Gelidiales
-Some conspicuous species are important agarophytes.
-Many(?) species inconspicuous and part of algal turfs.
-Carpogonia are intercalary, which is an exception to the
rule of red algal reproductive cells being terminal.
What to look for…
-Is there a single apical cell?
(will separate small gelids from other wirey turfs like Gelidiopsis and Wurdmania)
-Size of thallus?
-What does it look like in transverse section?
Are there rhizines? (cells with thick walls & tiny lumens)
What is x.s. shape? (terete, compressed, flattened)
Is the arrangement of medulary cells distinct near apical tips?
-What do cystocarps look like?
Bilocular or unilocular?
How are nutritive filaments, gonimoblast, carpospores arranged?
-What do tetrasporangial branches look like?
Is there a sterile margin?
How are tetrasporangia arranged (number per segment, pattern)?
-How are rhizoidal holdfast arranged? (Perrone et al. 2006. Botanica Marina 49:23-33)
Are they scattered, clumped as brushes or cylindrical or tapered pegs?
-What does branching look like?
Are branch bases constricted, tapered, or not?
Are reproductive branchlets clustered in lower parts of thallus?
Is there a bilateral series of small branchlets along the main axis?
Apical Cell
single apical cell
Gelidiales will have a
single apical cell
Gelidiopsis, Wurdemannia
will have multiple apical
cells
multiple apical cells
Transverse
Section
Characters
Are there rhizines?
NO
Gelidiella
Parviphycus
no rhizines
rhizine pattern may not be consistent
rhizines concentrated
in central medulla
rhizines scattered in
medulla
YES
Gelidium
Pterocladiella
Transverse
Section
Characters
What is shape?
compressed
terete
sub-terete
flattened
Is medullary cell arrangement distinct near apical tips?
central axial cell
3rd order branch cell
NO
Gelidiella
2nd order branch cells
YES
Parviphycus
central axial cells
2nd order branch cells
Cystocarps
characters
Gelidium
Bilocular cystocarp
Central bisecting placental tissue
Two ostioles
Carpogonia develop on both sides of blade
Nutritive filaments develop around 2nd order branch cells
Pterocladiella
Unilocular cystocarp
Placental tissue surrounds central axis
One ostiole (usually)
Carpogonia develop only as part of cell filaments
immediately adjacent to the central axis
Nutritive filaments develop around central axis
Pterocladia
Unilocular cystocarp
Placental tissue on floor of cystocarp cavity
One ostiole
Carpogonia develop on one sides of blade
If you see anything like this you’ll be famous
Rhizoids-holdfasts
Holdfast Type as a Generic Character
Perrone 1994
Shimada et al. 1999
"Independent"
Gelidiella
"Brush-T ype"
Gelidium
Pterocladia &
Pterocladiella
"Peg-T ype"
Refined and expanded by Perrone et al. (2006) Botanica Marina 49:23-33.
Rhizoids-holdfasts
Gelidiella & Parviphycus (Gelidiellaceae)
Independent unicellular rhizoidal filaments originating
from surface cortical and that remain in open connection
with their mother cells
“independent”
Gelidium & Ptilophora? (Gelidiaceae)
Complex brush-like haptera consisting of both internal
rhizoidal filaments growing independently and between
surface cortical cells, and pigmented multicellular
uniseriate filaments originating from surface cortical cells.
Rhizoidal filaments independently attaching to or
penetrating the substrate
“peg”
Pterocladia & Pterocladiella (Pterocladiaceae)
Complex peg-like haptera consisting of both internal
rhizoidal filaments coalescing in a thick sheath and
protruding between surface cortical cells, and pigmented
multicellular uniseriate filaments originating from surface
cortical cells around the hapteron base and forming a
basal cortication. Coalesced rhizoidal filaments attaching
to or penetrating the substrate
“tapered”
Tetrasporangial
branch
characters
Is there a sterile margin?
sterile margin
How are tetrasporangia arranged?
no sterile margin
chevrons
specific or
non-specific
number per
segment
Less organized
Some Caribbean Species
Gelidium microdonticum
Small turfy species with flattened
blades that have serrated margins.
Pterocladiella bartlettii
Small slender species often with a
bi-lateral series of small branchlets
along the main branch.
Gelidium floridanum
Small to medium species with
reproductive branches often
clustered towards the base of
thallus; apex of main axes
sometimes elongated, and
tetrasporangial branchlets with a
wide sterile margin.
Pterocladiella caerulescens
(including P. beachiae)
Small flattened species constricted
branch bases, monoecious