In 1989, Gary Dillard published the first book in his series of
floristic treatments on selected groups of freshwater algae from the
southeastern United States. This is the eighth, and probably the last,
in the series and focuses on the chl c–containing microalgal classes,
exclusive of the diatoms. Various freshwater green-algal groups are
covered in parts 1–6, and the pigmented Euglenophyceae comprise part
7. As with the previous books, only the pigmented forms are included
in part 8. Dillard explains that although volumes on the Cyanophyceae
and Rhodophyceae were planned originally, they will not be
forthcoming. The region covered encompasses those states from Virginia
south to Florida and westward to the Mississippi River, including all
of Louisiana. Keys, figures, and descriptions are provided for almost
all taxa. Supportive literature citations are included for each genus,
and distributional data by state for each species. An effort was made
to update taxon synonymies. Most species are illustrated with line
drawings made from well-known publications as sources of authoritative
images. The book begins with the introduction and reiteration of
purpose as well as a key to the algal classes, followed by taxonomic
sections on the Chrysophyceae (subclasses Acontochrysophycidae,
Heterochrysophycidae, Isochrysophycidae), Xanthophyceae,
Raphidophyceae, Cryptophyceae, and Dinophyceae (subclass
Dinophycidae). The book ends with an addendum, a bibliography and
literature cited section, and an index. Plates of line drawings with
the corresponding species names on the facing pages complete the
volume. The main text occupies about 100 pages, and the bibliography
16 pages. There are 22 plates.
At first glance, this book appears to be an effort to update the algal
flora for this region in the style of Prescott (1962) and Whitford and
Schumacher (1984). Although the work does perform many of the same
functions as these classic floras, it is clear that there is a
different objective here. Dillard’s intention is not to revise the
algal flora of the southeastern United States, but to initiate a
biodiversity database on the occurrence and distribution of the
freshwater algae in the region. The goal was to document the published
flora for the region, not publish firsthand observations. He has
succeeded wonderfully, and the index should be used as a starting
point or checklist for the freshwater algal flora from the
southeastern U.S. Dillard cautions, however, that many of the species
reports utilized were ‘‘floristic lists’’ lacking documentary figures
or descriptions and, therefore, were impossible to confirm.
Although the additional effort probably was prohibitive, the author’s
goal of initiating a floristic biodiversity database would have been
enhanced if he had described the physiographic provinces comprising
the region and referred to them in the distributional reports, rather
than reporting taxa only by state. Comments on habitats also would
have been helpful. Additionally, floristic or taxonomic studies of
many of these groups frequently contain both pigmented and unpigmented
taxa, and some pigmented taxa (e.g., Dinobryon spp.) now are known to
be among the most significant bacteriovores in the plankton. Thus, the
omission of unpigmented genera from some groups appeared wanting
(e.g., several genera of scaled and naked chrysophytes, cryptomonads,
and dinoflagellates). However, the book truly pulls together a large
body of published species-level accounts on the southeastern U.S.
with keys, illustrations, descriptions, and distributional information
in a very useful, informative framework.
A series of keys has been provided to every taxon covered in the book,
including the major algal classes, orders or families, genera, and
species. The only exception is that no keys to species are provided
for the silica-scale-bearing chrysophytes, for which only a key to the
genera is given (see below). I cannot say with certainty that these
keys work well as I have not had the opportunity to use them. However,
they appear to be well written, clearly organized, and succinct. There
seems to be a strong effort to avoid ambiguous couplets. In places
where there probably are unresolved issues in distinguishing taxa
(e.g., overlapping size ranges in Cryptomonas and Tribonema species),
the couplets clearly reflect the problem and do not try to gloss over
them, effectively providing hints for further study. The
dinoflagellate keys may be particularly useful. Even though there are
a relatively large number of species in some genera, the author avoids
a long, cumbersome key in favor of several smaller keys to sections or
subgenera (e.g., Peridinium, Peridiniopsis) and then another key to
the species therein. The keys never exceed a single page, only rarely
exceed a half-dozen couplets, and instruct the user in the taxonomic
concepts utilized. They are a strength of the book.
The book’s organization makes it easy to use. The taxonomic structure
in combination with appropriate spacing, indentations, and so forth
facilitate the user in quickly finding information in both the text
and the index. The order of the plates reflects the order of coverage
in the text. Each species explanation provides the plate and figure
numbers of the taxon, while each plate’s facing page lists the page
number for each species. Likewise, the font style and size are easy to
read, even in the index and bibliography. I do have one complaint,
however. A genus name was centered at the bottom of a page with the
description following at the top of the next page an unexpectedly high
number of times. It looked strange and felt cumbersome. The line
drawings are excellent and are arranged in a pleasant visual
presentation on plates occupying a full page. Mostly, the figures
seemed to be of an appropriate size—not too large, so there were only
a few per page, yet not so small as to make them difficult to
see. Closely related taxa are arranged on the same plate to rapidly
convey the range of morphological diversity and facilitate
understanding of generic or species concepts. For example, three
loricate, chrysophyte genera, Pseudokephyrion, Epipyxis, and
Dinobryon, are represented by two, five, and four species,
respectively, on plate 5; and all nine Ophiocytium species are on
plate 13. Credit is given to the author as the source of a drawing,
but not the year of the citation, making it difficult to find the
original drawing. A few figures contained multiple images, perhaps
leading to confusion if the reader is unfamiliar with the
taxa. Specifically, figure legends only contained the taxon’s name and
page number, and only a figure number was associated with each
figure. When multiple images occurred with a figure number, the
identity of a given image was unclear at times, even after reading the
corresponding text (e.g., Bourrellia skujae, plate 1, fig. 3).
However, lines linking different cell views for the same taxon were
used when needed in the dinoflagellate figures, resolving this problem
for this group (e.g., plate 18, figs. 9–11).
The author provides a brief overview of the rapidly evolving
classification scheme for the Chrysophyceae but utilizes the
‘‘traditional’’ (Dillard’s term) system of Bourrelly (1981) in this
presentation. About 25 pages plus six plates are dedicated to
freshwater chrysophycean taxa. Many nonspecialists have a poor
understanding of chrysophycean taxa because much of the taxonomic
literature is not in English or many taxa are encountered only
infrequently. The section on the Chrysophyceae will help these
folks. Users of this book will find the commonly encountered taxa
(e.g., Dinobryon, Uroglena, Ochromonas) well represented here. Many of
the poorly understood taxa are clearly delineated, including the
rhizopodial and loricate forms, unicellular flagellates, and those
with cells in gelatinous envelopes. Additionally, because electron
microscopy (EM) is required for species-level identification of the
silica-scaled species, routine examination of species is inhibited,
and taxonomic enigmas sometimes exist for species described before the
availability of EM. All pigmented, silica-scaled species in the
Chrysophyceae, including those often placed in the Synurophyceae in
other classifications, are organized as a single family
(Mallomonadaceae) following Bourrelly’s classification and occupy an
additional 15 pages. Reports that did not use EM are considered
suspect and are identified as such. Likewise, genera of questionable
validity (e.g., Microglena, Chlorodesmus) are discussed briefly. For
the silica-scaled chrysophytes, the author only provides keys to
genera, explaining ‘‘reliable keys … of all known species are
wanting’’ (p. 31) and lists the silica-scaled species
alphabetically. This presents a rather daunting list for the 84
Mallomonas species and even the 19 Synura species reported from the
southeastern U.S. However, the book by Kristiansen and Preisig (2007)
published in the same year has answered this complaint for those taxa
with bilaterally symmetrical scales (i.e., Synurophyceae). Line
drawings of a few silica-scaled chrysophyte taxa are included in the
text, the only place where this occurs in the book, while line
drawings of only three enigmatic or infrequently encountered species
are illustrated in the plates. The paucity of illustrations for the
silica-scaled chrysophytes is understandable due to the necessity of
EM for most species-level identifications. Those wishing to understand
the silica-scaled chrysophytes in the southeastern U.S. will need to
supplement this book with references like Kristiansen and Preisig
(2007) or similar publications. The haptophyte taxa are located within
the Chrysophyceae and are represented by two genera totaling three
species.
The yellow-green algae, including the Eustigmatophyceae, are organized
into the Xanthophyceae following Bourrelly (1981). They occupy 26
pages and nine plates. There is a brief discussion of several more
recent classifications. Genera in the Eustigmatophyceae are indicated
as such adjacent to the genus name. Again, the full range of
morphologies in the group is presented, including loricate, amoeboid
cells; and coccoid, filamentous, and coenocytic forms. Eighty-six
species are recorded among 41 genera; 30 of the genera are represented
by only one species. Characiopsis, Ophiocytium, Vaucheria, and
Tribonema were reported with 12, nine, nine, and six species,
respectively.
The final three classes typically are present as flagellated cells in
the vegetative state. The raphidiophytes are represented by four
species within three genera. Likewise, three cryptomonad genera with a
total of 16 species are recorded. The dinoflagellate organization
follows Popovsky and Pfiester (1990). Four nonmotile genera are
listed, each with a single species. Eleven more motile genera are
presented with Peridinium, Peridiniopsis, Gymnodinium, Ceratium, and
Woloszynskia recording nine, eight, seven, four, and four species,
respectively. In both Peridinium and Peridiniopsis, the species are
organized into sections.
This book will be a useful addition to anyone interested in
species-level identification for the algal groups contained therein or
interested in the biogeography of the southeastern U.S. The
distribution record for the groups covered in this book is poorly
known, and what is known mostly is scattered throughout the published
literature. Pulling these species reports together in one place is in
itself a significant contribution. Given the high biological diversity
in parts of the region (e.g., Great Smokey Mountain National Park) and
resurgent interest in microbial biodiversity, the appearance of this
work is timely. Finally, I particularly liked the size (23 · 14 cm)
and facile organization of the book. It will be handy to pull off the
shelf and use next to the microscope or to digest for a better
understanding of the generic or species concepts.
James L. Wee, Department of Biological Sciences, Loyola University New
Orleans, Louisiana, USA
Journal of Phycology 44 (2008), p. 1360-1362