Key to the
BROWN ALGAE
of Long Key,
Florida
Duane
Kauffmann, Ph. D.
With Appreciation to
Jonathan Roth. Ph. D.
C. Franklin Bishop, Ph. D.
Anthony Swinehart, Ph. D.
ABOUT THE
GUIDE
This guide covers
identification of the brown algae which have been found near Long Key, Florida. Similar guides are also available
for the green and red algae.
The various pages of this
guide make reference to resource materials that may be consulted for additional
identification information. The
sources, cited in the guide by author name, include:
Dawes, Clinton & Mathieson,
Arthur. (2008). The
Seaweeds of Florida.
Gainesville, FL: University
Press of Florida.
Littler, Diane & Littler, Mark. (2000). Caribbean Reef Plants.
Washington, DC: Offshore Graphics, Inc.
Taylor, William. (1960). Marine Algae of the Eastern Tropical and
Subtropical Coasts of the Americas.
Ann Arbor, MI: University
of Michigan Press.
Note: The process of identification will usually be successful when one has a good quality, mature specimen with which to work. Unfortunately one sometimes collects only a portion of an alga and/or one which is sun-bleached or otherwise damaged. Working with such specimens can often prove quite frustrating and a decision must be made about how much time and energy to put into the identification of such algae.
ABOUT THE AUTHOR
Trained in the field of social psychology, Dr. Duane Kauffmann (Ph. D., University of Illinois) taught psychology at Goshen College for 40 years. His life-long interest in ocean life and friendships (and golf outings) with Dr. Roth and Dr. Bishop led to a second career in Marine Biology. Dr. Kauffmann has more than 30 years experience in the marine environment around Long Key.
Dr. Kauffmann wishes to give special recognition for
the ideas and stimulation provided by:
Dr. Jonathan Roth, founder of the Goshen College
Marine Biology program to whom I owe appreciation for getting me hooked on
marine biology and with whom I discussed algae identification on many
occasions.
Dr. Frank Bishop, who made the appreciation of algae
so infectious one wished to know the scientific name and who formulated a
text-only dichotomous algae key which was used for many years by Goshen College
Marine Biology students.
Dr. Tony Swinehart, Goshen College graduate and now
Associate Professor of Biology at Hillsdale College, who has been a great
friend and colleague in studying marine life near Long Key, FL.
Choose one of the following
options. To go to index, click here.
1a. Plant has bladders or
floats......................................................................Go to page
10
Float from Sargassum
1b. Plant of rounded
leaves............................................................................Go to page
40
Padina sanctae-crucis
1c. Plant of flat, narrow,
branches..................................................................Go to page
80
Dictyota cervicornis
Page 10
Choose
one of the following options.
10a. Plant with pyramidal blades with
internal floats.....................................Turbinaria
10b. Plant with very small blades, round
floats…………………… . ……….Cystoseira
10c. Plant with blades, round
floats……………………………………...…..Sargassum
Page 12
Turbinara turbinata
Turbinara
turbinata
is a tall brown plant reaching 40 to 45 cm in height. It is characterized by pyramid-shaped blades which are flat
or slightly convex on top. Blades
to slightly over 1 cm in width at top.
Air bladder embedded in blade.
(See Dawes & Mathieson, p. 164;
Taylor, p. 285; Littler & Littler, p. 290)
Top portion of Turbinara turbinata
Blades of Turbinara turbinata
Page 15
Cystoseira
myrica
Cystoseira myrica is wiry in character, to 30 cm in height, and tan to brown in color. Blades are short, cylindrical, blunt projections. Floats are found on the outer portions of the branches and have several short projections on surface. (See Dawes & Mathieson, p. 157; Taylor, p. 267; Littler & Littler, p. 280)
Page 18
Sargassum
Sargassum is a genus comprising two
distinct types. While all Sargassum has rounded floats, some
species are found attached to the substrate, while others are found as floating
clumps or masses.
18a. Plant attached to substrate, brown to
dark brown..........Sargassum pteropleuron
18b. Plant attached to substrate, spine on floats……………....Sargassum filipendula
18c. Plant floating in clumps, floats with
no spines at apex............Sargassum fluitans
18d. Plant floating in clumps, floats have
spines at tip.....................Sargassum natans
Go to page 26
Page 20
Sargassum
pteropleuron
Sargassum
pteropleuron grows attached to the substrate and may reach heights of several
meters. Blades long (to 8 cm),
narrow (to 7 mm), with a prominent midrib giving the blade a triangular
cross-section. Blade midrib with
numerous teeth, especially at base.
Floats large, smooth, and located along main axis. (See Dawes &
Mathieson, p. 162; Taylor, p. 274; Littler & Littler, p. 286)
Top portion of plant of Sargassum pteropleuron
Air bladders
Page 22
Sargassum filipendula grows attached to the substrate and may reach one
meter in height. Plant is sparsely
branched. Blades with short stipe
(1 mm), long (to 10 cm), narrow (to 8 mm), with a prominent midrib. Blade margins with numerous teeth. Floats large, smooth, and with a single
spine. Fertile branches “bumpy”;
cryptostomata appear as dark dots in leaves and on floats and stalks. (See Dawes & Mathieson, p. 159; Taylor, p. 270;
Littler & Littler, p. 282)
Fertile branchlets
Cryptostomata in leaf
Spine on float
Page 24
Sargassum
fluitans
Sargassum
fluitans is found floating in small
to medium clumps to large masses.
Blades flat (to 8 mm wide, 6 cm long) with a prominent midrib. Blade margins with numerous teeth. Floats smooth and located along main
axis, numerous, often 1 or 2 at base of each blade. (See Dawes & Mathieson, p. 160; Taylor, p.
281; Littler & Littler, p. 282)
Top of Sargassum fluitans
(Note: Small white lines seen projecting from
leaves are hydroids, they are not part of the alga. It is not unusual, indeed, it is very common, for Sargassum to serve as substrate for
other organisms. This should be
considered when making identification.)
Page 26
Sargassum
natans
Sargassum
natans
is found floating in small to medium clumps to large masses. Blades long (to 10
cm) and narrow (to 4 mm). Blade
margins with numerous teeth.
Floats with a spine or leaf-like projection at apex and located on
elongated stems connected to main axis. (See Dawes & Mathieson, p. 161; Taylor, p.
281; Littler & Littler, p. 284)
Page 40
Padina
Padina is a genus of brown algae
characterized by fan-shaped blades.
Color is brown, but often covered with a light crust of lime giving a
white appearance to the plant.
40a. Plant of fan-shaped blades, two cells
thick throughout…..Padina
sanctae-crucis
40b.
Plant of fan-shaped blades, 6 to 9 cells thick at base……......Padina gymnospora
Page 42
Padina sanctae-crucis is a plant of fan-shaped or cup-shaped blades. Upper surface often chalky white. Blades concentrically zoned. Apex of blades in-rolled. Blades two cells thick throughout. Inner cells small, rectangular, to 35
microns wide; outer cells to 60 microns wide. (See Dawes & Mathieson, p. 129; Taylor, p.
237; Littler & Littler, p. 276)
Close-up showing cross-section two cells thick
Page 44
Padina gymnospora is a yellow-brown plant of fan-shaped to cup-shaped blades. Little or no calcification. Apex of blades in-rolled. Blades 2-3 cells thick at margins, 6 to
9 cells thick below. (See
Dawes & Mathieson, p. 128; Taylor, p. 237; Littler & Littler, p. 276. Taylor has P. vickersiae and P.
gymnospora as separate species, Dawes & Mathieson and Littler &
Littler have them as the same.)
Page 80
Dictyota
Dictyota is a genus of brown algae
with flat branches of various dimensions.
Branches no more than two cells thick.
80a. Plant with very narrow branches (1.5 mm
or less) throughout...Dictyota caribaea
Go to page 82
80b. Plant with branches to 2.5 mm
wide…………………..……Dictyota cervicornis
Page 82
Dictyota
caribaea
occurs in bushy, tangled, clumps to 12+ cm tall. Yellowish to tan to olive-brown. Branches less than 1.5 mm throughout, often twisted. Branching generally dichotomous, apices
pointed. (See Dawes &
Mathieson, p. 121; Taylor, p. 219 D.
linearis; Littler & Littler, p. 260)
Habit of Dictyota caribaea
Page 84
Dictyota cervicornis occurs in bushy clumps to 20
cm tall. Yellowish to tan to
olive-brown. Branches to 2.5 mm,
often twisted. Branching generally
dichotomous, apices bluntly rounded.
(See Dawes & Mathieson, p. 121; Taylor, p. 218 D. dichotoma, p. 222 D. cervicornis; Littler & Littler,
p. 260. Littler and Littler do not
list D. dichotoma. Taylor has D. cervicornis and D.
dichotoma as separate species.)
Habit of Dictyota cervicornis