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