelium; flesh taste bitter

Field Keys to the Boletes · 29 Retiboletus griseus (p. 297), cap pale to dark gray, stalk coarsely reticulate, whitish with deep yellow or reddish stains at the base 17b. Stalk reticulation white → 18 18a. Cap typically pitted to corrugated, yellow brown to deeper vinaceous brown; stalk club-shaped to distinctly bulbous, reticulation consisting of elongated meshes, strongly raised in places; reported from New York and New England, west to Minnesota, but distribution range yet to be determined → Boletus nobilissimus (p. 123) 18b. Cap usually smooth or cracked; stalk reticulation fine to somewhat coarse but not with elongated meshes → Boletus nobilis (p. 121), cap usually smooth but at times somewhat pitted, yellowish brown or reddish brown at first, becoming ochraceous to olive ochraceous or reddish ochraceous with age Boletus variipes (p. 167), cap smooth to somewhat pitted at first, often developing cracks or fissures, color variable, creamy tan to yellowish tan, grayish brown to yellow brown or dark brown (see also Boletus atkinsonii [p. 89]) 19a. Cap brownish to grayish brown or dull cinnamon, at times tinged with purplish areas; stalk purple with white mycelium at the base when young, at times becoming grayish purple or purplish brown → Tylopilus plumbeoviolaceus (p. 388) 19b. Cap grayish violet to bluish violet when young, becoming pale purplish, purplish pink, or tan to dull brown in age, staining rusty violet to dark violet when bruised; stalk concolorous with the cap or paler when young, becoming brown in age, with a white apex and base → Tylopilus violatinctus (p. 402) Key B-2 Net Stalks, with Yellow Pores Note: Several boletes have pores that are white when young but then become yellow with age. If this feature is uncertain, refer also to Key B-1. 1a. Pores staining blue, greenish blue, or blackish blue when bruised (sometimes weakly or slowly) → 2 1b. Pores unchanging or staining colors other than blue, greenish blue, or blackish blue when bruised → 16 2a. Cap whitish to dingy white with or without pinkish tones when young, becoming brownish with age; stalk yellow in the upper portion, pinkish to red in the lower; flesh bitter tasting → Caloboletus inedulis (p. 191) 2b. Cap more highly colored at first → 3