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PhycoKey History and Preface


Acknowledging Student Developers

Development and publication of PhycoKey is student-based and without grant funding.  I acknowledge the University of New Hampshire for enabling me to develop this project.  Enthusiastic students who worked on PhycoKey as ‘special investigations’ include:

John Clifford Baker (2007)

Amanda Lee Murby (2007)

Lauren Wyatt (2007)

Wendy Ryan Beagen (2007, 2008)

Carol Stockwell Elliott (2008, 2009)

Françoise Morison (2008, 2009)

Lauren Chase (2010)

Jennifer Skoolicas (2010)

Ryan Baldwin (2011)

Ryan Bonafede (2012, 2013)



PhycoKey is dedicated to George J. Schumacher (1924 - 2016) who introduced me to the fascination of aquatic microbes, especially freshwater algae, in the early 1960s at the State University of New York (SUNY) Binghamton, and to Alan J. Brook (1923 - 2013), whose primary interest was desmids, and who advised me academically the University of Minnesota, with field research at the Lake Itasca Forestry and Biological Station at the headwaters of the Mississippi River in northwestern Minnesota USA (renamed 'Itasca Biological Station and Laboratories').

Further dedication is to Peter Siver, my first graduate student and recognized for his expertise especially with Synurophyceae, who honored me by naming a newly discovered Mallomonas bakeri in 2018.


PhycoKey continuously changes as time allows, and currently includes genera of both photosynthetic (algae) and some non-photosynthetic protists, and takes excursions into other groups of aquatic organisms, trying not to overlap with other groups included elegantly in the Center for Freshwater Biology web site.

Because taxonomy is open ended, ever changing through time, the arrangement of genera in PhycoKey is contemporary with the late 20th century - a time of lively flux and revision of names, usually splitting genera and creating new generic names on the basis of molecular information such as nucleic acid base sequences.  Books and keys written today will fall out of use soon without vigorous maintenance.

In the 'anomolies' section (see cover page of the key) one can find all manner of objects found in typical water samples viewed through a student microscope, as well as aquatic vascular plants common in the littoral zone of northeastern USA.  How many times has a student pondered a bubble, a hair, a strand of plastic, a scratch on a glass slide?  I did – many times!

Overall design of PhycoKey is by John C. Baker.  Font and other details were chosen collectively by Amanda Murby, Francoise Morrison, Carol Elliott, Wendy Beagan and Lauren Wyatt at the University of New Hampshire, Durham NH USA in 2007.

In contrast to classic dichotomous text keys, PhycoKey ('algal key') is a ‘polytomous’ key with an indefinite number of choices at each logical juncture.  It has image-based comparisons with a minimum language requirement or knowledge of morphological terms, for initial identification and classification of class, order, family and genus. Species names are included where known.  Emerging publications are referenced as time allows.

Several images are presented for comparison on the same page.    As critical as are descriptive morphological terms, they tend to discourage young students.  Terminology is introduced along with images.  To a large extent it is language-independent and to date has been used by students with 209 languages in 214 countries, viewing more than 1.4 million pages. Importance of various groups of protists to users as indicated by visits places Cyanobacteria, Chlorophyceae, Euglenophyceae and Chrysophyceae in the top five positions - see graph.

PhycoKey (Phycos (Gr.) = alga), placed online in 2010, is an open-ended project continuously developing and diversifying as more marine and freshwater examples are encountered.  The emphasis is on cyanobacteria and both pigmented and colorless protista of various habitats (planktonic, benthic, subaerial, soil) as well as amoebae, flagellates, and ciliates.  Aquatic vascular plants common in North America are also included.

Raving about botanical taxonomy

What’s in a name?  Protists are separated from plants (phyto-) in the modern use of Kingdom Protista and Kingdom Plantae, and the 'algae' (phyco-) have been grouped with plants historically and currently by phytologists (botanists) and even phycologists (subsection of protistologists).  Part of the confusion is use of the term ‘Viridaeplantae’ that links plants with their predecessors the ‘green algae’ (Chlorophyceae and Charophyceae).  ‘Plant’ is defined at some level as ‘autotroph’ regardless of phylogenetic identity – inclusive of four of the six kingdoms currently recognized.

Similarly since the 19th Century we have recognized that bacteria -- photosynthetic, chemosynthetic or heterotrophic are prokaryotes (not eukaryotes), from the publications of Ernst Haeckel (1866, 1904), Edwin Copeland (1927), Edouard Chatton (1937), Herbert Copeland (1938), Stanier and van Niel (1941, 1962) and many others.  Jan Sapp (2005) published an excellent review both of early recognition of the prokaryotes, and more recently of Carl Woese  and George Fox (1977).  Incredibly cyanobacteria were classified as plants (Cyanophytes) even after ~1970 when Roger Stanier, at a A.A.A.S. meeting in Chicago, pronounced them part of the bacterial code of nomenclature.  Still today many authors cling to the old classification, retaining the extinct ‘Cyanophyta’ and Cyanophyceae’(e.g. Silva 1980) in their texts, even if parenthetically.  It’s a lesson in itself about human behavior!


Professor Arthur Mathieson, University of New Hampshire, is responsible for much of the information on marine seaweeds -- the browns, greens, and reds.  He kindly brought up to date the taxonomic nomenclature in correspondence with current usage and molecular information.  His principal interests are the global distribution of seaweeds and their ecological adaptations to diverse habitats.  His book ‘Seaweeds of Florida’, co-authored by Professor Clinton J. Dawes, University of Florida (2008) is a valuable resource.

Present and future development

Two distinct advantages of open-ended online publishing over books are 1) the opportunity to change with the times; and 2) the global distribution of the internet. 

The goals are therefore 1) to revise PhycoKey classification when molecular information redefines relationships; and 2) to reach the most isolated students anywhere.

The intended audience of PhycoKey is the student of aquatic microorganisms. Most original images of phytoplankton are photographed at a magnification of 400x with basic bright field illumination and a standard student microscope (Olympus) fitted with an Olympus digital camera (4 to 10 megapixels), then enhanced with Adobe PhotoShop.   Several images have been modified from other sites, with or without explicit permission and always with citation, to augment our own collection.

Acknowledging Global Photomicrographers

Acknowledging the photomicrography of many scientists and artists around the world, many thanks for your skills and generosity for allowing reproduction of your special photographs in PhycoKey as a service to students everywhere.

Several images were produced by Jon Dufresne, graduate student at the University of New Hampshsire.



Brook, A.J., and D.B. Williamson  2010.  A monograph on some British desmids. Price, J. H. & Evans, N. J. [Eds.]. The Ray Society. (364 pp.)

Chatton, E.  1938.  Titre et travaux scientifique (1906–1937) de Edouard Chatton.  Sett, Sottano, Italy.

Copeland, E.  1927.  What is a plant? Science 65:388–390.

Copeland, H.  1938.  The classification of lower organisms, Pacific Books, Palo Alto, Ca.

Dawes, C.J. and A.C. Mathieson  2008.  The Seaweeds of Florida.  University of Florida Press (592 pp.).

Haeckel, E.  1866.  Generelle morphologie der Organismen. George Reimer, Berlin, Germany

Haeckel, E.  1904 The wonders of life: a popular study of biological philosophy, translated by Joseph McCabe. Harper and Brothers, New York, N.Y.

John, D.M., B.A. Whitton, and A.J. Brook 2011. The freshwater algal flora of the British Isles (2nd ed.) Cambridge University Press (878 pp).

Sapp, J.  2005.  The prokaryote-eukaryote dichotomy:  Meanings and Mythology.  Microbiology and Molecular Biology Reviews 69(2):292-305.

Silva, P.C.  1980.  Names of classes and genera of living algae.  Balm, Schellema & Holkema, Utrecht dr. W. junk b.v., Publishers, The Hague.

Siver, P.A. 2118. Mallomonas skogstadii sp. nov. and M. bakeri sp. nov.: Two New Fossil Species from the Middle Eocene Representing Extinct Members of the Section Heterospinae?, Cryptogamie, Algologie 39(4):511-524.  https://doi.org/10.7872/crya/v39.iss4.2018.511

Stanier, R. and C.B. van Niel  1941.  The main outlines of bacterial classification. J. Bacteriol. 42:437–466.

Stanier, R. and C.B. van Niel  1962.  B. van Niel. 1962.  The concept of a bacterium. Arch. Mikrobiol. 42:17–35.

Whitford, L.A. and G.J. Schumacher  1969.  A manual of the fresh-water algae in North Carolina. The North Carolina Agricultural Experiment Station, Raleigh NC.

Whitford, L.A. and G.J. Schumacher  1973.  A manual of fresh-water algae. Sparks Press, Raleigh NC (324 pp).

Woese, C.  and G.E. Fox  1977.  The concept of cellular evolution.  J. Mol. Evol. 10:1-6.



Updated 30 Octmber 2020

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