Gary E. Dillard:

Common Freshwater Algae of the United States

An Illustrated Key to the Genera (excluding the Diatoms)

1999. 1. edition, 173 pages, 298 figures, 16x21cm, 350 g
Language: English

ISBN 978-3-443-50026-9, spiral bound

out of stock - new edition available

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Synopsis top ↑

This manual has been prepared to provide beginning students and less experienced professional aquatic biologists a means to identify some to the more commonly encountered aquatic freshwater algal genera of the United States.

Keys, representative illustrations and general ecological notes are provided for some 300 genera, excluding the diatoms. Though there are many excellent taxonomic treatments of freshwater algae, most require detailed familiarity with algal morphology to use the identification keys successfully. To the extent possible, formal terminology common to most taxonomic treatments has been avoided in the preparation of the keys included in this manual.
An extensive bibliography provides references to more detailed taxonomic treatments for those who wish to proceed to species identification. Our concepts of the algal Classes, Orders and Families, due to new information largely provided by electron microscopy and molecular biology, are presently in a state of change.
The manual therefore does not include placement of the genera into supra-generic taxa, but the bibliography includes references providing such information.

Audience: students, professional aquatic biologists, anybody interested in the phycology of the freshwaters of North America

Rev.: Acta Botanica Hungarica 43 (1-2), 2001, p. 220-221 top ↑

This book is unusual in some respect. In the phycology it is unusual to publish an identification book only for genera and not more in the traditional taxonomic classification of algal groups. The author explains us the purpose of the book: "I have offered an upper-division/graduate level course on biology of the algae over a period of years, the laboratory component of which is devoted largely to the study of fresh field collections requiring students to identify algal forms to genus, learning their most important diagnostic features in the process. The students enrolled in the course have rarely had sufficient introduction to the morphology of freshwater algae, making it virtually impossible from the beginning of the laboratory sessions for them to use published keys and descriptions to achieve identification of the algal forms encountered in the collections. This manual is an attempt to provide such a reference, providing keys that are, in common parlance, "user-friendly", in that technical terms with which students are initially unfamiliar are avoided insofar as possible."

Therefore the reader/user of this book do not find here the traditional ("phylogenetic") classification of different algal phyla, classes, etc. After a short introduction ("statement of purpose"), brief presentation of algal habitats, methods of collection and the use of dichotomous keys, the main chapter of the book is the "key".

All genera are distributed to nine "section" (macroscopic - grass-green, erect, differentiated into a stem-like axis and "leaves"; microscopic - unicellular flagellated; unicellular non flagellated; colonial flagellated; colonial non flagellated; filamentous unbranched; filamentous branched; pseudoparenchymatous and coenocytic or sac-like tube forms). All section have its key, a short description of morphological characteristics of genera, with a few drawings showing the different types of forms (species - not written an exact species name). Unfortunately there are several genera without any drawings, which could be determine with difficulty. Altogether 345 genera are included in the book.

Keys are clear and it is easy to follow them and to identify a genus. Because the "sections" are "unnatural", there are genera together in one section of different traditional algal groups. For the users it is not disturbing, but I think it would have been better and very useful to write the name of algal division, or class, or order of genus in question where it belongs to.

I recommend this unusual but useful book for all phycologists, algologists working on freshwater algae all over the world and I recommend it first of all for young colleagues who starts to investigate freshwater algae.


Acta Botanica Hungarica 43 (1-2), 2001, p. 220-221

Rev.: Journal of Phycology, 36,3,(2000) top ↑

This is a beginning key to common freshwater algae of the United States exclusive of diatoms. The key is constructed with minimal terminology to allow use by beginning students and the phycologically challenged. It is not "natural" and does not place the genera into higher taxonomic categories. Dillard's key is similar to How to Know the Freshwater Algae by G. W. Prescott, except it does not include a glossary (a taxonomic list of genera, families, and orders) and provides less ecological information on algal genera.

Prescott's key includes the diatoms, but the section is weak, perhaps Dillard was wise to leave out the Bacillariophyceae. Dillard's numerous line drawings are clear and well reproduced. The use of genus names only to label the illustrations is a good idea. Otherwise, students often think they know the species name if it is given under one picture in a generic key. The book is a spiral-bound paperback that probably will survive a semester of Phycology laboratory.

Walter Dodds, Division of Biology, Kansas State Univ., Manhattan

Journal of Phycology, 36, 2, 2000

Journal of the Kentucky Academy ofScience, vol. 62(1),p.78 top ↑

Professor Gary E. Dillard put together this book after many years of teaching courses on the biology of algae at Western Kentucky University. His students were required to identify genus algae from field collections. He found that students had difficulty using published keys and descriptions because of their lack of familiarity with the technical terms used in these keys to describe algal morphology. He set out to produce this "user friendly" manual, which avoids as much as possible discipline specific language. His goal has not been fully accomplished; there is still much technical jargon in the book. The beginning student is unlikely to be familiar with terms such as lorica, epicene, hypocone, dendroid colony, and others found throughout this manual. A simple glossary would have been a most useful addition. Yet, this is the first simplified key to freshwater algae to be published since Prescott's Hour to Know the Freshwater Algae (1978), which today is hard to obtain.

The book starts with a statement of purpose and a definition of "algae" as representing a heterogeneous assemblage of oxygenic photoautotrophs that lack tissue differentiation and contain chlorophyll a. Based on this definition, algae include prokaryotic groups (the cyanobacteria and chloroxybacteria) as well as a wide variety of phylogenetically unrelated eukaryotic groups. In this section the traditional and modern systems of classification are briefly mentioned. Since the purpose of the book is to act as a key to identify algae only to the generic level, Dillard did not find it necessary to place the genera into higher categories (division, classes, orders). By doing this he also avoids discussing the recent dramatic and sometimes confusing changes in algal classification. This first section of the book calls at- tention to the extensive bibliography for those readers interested in phylogenetic relation ships among the algae or in proceeding to species identification. The next section, on algal habitats and collection methods, describes how to obtain qualitative samples with, for example, plankton nets or artificial substrates, for the purpose of conducting a survey of algal forms. There is no description of standard quantitative methods.

The rest of the book is divided into nine sections where genera are grouped by artificial characteristics such as presence of flagella. By this system phylogenetically related tuna may not cluster together. The sections are I: Charales, plant-like genera; II unicellular flagellated genera; III: unicellular, non-flagellated genera; IV: colonial, flagellated genera; V: colonial non-flagellated genera; VI: unbranched filamentous genera; VII: branched filamentous genera; VIII: pseudoparenchymatous genera; and IX: coenocytic\ or sac-like genera. Within each section, the dichotomous keys to the genera are easy to follow, and each genus is illustrated with a detailed drawing. This manual excludes diatoms and many genera that occur largely in soil or aerial habitats.

Although the title of the book indicates that it deals with algae "of the United States," most genera of algae are cosmopolitan in distribution and the book can find users worldwide. There is a growing global denying for identification of freshwater algae. This demand is no longer restricted to academic circles and phycology classes. Identification of algae is a skill valued by drinking-water utilities whose operators are concerned with the presence of possible taste-, odor-, or toxin-producing species in their source water. It is also valued by environmental regulatory agencies that use algae as water quality indicators. Recently the U.S. Environmental Protection Agency (EPA) has added algae to its "Candidate Contaminant List" (CCL). This will increase the demand for the identification of algae. Like the students enrolled in the author's algae class, most people needing to identify common freshwater algae lack knowledge of the technical jargon. Many of them currently use "picture keys," particularly color charts available from the EPA that even have species names (not just genera) often associated with a pleasure. This commonly leads to misidentifications since the important diagnostic features are not learned when one does not follow a written key. The publication of this manual is timely. It will be useful to ens one needing to identify common freshwater algae to genus.

Journal of the Kentucky Academy of Science, vol. 62(1),p.78

Rev:ASB Bulletin 47(4), December, 2000 top ↑

Training students to identify specimens of freshwater algae makes one painfully aware of the common shortcomings of the standard keys. The available offerings have been either costly, overly inclusive and technical for a field course targeted to ecologists, or seriously outdated for a modern phycology course. Dillard's new text is a welcome addition to the usual choices, primarily because it makes the study of algae readily accessible to students in field intensive classes like limnology or aquatic ecology in addition to those students in a more traditional phycology course.

This "user friendly" approach is accomplished primarily by describing new terms only when they are first used, and minimizing specific terminology overall. Users of Prescot's 1978 How to Know the Freshwater Algae will immediately recognize that Dillard retained much of what worked in the past. In common with Prescott, Dillard's key is spiral bound, starts with an initial key to a few main sections (9 in Dillard's), is nicely illustrated with line drawings, and follows a taxonomy based on distinct morphology instead of a natural, phylogenetic system.

Dillard adds many helpful ecological and systematic notes in descriptions of the 300+ genera covered. In addition to an easy-to-use key, there is an overview of collection techniques and a bibliography of 66 taxonomic works related to the freshwater algae, all in a mere 173 pages. While the slim size of this very workable key is attractive, most instructors using this key for a survey course will find that they will need to add a variety of supplemental handouts. There is no glossary, nor any descriptions of the major algal taxa above genera. An index to terms could improve the utility of this key to undergraduates without cluttering up the text. Dillard's omission of the diatoms is somewhat forgivable in that it greatly simplifies the keys, and several good keys specific to the diatoms are available. I would have preferred, however, that some description of the diatoms with a few illustrations would have been included if only to help the neophyte recognize their distinctive differences. Nonetheless, I highly recommend this text to anyone in the U.S. who needs a tractable key to algal genera of freshwater systems.

DONNA W. VOGLER. Department of Biological Sciences. University of Pittsburgh, PA 15260
ASB Bulletin 47(4), December, 2000

Bespr.: Berichte der Bayerischen Botanischen Gesellsch., Band 71, Juli 2001 top ↑

Das Buch stellt eine Einführung zu den wichtigsten Gattungen der in den Vereinigten Staaten vorkommenden Süßwasseralgen dar. Es gliedert sich in einen knappen einführenden Teil mit Angaben zur Zielsetzung des Buches, einen relativ kurz gehaltenen aber informativen und für die Benutzung der Bestimmungsschlüssel wichtigen Teil über Definition und Taxonomie, einen Methodenteil mit kurzen Ökologiehinweisen und Erläuterungen zum Gebrauch des Schlüssels. Der Bestimmungsteil ist in neun Sektionen gegliedert. Am Schluß folgt wie gewohnt eine Liste der wichtigsten Literaturquellen und ein Index der Gattungen.

DILLARD bietet einen Einstieg für Studenten und interessierte Laien, einen ersten Kontakt zur Taxonomie der Süßwasseralgen der Vereinigten Staaten - ohne mit einer Vielzahl von Fachbegriffen überfordert zu werden. Die Grundbegriffe der Algentaxonomie müssen dem Benutzer aber durchaus geläufig sein. Die Bestimmungsschlüssel erleichtern dennoch durch ihre einfach gestaltete Art das Erkennen und Benennen der geläufigsten Algen bis zur Gattungsebene für annähernd 300 Gattungen, die überwiegend auch in Europa zu finden sind. Zunächst wird durch einen vorangehenden Schlüssel aufgrund von Form, Farbe und Gestalt die Sektion eingegrenzt, um dann innerhalb der Sektion bis zur Gattungsebene zu bestimmen. Ergänzend liefert eine Literaturliste Informationen über mögliche weiterführende Literatur für denjenigen Benutzer, der tiefer in die Materie einsteigen will. Die im Text eingefügten Zeichnungen (ausschließlich aus der älteren Algenliteratur entnommen) sind hilfreich, hätten aber durch Photographien gattungstypischer Arten einiges an Aussagekraft gewonnen und würden den für ein Buch mit Spiralbindung doch relativ hohen Preis rechtfertigen.

E. Facher
Berichte der Bayerischen Botanischen Gesellschaft, Band 71, Juli 2001

Rev.: SIL News, vol. 36, May 2002, p. 14 top ↑

Common Freshwater Algae of the United States by Gary E. Dillard takes an innovative approach to the challenging task of introducing students to the morphologically diverse world ofalgaltaxonomy. Traditionally, students and aquatic ecologists with little experience have begun this arduous endeavour by learning the myriad of morphological terms associated with taxonomy. Skill is gained through the often painful experience of identifying specimen after specimen, while working through numerous phylogenetic-based keys.

A working knowledge of even the most commonly encountered genera takes considerable time and effort. I personally have never seen an individual acquire a high level of taxonomic expertise without a mentor's guidance. The emphasis on growth forms in this key, rather than the often ambiguous phylogenetic characteristics of algae, should help the novice student gain skill and confidence quickly, even when working principally on their own. The initial familiarity with the common forms of algae acquired using this key can substantially reduce the effort needed to develop a working knowledge of the field.

The coverage of the genera commonly encountered in the Continental United States is reasonably thorough, but I personally would prefer to see a more substantive survey. The text would be more useful in my introductory courses if it included illustrations for all of the genera described in the key. I would also like to see more than one illustration for some of the more morphologically diverse genera. Also, as a phycologist working in Canada, I am disappointed that the survey stops at the Canada - United States border. The wealth of information on the algal taxa of northern habitats is particularly rich and would have made a superb addition to this key.

The exclusion of the Bacillariophyceae from such a general key is regrettable. The prevalence of diatoms in all the traditional algal habitats ensures that anyone examining natural samples will frequently encounter representatives from this group. Hence, in addition to this key, the novice phycologist will also be compelled to consult a separate taxonomic key for the diatoms. This could complicate the learning process, as the novice may arrive at the group only after the elimination of all other possibilities. Subsequent examination of specimens to identify the diatom genera will necessitate the use of a key structured instead, around phylogenetic characteristics, hence confusing the novice. This could have been avoided by including the diatoms as in the earlier introductory guide "How to Know the Freshwater Algae" by G.W. Prescott (1978).

The introduction outlining algal habitats and collection methods is somewhat biased towards the large algae. In taking this approach the author is likely attempting to simplify the learning experience, and reasonably so. However, neglecting to mention the Utermohl method for enumerating whole water samples fails to emphasize the importance of the nanno-, ultra- and picoplankton that predominate in a great many waterbodies. Indeed, many of the genera illustrated in this text would not normally be evident from net hauls. Furthermore, many large mucilaginous colonies with small individual cells, such as Merismopedia, tend not to hold together when collected by net haul, and consequently, are to varying degrees, a casualty of the collection procedure. Despite what I perceive to be the aforementioned shortcomings of this key, I strongly recommend the book and its practical approach to developing an understanding of freshwater algae. In my experience, it can be a very effective teaching aid for the laboratory component of an introductory course in phycology. It clearly should also be found on the bookshelf of all professional aquatic biologists and fledgling phycologists.

Chris Earle

SIL News, vol. 36, May 2002, p. 14

Table of Contents top ↑

Statement of Purpose 2
Algae: Definition and Classification 3
Freshwater Algal Habitats and Collection Methods 4
On the Use of Dichotomous Keys 5
Key to Sections 7
Section I: Charales, Plant-Like Genera 8
Section II: Unicellular Flagellated Genera 10
ection III: Unicellular Non-flagellated Genera 30
Section IV: Colonial Flagellated Genera 67
Section V: Colonial Non-Flagellated Genera 77
Section VI: Unbranched Filamentous Genera 110
Section VII: Branched Filamentous Genera 144
Section VIII: Pseudoparenchymatous Genera 161
Section IX: Coenocytic or Sac-Like Genera 163
Bibliography and Literature Cited 165
Index to Genera 169