Gelidiales

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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
4923-33) 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?
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Apical Cell
single apical cell
Gelidiales will have a single apical cell
Gelidiopsis, Wurdemannia will have multiple
apical cells
multiple apical cells
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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
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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 YES Parviphycus
2nd order branch cells
2nd order branch cells
central axial cells
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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 youll be
famous
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Rhizoids-holdfasts
Refined and expanded by Perrone et al. (2006)
Botanica Marina 4923-33.
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Rhizoids-holdfasts
Gelidiella Parviphycus (Gelidiellaceae) Indepen
dent 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) Com
plex 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
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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
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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