In free-sporing tracheophytes, the dispersal unit is the spore (e.g.,
Dryopteris spore above), which germinates into a gametophyte-so the haploid stage is dispersed for these plants.
In the seed plants the sporophyte (embryo) is dispersed. So the
diploid stage is dispersed for seed plants as in this rice seed
above.
In this seed (Capsella sp.), note the three main parts of the embryo:
• The epicotyl will become all of the above ground parts of the plant.
• The hypocotyl will form the transition zone between the roots and the stem,
• and the radicle will form all of the below ground parts of the plant.
http://www.uwinnipeg.ca/~simmons/images/embryo3.gif
Coconut Fruit (a drupe=a fleshy indehiscent fruit with a seed enclosed
in a stony endocarp) with its single seed in the center. Peaches and
cherries are also drupes.
www.botany.hawaii.edu/faculty/webb/BOT410/Angiosperm/CoconutDrawFruitsLab.jpg&imgrefurl=http://www.botany.hawaii.edu/faculty/we
bb/BOT410/Angiosperm/FruitCoconut.htm
Tissue from the megagametophyte
Root
End
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Cotyledons
“Naked seed” e.g in this dissected Pinus sp. seed,
note young sporophyte.
http://botit.botany.wisc.edu/courses/Botany_130/Div/Phyla/
Coniferophyta/Gymnosperm/Embryo.html
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
www.pioneer-net.com/psr/wallpaper.html
Seeds
Are
Diverse
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
http://natureproducts.net/Forest_Products/Trees/Sterculia%
20brevissima%20seeds.jpg
www.prairiepoint.net/journal/images/P7200015.jpg
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
http://project.bio.iastate.edu/trees/campustree
s/AcerSaccharu/AcerSacc_fruit.html
Equisetum and
Psilotum are in
the fern clade.
(Pryer et al. 2001.
Nature 409:618-622.)
Leptosporangiate
Ferns
Ferns and Fern Allies
“True Leaved
Plants”
Seed Plants
Lycopods
Mosses
CYCADS
The basic growth
form of a cycad is
a central “trunk”
with leaves spirally
arranged at the top.
http://www.damer.com/pictures/travels/southafrica/transvaal2.jpg
helios.bto.ed.ac.uk/bto/microbes/nitrogen.htm
Cycads are dioecious
and heterosporous
Male Cone
Cycas revoluta is dioecious
Female Cone
The megasporophylls
for Cycas is leaf-like
with ovules at the
base.
The enlarged one
has been fertilized
and is developing
into a seed
Male cones are
also simple with
each
microsporophyll a
modified leaf
(forming a stalked
peltate structure).
In Zamia the megasporophyll is highly reduced to a
stalked, peltate-like structure. They are organized into a
simple cone.
Cycadaceae
Male cone and
Cataphylls (a synapomorphy) of
Cycas taitungensis
(native to Taiwan)
www.pacsoa.org.au/cycads/Cycas/taitungcone.jpg
Cycad Coralloid Roots
(a synapomorphy of cycads)
These roots grow up rather
than down and can be seen
above ground. They have
symbiotic blue-green algae
(see next slide)
www.botany.hawaii.edu/.../LabsHTML-99/ Roots/LABROT12.jpg
Coralloid roots in Cycads
Cross-section of coralloid
root showing layer of
blue-green algae
(a nitrogen fixer).
(Dioon spinulosum)
Image from Wayne’s World
Ginkgo biloba -Maidenhair
Tree
Ginkgoaceae
Note the dimorphic shoots-- short
spur shoots and the long shoots
bhort.bh.cornell.edu/conservatory/ gingko.jpg
Ginkgo Male Cone
Ginkgo ovules
Ginko sperm Multiflagellated
Anterior position of flagella
Pollination droplet on Ginkgo ovule. The droplet
is repeatedly exuded and retracted.
http://tokyocinema.net/E-ginkgo.htm
www.salisbury.edu/arboretum/
Ginkgo/GiBi/photos/GiBiSD01.JPG
Ginkgos are widely planted in urban areas because they are resistant to
pollution. They also have deciduous leaves that turn yellow before they
drop. The fruits have an outer soft layer that has a powerful sewer-like
smell.
http://images.google.com/imgres?imgurl=ana.sote.hu/Gingko.jpg
www.ucmp.berkeley.edu/seedplants/ginkgoales/ovulesnleavessm2.jpg
http://www.kikkoman.com/contents/cookbook/cook_img/G2.gif
Once the outer soft layer and the hard layer are removed,
the inner part of the Ginkgo seed can be eaten.
Pine Life Cycle - Monoecious, Heterosporous
Sporophyte,
Monoecious
simple male cone
Scales have microsporangia
on lower surface
compound
female cone
Cells in the microsporangium
undergo meiosis to form
microspores (Pollen grains)
Cone scales
have 2 ovules
on the upper
surface.
One cell(megaspore
mother cell) in the ovule
undergoes meiosis.
One meiotic product
(haploid) survives.
This is the megaspore.
Microspores germinate
into a male gametophyte
The megaspore develops
into the female
gametophyte
Pine Ovule sits on top
of a cone scale and is
a mix of sporophytic
and gametophytic
tissues
Pollen (microspore)
lands on the ovule
and germinates into
a male
gametophyte
(pollen tube and
associated cells)
which carries the
gametes to the
archegonia which
contains the egg.
Pine ovule
Evolution of the female cone in the Pinaceae
Cordaites
extinct
Lebachia
extinct
Dwarf shoots (d s) with ovules (o) and sterile
scales (ss) all subtended by a bract (br).
Pinus
The ovule flips forward
and the shoot, scales
and bract fuse to form
the cone scale.
Conifer
Families
Our focus is on 3 ( )of
the 7 conifer (cone
bearing) families
Pinaceae
Pinus
Picea
Larix
Abies
Tsuga
www.wisc.edu/botit/img/bot/130/Gymnosperms/Coniferophyta%2520Images/Pinus%2520Images/Microsporangiate/pine%2520pollen%2520MC.jpg
Male cones are
Simple.
Pinus sp.
Female cones are
complex
The winged seed and
the ovule opening
towards the cone axis are
both synapomorphies.
The wing is derived
from scale tissue.
http://www.zoobotanica.u-net.com/GIF%20files/Botanical/pine.GIF
Close up of 2 ovules
which open towards
the cone axis
(a synapomorphy)
X-section of young
female pine cone
www.science.siu.edu/landplants/Coniferophyta/images/Pinus.female.cone.Sect.JPEG
Pine pollen
(Microspore)
Note:The “wings” are
Actually air bladders
which may facilitate
wind dispersal
or the pollination
process itself.
Tube nucleus
Generative nucleus
(will divide to form
2 sperm nuclei)
www.wisc.edu/.../Microsporangiate/ pine%20pollen%20MC.jpg
Pine pollen grains viewed
with fluorescent microscopy.
You can see the bladders
(“wings”) more easily than
under conventional
microscopy.
micro.magnet.fsu.edu/.../gallery/
pinetreepollen.html
Picea glauca
White Spruce
Pinaceae
There are 35-40 species of Picea
worldwide. Half are in China
Range map in N.Am. Picea, the genus, is
circumboreal and occurs as a co-dominant with firs
(Abies spp.) in vast expanses of spruce-fir forests.
Picea rubens
Red spruce
Pinaceae
P. rubens is our Eastern
species. It has small hairs on
its branches. Its range
extends south along the tops
of the Appalachians. Locally
it occurs on top of Mt.
Greylock and the Dome.
Range Map- note eastern distribution
Picea abies
Norway Spruce
Pinaceae
An introduced European
spruce widely planted on
campus. Note large cones,
upward sweeping branches
and and droopy branchlets.
It’s profile desingates it as a
60mph species!
Abies balsamea
Balsam Fir
Pinaceae
Note: Upright cones with deciduous cone scales
leaving upright “candles” and triangular profile.
http://wiscinfo.doit.wisc.edu/herbarium/photos/ABIBAL_KKOHOUT.jpg
Range Map showing eastern
distribution. Note there are 40 species
of Abies worldwide (9 in the US).
Larix laricina
Larch
Pinaceae
Larix laricina is our only deciduous
conifer. It has dimorphic shoots-long and spur shoots.
Tsuga canadensis
Hemlock
Pinaceae
Note droopy top (a 60mph
characteristic), small hanging
cones, row of leaves parallel to
the stem axis.
Cupressaceae
Thuja
Juniperus
Juniperus communis, Common Juniper, Cupressaceae, female plant
Junipers are dioecious.
Juniperus communis
Common juniper
Cupressaceae
Cones are made up of 3
fleshy scales which give
the appearance of a
“berry”!
Leaves are awl-shaped with a single
white “stripe” of stomates in the center.
Juniperus virginiana, Eastern Red Cedar, Cupressaceae,
http://www.csdl.tamu.edu/FLORA/mi06/mi06012.jpg
Juniperus virginiana showing scale-like leaves that are 4-ranked,
developing fruits (mature fruits are blue).
Close up of branch showing leaf arrangement in 4’s-2 on each side, one in the middle, and one behind.
Range map in N.Am.
Thuja occidentalis, Northern White Cedar, Cupressaceae
Thuja occidentalis
White Cedar
Cupressaceae
Note scale-like
leaves and flattened
Branches. Leaves
also have glands
(not visible).
Thuja occidentalis
White Cedar
Cupressaceae
Old cones
Young cones
Taxaceae
Taxus
Seeds of Taxus are enclosed in a fleshy aril
(an outgrowth of the stem below).
Leaves are arranged spirally around the
stem but appear 2-ranked. Petioles and
the underside of the leaves are yellow.
Taxus canadensis
Yew
The conifers have the
Most massive =
Giant Sequoias
Sequoiadendron giganteum
(Cupressaceae)
…...
..The Tallest = Coastal
Redwood (Sequoia
sempervirens)
(Cupressaceae)
….
.. And the oldest = Bristlecone Pine
Pinus longaeva (Pinaceae).