Field guide to North American truffles : hunting, identifying, and enjoying the world's most prized fungi

210 Pages·2007·4.95 MB·English

by  Trappe

The information in this book is accurate to the best of the authors’ knowledge. However, neither the authors nor the publisher
can accept responsibility for mistakes in identification or idiosyncratic reactions to truffles or trufflelike fungi; people who eat
fungi do so at their own risk.
Text and photography copyright © 2007 by Matt Trappe, Frank Evans, and James Trappe.
All rights reserved. Published in the United States by Ten Speed Press, an imprint of the Crown Publishing Group, a division of
Random House, Inc., New York.
www.crownpublishing.com
www.tenspeed.com
Ten Speed Press and the Ten Speed Press colophon are registered trademarks of Random House, Inc.
Library of Congress Cataloging-in-Publication Data
Trappe, Matt.
Field guide to North American truffles: hunting, identifying, and enjoying the world’s most prized fungi / Matt Trappe, Frank
Evans, and James Trappe.
p. cm.
Summary: “A full-color illustrated guide to identifying North American truffles by their key features; includes profiles and
photographs of more than 80 species of truffles, as well as a delectability rating and culinary use tips for each species”<Provided
by publisher.
Includes bibliographical references and index.
1. Truffles—North America—Identification. 2. Truffles—North America—Pictorial works. 3. Cookery (Truffles) I. Evans, Frank.
II. Trappe, James M. III. Title.
QK617.T775 2007
579.5’7—dc22
2007015864
eISBN: 978-0-30780775-5
Cover and text design by Chloe Rawlins
All photographs by Matt Trappe, Frank Evans, and James Trappe unless otherwise indicated
v3.1
Acknowledgments
For many years, the North American Truffling Society (NATS) has made a
packet of truffle photographs available to its members to assist them in their
study of fungi that fruit belowground. In the process of updating the packet,
the concept for this book was born. The information in this book derives
from the earlier effort. We would like to acknowledge the long years of work
by Pat Rawlinson, who duplicated the photos many times, and Vern Moore,
who gathered and maintained the information sheets that accompanied that
packet.
The beauty and much of the value of this book is in the photographs. The
efforts of these photographers made it all possible: Mike Castellano, Todd
Elliot, Jonathan Frank, Roy Halling, Susan Hopkins, Dave Largent, Charles
Lefevre, Donna Mitchell, and Matt Smith. Mike Castellano and Efrén Cázares
reviewed the text and suggested many improvements. Much of the
information on fresh characters and distribution of the various species was
provided by members of the North American Truffling Society. All these
contributions combined to make the book more comprehensive.
Thanks!
Contents
Introduction to Truffles
What Are Truffles?
How to Find Truffles
Identification of Truffles
Culinary Safety
Truffle Names
Truffle Species Profiles
Glossary
Meaning of Scientific Names
References
Index
About the Authors
About the North American Truffling Society
Introduction to Truffles
Truffles have long enjoyed a mysterious appeal, not only to the mycologist
but also to a wider audience. These exotic fungi have been celebrated in
myth and lore as well as being worshiped by chefs around the world. The
Italian White (Tuber magnatum), the French Black (Tuber melanosporum),
and the summer truffle (Tuber aestivum) are world famous—the great
culinary truffles of the world. These truffles are only a few of the many
underground fungi to be found. Collectors encounter hundreds of other
species while searching beneath the forest floor. Indeed, the spring and fall
Oregon White Truffles (Tuber gibbosum and Tuber oregonense,
respectively) are considered by many to rank among the world’s great
culinary delights. This book includes only a sampling of the hundreds of
North American species. A few are indeed culinary delights, but most have
only modest attractiveness for cooking. All, however, are interesting and
important in our forest ecosystems.
Across North America, the temperate forest supports a wide range of
fungal species. Within this diversity are many belowground-fruiting species.
Until recently, this community of specially adapted fungi was known only to
a few mycologists. The references available for study of these truffles are
specialized or rare scientific books and papers. Only a few tangential
references to truffles and trufflelike species exist in most popular mushroom
books. This book is a first of its kind and will be of great help to all who are
interested in these underground jewels.
What Are Truffles?
A truffle is the spore-bearing organ (“fruit”) of a fungus. The actual fungal
organism is a perennial network of underground mycelium (fungal filaments
dispersed in the soil). Unlike mushrooms, truffles develop entirely
underground. Whereas mushrooms typically disperse their spores in the
wind, truffles need the help of animals to spread their spores. Most truffles
are consumed by forest animals that dig them up for food. It is no surprise
that truffles have evolved to emit aromas that appeal to animals, often
including humans. When mature, truffles produce these odor signals to
effectively say “eat me!” The aromas develop only when at least some spores
are mature, then intensify as more and more spores mature. Thus an animal
is not likely to detect a specimen before many of its spores are ready, and it is
not likely to miss a specimen in which all the spores are ready.
Truffle spores pass through the digestive system unharmed and are
deposited in feces to germinate and form new fungal colonies, often great
distances away from their “parent.” As a food source, they are an important
part of forest ecosystems; some small mammals (such as certian voles)
subsist almost entirely on truffles!
One defining characteristic of truffle-forming fungi is that nearly all form
symbiotic relationships with plants. This is a mutually beneficial partnership
in which the fungal mycelium and the root cells of the plant grow together
creating special structures with the roots called mycorrhizae (from Greek,
myco = fungus and rhiza = root). The plant shares the sugars it creates by
photosynthesis with the fungus, and the fungus assists the tree roots to take
up water, minerals, and other nutrients from the soil. The fungal mycelia are
much more efficient than unaided tree roots at foraging for nutrients; as
much as 100 meters of fungal hyphae (microscopic filaments of fungal cells)
can be found in a single teaspoon of healthy forest soil!
This symbiotic relationship is so important that very few tree species can
grow without their mycorrhizal fungi associates; many forest tree nurseries
now intentionally inoculate seedlings that will be used in reforestation with
mycorrhizal fungi. There are varying degrees of specificity in this symbiotic
relationship; truffles are always found in association with particular plants,
sometimes with only a single species of tree. Likewise, different trees have
varying numbers of fungi with which they will form mycorrhizae.
In parts of Europe, the term truffle is used to refer to only certain kinds of
belowground-fruiting fungi, sometimes only to species that are
commercially harvested. In this field guide we use the term in a broader
sense to designate all macroscopic fungi that fruit belowground. Most truffle
species are related to or directly descended from aboveground mushroom-
forming fungi, so it is no surprise that some belowground species look like
compressed mushrooms. Some examples of the latter are included in this
guidebook, for example, Gastroboletus, Macowanites, Rhopalogaster, and
Thaxterogaster.
How to Find Truffles
The first step in finding truffles is to find habitats with appropriate host
trees. All trees in the pine, oak, birch, and willow families, plus many others
in temperate climates, form mycorrhizae with truffle-forming fungi. Some
trees that rarely support truffle-forming fungi are arborvitae, cypress,
junipers, ash, maples, and most fruit trees.
Unless you have a trained truffle dog to sniff out your bounty, unearth
them with a rake that has three to five widely spaced tines (such as a garden
cultivator). Gently peel back the duff and rake lightly into the soil. Most
truffles are found just a few inches deep, at or very near the boundary
between the mineral soil and the forest litter—you don’t need to dig a deep
pit. Truffles will appear like little potatoes (usually between the size of a pea
and a golf ball) that look quite different from the surrounding soil. Once you
begin to learn the habits of the truffles in your area, you will have more
success. Remember to always push the duff back over the area you have
raked to help the habitat heal.
Typical appearance of freshly unearthed truffles.
To refine your technique, look around on the forest floor. Have the local
experts—the small animals—been creating little digs in the earth? This is
often an indication that there are truffles in the area. Squirrels and mice
usually unearth truffles one at a time, leaving a small pit; sometimes they
will nibble the upper part of a specimen and leave the lower part. Usually
they will dig up only a few of the specimens present, leaving others to
mature later. Once a pit is found, careful raking of several square feet of
surrounding ground to about the same depth as the bottom of the pit is likely
to yield specimens. Needles, leaf fragments, other debris, or spider webs in a
small animal dig usually indicate it is so old that further exploration will be
unprofitable. Tunnels usually are not closely related to occurrence of
truffles; if the bottom of a hole cannot be felt with a finger, it should not be
regarded as an indictor of truffles.
Low spots or areas adjacent to rotting logs often maintain more soil
moisture throughout dry times, creating a favorable habitat for fungi. Try
searching there. Some truffles prefer loose soil; others are found where the
soil is somewhat compacted or where the humus layer is thin. Under such
circumstances even relatively small specimens will hump up the humus
enough to be detected by a perceptive searcher, while large species may
emerge through the surface. Thus campgrounds, old tractor trails,
abandoned roads, and road banks are particularly productive places to look.
Because tree roots permeate the soil in forests, truffles potentially could be
anywhere. Sample different microhabitats to see where the truffles grow in
your forest. Generally, they are most numerous and diverse in places with
relatively little ground vegetation. Often the soil adjacent to rotten logs is
good, particularly the “microbenches” on the upper sides of long-fallen
trees lying along the contour of moderate slopes. Finally, random searching
can provide fine collections. Seemingly unlikely sites can harbor some
species that do not often occur elsewhere. In one instance, a splendid group
of Tuber specimens were discovered during cultivation of a rose garden in a
city residential area. The more you look, the better your odds of success;
hence the adage “The more the tines rake the ground, the more the truffles
will be found.” Truffle hunting is a matter of enthusiasm tempered with
patience, persistence, and a little luck.
When to Look for Truffles
Each species of truffle has its own fruiting season; most productivity
happens during the rainy season, but there is potential to find something
most any month of the year. If you are seeking a particular truffle, you will
need to consider its specific habitat requirements and fruiting season
tendencies. In temperate regions there is usually a flush of fruiting in spring,