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In 1975, the contents of this web site were first published by Hafner Press (a division of Macmillan Publishing) as a book entitled California Mushrooms: A Field Guide to the Boletes. An invaluable help to anyone studying the boletes of the western United States, California Mushrooms was sorely missed when it went out of print in the mid 1980s. This web site puts the book back in print in online form as The Boletes of California.

To help you get the most out of this site, a few notes about the history of California Mushrooms and its conversion to The Boletes of California are in order.

The Author: Dr. Harry Thiers

A book doesn't spring into existence on its own; it is the result of the hard work of its author. The Boletes of California had the exceptional good luck to be written by Dr. Harry Thiers, an internationally respected mycologist who combines a depth of mycological knowledge with a willingness to describe and explain mushrooms to amateurs while providing the full details necessary for professional mycologists.

Dr. Thiers began his study of mycology under the tutelage of the pre-eminent mycologist Alexander Smith at the University of Michigan. He emerged with a Ph.D. in 1956 and headed south to teach at Texas A&M University. In 1959, he moved to California to take a position as professor of biology at San Francisco State University where he taught until his retirement in 1989. He remained at the university to run the Thiers Herbarium, the west coast's largest collection of fungal specimens, until 1994 when he retired and moved with his wife Ellen to Illinois.

Dr. Thiers is recognized as the world's leading authority on boletes, and has published eight books and over 50 articles about boletes and other mushroom families. In 1971, with co-author Alexander Smith, he published the thorough Boletes of Michigan. And in 1975, after extensive experience collecting and identifying California boletes, he published California Mushrooms. Since then he has edited an important series of monographs on California mushrooms entitled The Agaricales of California, culminating in the recent (1997) release of his monograph on the genus Russula.

Dr. Thiers has always been generous with his time for amateur mycology. He served as the scientific adviser for the Mycological Society of San Francisco for 30 years, has presented workshops on mushroom ID, led forays, and taught the public throughout North America. It is his involvement with amateur mushroom aficionados that leads him to write so compellingly about mushrooms for an audience that may be unfamiliar with the topic.

The Contents of California Mushrooms

In its original form, California Mushrooms contains a wealth of information about boletes. It starts with a section entitled "About Boletes" that examines the characteristics that make a mushroom a member of the family Boletaceae. It's an excellent introduction to boletes for amateurs and professionals alike. It then moves on to the heart of the book: a set of 85 species descriptions accompanied by keys for identifying those species using specimens at hand.

The species descriptions are full descriptions that include the micro- and macroscopic characteristics of the species, its habitat, and observations about the species. Of the 85 species described, several of them are species novae, species that were first identified and published by Dr. Thiers in California Mushrooms. Five of the 85 species are listed as extralimital, boletes that haven't yet been found in California but based on Dr. Thiers experience should, in all probability, exist here. Since publication of the book in 1975, some of these extralimital boletes have, indeed, been found in California.

California Mushrooms is unusual in the fact that it contains two distinct sets of keys. The first set of keys, the technical keys, may use characteristics that require special equipment (typically a microscope), materials (such as test chemicals), and procedures that most amateur mycologists may not be able to perform. The second set of keys, the field keys, uses characteristics that are much easier to determine, features easy to observe by eye while in the field. This dual set of keys allows readers to have their cake and eat it too. They can identify a specimen easily using the field key and then, if they have the necessary materials and knowledge for the technical key, nail that identification down in a manner acceptable to any professional mycologist.

To help readers envision the boletes described, California Mushrooms uses another unusual feature: it includes a single microfiche that includes 54 tiny color images of boletes best viewed in a microfiche reader. These bolete images are slides of bolete specimens collected and photographed by Dr. Thiers. The microfiche was a concession to the cost of color printing--it provided color images while keeping publication costs low enough for the publisher to bring out the book.

California Mushrooms finishes with a bibliography that lists pertinent mycology texts at the time of printing.

Creating an Online Version of California Mushrooms

Since the onset of the World Wide Web, Mike Wood has always had it in the back of his mind to bring back California Mushrooms in an online version. When the book went out of print in the mid eighties, the copyright reverted to Harry Thiers. Mike got permission from Dr. Thiers to put the book online, then began the conversion process.

The goal of conversion was to keep the meat of Dr. Thiers' book intact, adapting it to take advantage of computer and network technologies. These technologies provide advantages such as including color photos at little cost and creating keys whose elements are linked to other key elements and species descriptions. Mike's first step was to change the title of the work to The Boletes of California, a title that Dr. Thiers preferred but was changed by the publisher to the more general title California Mushrooms.


Mike turned the text of the original book into online text using a scanner and Optical Character Recognition (OCR) software, a process that often introduces "scanning typos." Mike did an initial pass to correct some of those typos, then turned the text over to Fred Stevens, who converted it to basic HTML. Once in HTML, Mike formatted each page to fit the design of the web site. He laid out the species descriptions to parallel the original book's descriptions. The pages then went to proofreaders Jane Wardzinska, Barbara Stevens, and Terri Beausejour, along with Fred and Mike, who took a second pass at the pages.


The keys provided a challenge and an opportunity: online keys can use links, which make keys much easier to use. Adding links, however, is a considerable amount of work.

Mike Wood assembled the keys from locations scattered through the original book, and put them into two main online keys: the technical key and the field key. He then laid them out in easily visible couplets and linked each line of the couplet to the next logical couplet or to a species description. He also created an alphabetic species list as a third and simpler method of access to the species descriptions.


Mike took the original microfiche to a professional scanning service to produce online images of each of the 54 boletes on the microfiche. The microfiche images are unfortunately somewhat blurry as a result of the low resolution of microfiche, and they have a distinctly red cast as well. Mike has tracked down some of the original slides used for the microfiche, scanned them, and replaced the microfiche images wherever possible. The images obtained from the original slides are of much better quality compared to the ones obtained from the microfiche. He's placed each image linked to the appropriate species description, and has added links to other online images of the same species if available.

Additional Material

An online version of a book requires a few additional materials--instructions for use, for example. And in some cases, a note or two about a major mycological change (a species name change, for example) since the book's publication. Mike Wood added brief notes where appropriate without revising existing material (this online version is an adaptation, not a revision) and created an additional bibliography of relevant papers that have been published after the 1975 publication of original book. Mike Boom wrote the text for "How to Use The Boletes of California" and wrote this foreword.


Structure is an important element of a content-rich web site. To make the material easy to access, Mike Wood divided the original book content into logical web pages. He created a page for each species description, and a page for each section such as "About Boletes" and the bibliography. He also created pages for the new material, then created a front page with organized links to each section and to the keys for further access. He added cross-reference links to pages where appropriate.


This site wouldn't exist without the work of many people. Primary among them is, of course, Dr. Harry Thiers for writing the original book. Following Dr. Thiers is Mike Wood, who managed the project, did the lion's share of the work, and paid for the web site. Fred Stevens was a major contributor, performing the primary HTML conversion. Mike Boom wrote additional online material. Jane Wardzinska, Fred Stevens, Barbara Stevens, and Terri Beausejour proofread scanned pages. On behalf of them all, we hope you enjoy the fruits of our labor.

-Mike Boom

The Boletes of California
Copyright © 1975 by Dr. Harry D. Thiers
Additional content for the online edition © 1998 by Michael Wood, Fred Stevens, & Michael Boom
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