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Pteridophyte reproduction
Embryophytes
Modified 17-13 (19-9)
Rhynia (Fossil)
Lycopodiophyta
Liverworts
Hornworts
Mosses
To be cont.
Pteridophyta
“Bryophytes”
microphylls
megaphylls
Transition
to land
Microphylls
• One vascular trace
– No branching vasculature in leaf
– Forms from protostele
http://28.media.tumblr.com/tumblr_lgpco8M9Ie1
qa2aauo1_500.jpg
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Megaphylls
– Branching vascular traces (veins) in leaves
– Typically large
http://intro.bio.umb.edu/111112/OLLM/112s99/phyla/plants/pterophyta.jpg
Are not always large.
Highly reduced megaphylls in
Equisetales.
http://www.missouriplants.com/Ferns/E
quisetum_hymenale_stems.jpg
Remember the STELES
Pteridophyta
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Stele modification in Pteridophyta
(a few with eustele)
eustele
siphonostele
ancestor had protostele,
like Lycopodiophyta.
Protosteles
Lycopodiophyta
Siphonosteles
Most ferns, though, have siphonosteles with leaf gaps
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Eusteles
Equisetales—eusteles; convergent with seed plants.
Modification of life cycle and reproduction in Pteridophyta
Heterosporous ferns
Filicales
endosporic gametophyte
heterospory
Eusporangiate ferns
Equisetales
leptosporangia
above-ground photosynthetic
gametophyte
above-ground photosynthetic
gametophyte
ancestor had dominant homosporous
sporophyte with underground
non-photosynthetic gametophyte,
like Lycopodiaceae
Life cycles: above-ground photosynthetic gametophyte
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Modification of life cycle and reproduction in Pteridophyta
2. Leptosporangia
Heterosporous ferns
Filicales
endosporic gametophyte
heterospory
Equisetales
Eusporangiate ferns
leptosporangia
above-ground photosynthetic
gametophyte
ancestor had dominant homosporous
sporophyte with underground
non-photosynthetic gametophyte,
like Lycopodiaceae
Life cycles: eusporangia vs. leptosporangia
Eusporangia:
large
1 to 1000’s of spores
the basal (primitive) condition
walls several cells thick
found in most land plants
Leptosporangia: small
64 spores
walls one cell thick
have annulus (thickened ring)
grouped into sori (sing. sorus)
only in Filicales and heterosporous ferns
Life cycles: eusporangia
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Life cycles: eusporangia in a eusporangiate fern (Botrychium)
Life cycles: leptosporangia
Life cycles: leptosporangia in Filicales
http://t0.gstatic.com/images?q=tbn:ANd9GcQ5dCnB8I61yQSkLGFZHRNK9s
zAhC4CieR19Yvgi78YQTs01RUurg
http://www.google.com/imgres?q=leptosporangia+in+filicales&hl=en&clie
nt=firefox-a&hs=HLb&sa=X&rls=org.mozilla:enUS:official&biw=748&bih=393&tbm=isch&prmd=imvns&tbnid=cDA5fNilc
4DjaM:&imgrefurl=http://www.increasemyvocabulary.com/definition/of/le
ptosporangium/&docid=ULNACsnDhf5jM&imgurl=http://farm3.static.flickr.com/2127/2263445746_6
1832fff71.jpg&w=500&h=375&ei=-2OsTtbwC62rsALHi8WADw&zoom=1
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Life cycles:
leptosporangia grouped
into sori in Filicales
(Thelypteris)
http://t2.gstatic.com/images?q=tbn:ANd9GcR67ZaOrG_IZnVCT
JlKNnzNb9xRzv2WRyzTn65QY9_qNAtdmw-d
Life cycles: leptosporangia grouped into sori
in Filicales (Asplenium)
http://t2.gstatic.com/images?q=tbn:ANd9GcRa-RawiaCHFAk1U2wWgyE4uwVRf-2z5DuiTDyJ5trjRpP7kMP
Modification of life cycle and reproduction in Pteridophyta
3. Heterospory and endosporic gametophytes
Heterosporous ferns
Filicales
endosporic gametophyte
heterospory
Equisetales
Eusporangiate ferns
leptosporangia
above-ground photosynthetic
gametophyte
ancestor had dominant homosporous
sporophyte with underground
non-photosynthetic gametophyte,
like Lycopodiaceae
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Life cycles: heterospory
The life cycle of Selaginella is the same as that found in the
heterosporous ferns and in the seed plants.
Embryophytes
Rhynia (Fossil)
Lycopodiophyta
Liverworts
Hornworts
Mosses
To be cont.
Pteridophytes
“Bryophytes”
megaphylls
Transition
to land
Equisetales: brief overview
--highly reduced megaphylls
--eusteles
--homosporous
--eusporangia
i
--above-ground photosynthetic gametophyte
--strobili
--hollow, jointed stems embedded with silica
--one genus, Equisetum, about 15 species;
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Equisetales: Equisetum
Equisetales is the only
fern group with strobili.
Strobili are stems with
modified leaves–
sporophylls—clustered
p p y
on
them. These sporophylls are
often called sporangiophores
on Equisetum.
http://www.sbs.utexas.edu/bio406d/images/pics/
equ/Equisetum%20hyemale%20strob1.jpg
Equisetum: strobili
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Embryophytes
Rhynia (Fossil)
Lycopodiophyta
Liverworts
Hornworts
Mosses
To be cont.
Pteridophytes
“Bryophytes”
megaphylls
Transition
to land
Eusporangiate ferns: brief overview
--megaphylls
--protosteles
--homosporous
homosporous
--eusporangia
--underground, non-photosynthetic gametophyte
--includes Psilotales and Ophioglossales
--7 genera, about 70 species
Eusporangiate ferns: Ophioglossales: Botrychium
What you’re seeing here is one leaf
http://www.rook.org/earl/bwca/nature/ferns/botrychiummultifidum-1sm.jpg
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Eusporangiate ferns: Ophioglossales: Ophioglossum
http://hengduan.huh.harvard.e
du/fieldnotes/photos/show_ima
ge?image_id=1140
Eusporangiate ferns: Psilotales: Psilotum
http://t0.gstatic.com/images?q=tbn:ANd9GcRN0J
vXD52gT892P9oJD7fNeMmehdMwcUyqLf8yF_A
TVFbdvvh0
Embryophytes
Rhynia (Fossil)
Lycopodiophyta
Liverworts
Hornworts
Mosses
To be cont.
Pteridophytes
“Bryophytes”
megaphylls
Transition
to land
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Heterosporous ferns: brief overview
--all aquatic
--megaphylls
--siphonosteles
--heterosporous
p
--leptosporangia
--endosporic gametophyte
--includes Marsileales and Salviniales
--5 genera, about 70 species
Heterosporous ferns: Salviniales: Azolla
http://nas.er.usgs.gov/XIMAGESERVERX/2007/20071004180006.jpg
Heterosporous ferns:
Salviniales: Salvinia
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Heterosporous ferns:
Marsileales: Marsilea
Embryophytes
Rhynia (Fossil)
Lycopodiophyta
Liverworts
Hornworts
Mosses
To be cont.
Pteridophytes
“Bryophytes”
megaphylls
Transition
to land
Filicales: brief overview
--megaphylls
--siphonosteles (mostly) – few with eusteles
--homosporous
homosporous
--leptosporangia
--above-ground, photosynthetic gametophyte
--about 320 genera, 10,500 species
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Filicales: Dennstaedtia
Filicales: Pteridium
http://t2.gstatic.com/images?q=tbn:ANd9GcQSnzinzDmcXng7WDPh3KaypqI3JJUDSxUWSbyCjSa91eTqQOzcg
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