Kingdom Plantae:
Gymnosperms
Gymnosperms
•
•
•
•
Phylum Cycadophyta (cycads)
Phylum Coniferophyta (conifers)
Phylum Ginkgophyta (gingko)
Phylum Gnetophyta (gnetophytes)
Phylum Cycadophyta (cycads)
• Small (about 200 species)
• Mainly tropical
– 1 U.S. species: found in Florida (Zamia pumila)
Phylum Cycadophyta (cycads)
• Sporophyte features:
– Trunk woody
– Leaves often spiny and pinnately compound
(divided into thin sections: feather-like).
Note
woody
trunk
Pinnately compound
leaf
Phylum Cycadophyta (cycads)
• Sporophyte features:
– Pollen made in pollen cones
Encephalartos pollen cones
Phylum Cycadophyta (cycads)
• Sporophyte features:
– Seeds made in seed cones
Encephalartos
female cone
Megasporophylls of Cycas Ovule-bearing leaf
(megasporophyll) of cone
Phylum Cycadophyta (cycads)
• Sporophyte features:
– Plants dioecious: separate male and female
individuals.
Cycas revoluta female
Cycas revoluta male
Phylum Cycadophyta (cycads)
• Importance:
– Some used horticulturally: Cycas revoluta (sago palm)
Phylum Cycadophyta (cycads)
• Importance:
– Some are endangered in the
wild
– Example: South Africa has
40 species, all endangered
Phylum Cycadophyta (cycads)
• Importance:
– Since 1965, must have
permit to own cycad in
South Africa
– One species extinct in wild.
All plants left are males in
gardens! Propagated by
suckers (side branches).
Encephalartos woodii, known
only from male plants
Phylum Cycadophyta (cycads)
• Importance:
– Was a dominant land plant group during dinosaur
era (Mesozoic Era).
Phylum Coniferophyta (conifers)
• Largest gymnosperm group: 600 species
• Dominates biomes in far north and south
temperate zones
• Many species with narrow leaves (needle-leaved
trees)
• Examples: Pines (Pinus), Junipers (Juniperus),
Firs (Abies), Cypresses (Taxodium)
Phylum Coniferophyta (conifers)
• Importance:
– Also dominant group during Mesozoic Era (dinosaur
time!)
Extinct Conifers
• Example, Petrified Forest National Park, Arizona
• Most trees there are extinct conifers whose trunks are
mineralized.
Phylum Coniferophyta (conifers)
• Importance:
– Conifer forest biome
(covers large part of
Earth’s landmass)
Conifer forests occupy high
mountains in North America
Temperate rain forest in
Washington/Alaska
Phylum Coniferophyta (conifers)
• Importance:
– Currently dominant in parts of North
(and South) Temperate Zones
Light green
is taiga or
boreal forest
(conifers)
Phylum Coniferophyta (conifers)
• Importance:
– Some communities in southeast dominated by conifers
– Example, cypress (Taxodium) swamps
Cypress branch
Cypress swamp near Monroeville AL
Phylum Coniferophyta (conifers)
• Importance:
– Some communities in southeast
dominated by conifers
– Example, cypress (Taxodium) swamps
BIOL 6140 (Plant Ecology) classes explore swamps on field trips
Phylum Coniferophyta (conifers)
• Importance:
– Biological records (largest
tree)
– Sequoiadendron gigantea (big
tree)
– In Sequoia National Park, CA
– Base: 102 feet circumference
– Weight: 2,145 tons
– Volume: 52,500 cubic feet.
Phylum Coniferophyta (conifers)
• Importance:
– Sequoiadendron gigantea
(big tree)
Phylum Coniferophyta (conifers)
• Importance:
– Biological records (oldest
tree)
– Bristlecone Pine (Pinus
longaeva). Found in high
mountains of deserts of
California, Nevada, Utah,
Colorado, etc.
Phylum Coniferophyta (conifers)
• Importance:
– Oldest tree was 4,950
years. Cut down in 1964
by graduate student who
got corer stuck in tree
(U.S. Forest Service gave
permission!)
– Now oldest known
bristlecone (named
Methuselah) is 4,767
years old. Location kept
secret from public!
Phylum Coniferophyta (conifers)
• Importance:
– Biological records
(tallest living tree)
– Coast redwood
(Sequoia
sempervirens)
– Grow on coast of
California/Oregon (ex,
Redwood National
Park)
– 96% have been logged
Phylum Coniferophyta (conifers)
• Importance:
– Biological records (tallest living
tree)
– Coast redwood (Sequoia
sempervirens)
– Tallest tree is 368 feet tall!.
Phylum Coniferophyta (conifers)
• Importance:
– Biological records (smallest trees?)
– Pygmy forest in Mendocino County, CA
Phylum Coniferophyta (conifers)
• Importance:
– Biological records (smallest trees?)
– Pygmy forest in Mendocino County,
CA
– Hardpan (like cement) forms at
about 1 foot depth
– Dry in summer, floods in winter.
Phylum Coniferophyta (conifers)
• Importance:
– Stress makes conifers (a pine
and a cypress species) stunted
The trees on
the right had
about 30 rings
(30 yr old!)
Phylum Coniferophyta (conifers)
• Conifers in Southern Hemisphere too
• Example, Wollemi “Pine” (Australia)
• Thought extinct, small stand found in in
1994. 40 plants!
Discoverer
David
Noble
Conifers: Economic
Importance
– Harvest for pulp and timber
– Can cause controversy, especially
when old-growth and clearcuts
involved.
Conifers: Economic Importance
– Importance in Alabama: forestry #1 legal
agricultural crop
– Many pine plantations in southeast.
Conifers: Economic Importance
– Edible (pine “nuts” are pine seeds)
– Harvested from several species, including pinyon
pine from western U.S. (shown below).
Pinyon
pine
Pine seeds
Conifers: Economic Importance
– Medicines: example, taxol
– Antitumor agent. First extracted from bark of Pacific
Yew (Taxus) tree
– Now made synthetically.
Pacific Yew, showing
needles and bark
Phylum Coniferophyta (conifers)
• Importance:
– Threatened by humans (acid rain and forest decline)
– Acid rain areas (below) include some conifer
forests.
Phylum Coniferophyta (conifers)
• Importance:
– Acid rain and others
stresses cause “forest
decline”, weakness
and death of conifer
trees
– Seen in N. Europe
and N. America.
Damage/death of fir
trees in Tennessee
Phylum Ginkgophyta (Ginkgo)
• Tiny group (1 living species: Ginkgo biloba)
• Also called maidenhair tree
Phylum Ginkgophyta (Ginkgo)
• Living fossil: Leaf fossils 150 million years old
Photo of modern and fossil Gingko leaves
Phylum Ginkgophyta (Ginkgo)
• May be oldest living species on Earth!
Dinosaurs under a Ginkgo tree in the Mesozoic fall
Phylum Ginkgophyta (Ginkgo)
• Today considered extinct in wild
• Ancient trees (to 3,000 years old!) found in
China & Japan, in temple gardens and places
tended by people.
Ancient temple tree in China
Phylum Ginkgophyta (Ginkgo)
• Leaves winter deciduous, fan-shaped, with
dichotomously-branching veins
• Made on stubby “short shoots” on branches
Short shoots with
leaf scars
Phylum Ginkgophyta (Ginkgo)
• Gingko very useful horticultural tree
• Pollution resistant, makes beautiful street tree
A very old bonsai
Ginkgo
Ginkgo in fall on Japanese street
Phylum Ginkgophyta (Gingko)
• A-bomb resistant!
• This tree in Hiroshima,
Japan, was 1.1 km from
where the first Atomic
bomb was used in 1945.
Phylum Ginkgophyta (Gingko)
• Medical uses:
• May improve
circulation, memory
• Still under study
• Pills of leaf extract
worth millions of $/yr.
Ginkgo farm (top) and drying
leaves (bottom)
Phylum Gnetophyta (gnetophytes)
• Small group (70 species)
• Only gymnosperms with vessels in xylem
(large, dead water-conducting cells)
Phylum Gnetophyta (gnetophytes)
• Three genera (2 mentioned here):
– Welwitschia from Namib desert (Africa)
– Odd, only 2 leaves!
Young plant grown in pipe
section (long taproot)
Old plant in Namib desert
Phylum Gnetophyta (gnetophytes)
• Three genera (2 mentioned here):
– Ephedra from many deserts of world
Shrub is mostly branches (ovules seen on right
Phylum Gnetophyta (gnetophytes)
• Three genera (2 mentioned here):
– This shrub was original source of drug
ephedrine
– Used as stimulant, weight loss aid, may have
side effects (stroke, etc.).
You can also find lawyers to help you
sue the makers of ephedrine pills!
You can buy
ephedrine on the
internet