The North American Slime-Moulds: A Descriptive List of All Species of Myxomycetes Hitherto Reported from the Continent of North America, with Notes on Some Extra-Limital Species

In Short

This volume serves as a comprehensive, systematic survey of the Myxomycetes—or slime-moulds—found across North America. It acts as an essential botanical reference, meticulously detailing the morphological characteristics, distribution, and classification of these unique, often misunderstood life forms. By documenting the myriad ways in which these organisms manifest, the author provides a grounded, scientific framework that has helped stabilize the study of a group long plagued by shifting definitions and taxonomic debate, securing its place as a cornerstone for naturalists and mycologists alike.

The Story

The narrative of this work is one of rigorous biological categorization, tracing the identity of organisms that defy easy labels. It begins by confronting the fundamental ambiguity of the Myxomycetes: are they plants or animals? The author refuses to accept the simplistic "dictum" of contemporary experts, instead favoring the careful, observational approach of pioneers like DeBary. Through a dense, structured examination, the book moves from the general, philosophical problem of classification into the specific, physical reality of the organisms themselves.

The core of the study is a methodical descent into the various families—the Physaraceae, Didymiaceae, Stemonitaceae, and beyond. Each section functions as a field guide and a ledger. The author presents the reader with precise identification keys, allowing one to distinguish between species based on subtle variations in spore shape, capillitium structure, and the presence or absence of lime. The text is not a linear drama, but rather a cumulative argument for order. It charts the geographical reach of these species, noting their presence from the shores of Iowa’s Lake Okoboji to the mountain ranges of Colorado and the Pacific Coast.

As the book progresses, it addresses the "extra-limital" species, expanding the scope to ensure the North American list remains globally relevant. The author does not shy away from the frustrations of taxonomy, openly discussing the errors of his predecessors, such as the inconsistent naming practices of European naturalists, and correcting the record where previous documentation has been messy or misguided. The ending is not a final revelation but a testament to completeness; the extensive indices and corrigenda reflect a desire to leave the field of study in a state of stable, transparent organization. It concludes by reinforcing that while the slime-mould remains a puzzle, it is a puzzle that yields to the "patient investigator" who respects the nuance of nature’s smallest, most elusive architects.

How It Unfolds

The philosophical threshold The work opens with an intellectual defense of the slime-mould as an independent, well-defined group, rejecting any forced association with sponges or monads. The author establishes that the study of these organisms remains a vital, albeit challenging, domain for the botanist.

The anatomy of the minute Moving into the descriptive lists, the author provides detailed keys and technical specifications for each family of Myxomycetes. These sections act as a technical manual, defining the physical boundaries that distinguish a Physarum from a Badhamia or a Stemonitis.

The geographical survey The text spreads its net wide, documenting specific findings from across the North American continent. It links local observations in Pennsylvania or New England to their counterparts in Europe or Java, grounding theoretical taxonomy in physical, collected specimens.

The final clarification The closing chapters and supplemental lists address the inevitable errata of such a massive project. By refining the nomenclature and correcting past oversights, the author ensures that the taxonomy is as accurate as possible for those who follow in his footsteps.

The People

The book is primarily a dialogue between the author and the community of naturalists who preceded him. The author himself serves as a steady, authoritative guide who demands evidence over opinion. He frequently invokes the names of figures like DeBary, whose "painstaking investigations" into the life cycles of these organisms set the gold standard for the author’s own methodology.

Then there are the collectors and peers—men like Bethel, Bilgram, and Dr. Rex—who provided the "western-American variations" and "gatherings" that fill the book’s pages. The author treats their contributions with a mixture of professional gratitude and critical scrutiny. When he encounters a name or a classification he finds lacking—such as those proposed by Rostafinski or early European writers—he does not hesitate to challenge them, restoring original names when priority dictates and rejecting "happy" but inaccurate theories. These individuals are not characters in a play, but the collective mind of a science in flux. They are the eyes in the field, and the author is the final arbiter who weighs their findings, ultimately shaping their scattered observations into a cohesive, enduring archive.

In Its Own Voice

"No one test can be applied as a universal touchstone to separate plants from animals."

This is the author’s central argument regarding the fundamental nature of the Myxomycetes.

"These children of nature, which arise from an unformed jelly and an invisible seed, are able, as they gradually develop and allow their seemingly negligent formation to be closely observed, just as much as the most beautiful plant, to provide a sensitive heart with deep respect."

This quotation from A. J. G. C. Batsch captures the wonder the author feels for the subjects he is cataloging.

What It's Really About

At its heart, this book is an inquiry into the limits of human classification. The slime-mould represents the biological "edge case," an organism that refuses to conform to the neat binary of plant or animal. The author argues that biological reality is more complex than any "dictum" or "universal touchstone" can capture. It is a work about the necessity of humility in the face of nature’s fluidity. By documenting these organisms, the author is not just naming things; he is arguing that scientific knowledge is a collaborative, ongoing process of refinement. He posits that we must respect the physical evidence over the desire for theoretical simplicity, suggesting that the beauty of nature lies in its refusal to be easily pinned down.

Why Read It Today

This book is a deep dive for the patient reader—specifically the amateur naturalist or the student of biological history who finds joy in the meticulous. It is not a casual read; it is dense, technical, and heavily reliant on the nomenclature of a bygone era. Readers who love the tactile feeling of an old-school, grounded scientific pursuit will find much to admire here.

There is a strange, quiet beauty in the way the author describes a "sooty" slime-mould on a rotting elm log or the "iridescent-blue" of a rare sporangium. It feels like a window into the mind of a scientist who spent his life looking closely at the forest floor. The challenges are real: the Latinate terminology and the specific 1920s taxonomical debates can feel alien, and the period-specific scientific attitudes are evident throughout. However, for those interested in how we come to know the natural world, or for the reader who appreciates the transition from romantic wonder to rigorous modern observation, the experience is rewarding. It stays with you as a testament to the idea that there is profound value in cataloging the small, the overlooked, and the seemingly insignificant.