Kingdom Plantae:

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).

Phylum Cycadophyta (cycads)

*    Sporophyte features:

  Pollen made in pollen cones

 

Phylum Cycadophyta (cycads)

*    Sporophyte features:

  Seeds made in seed cones

Phylum Cycadophyta (cycads)

*    Sporophyte features:

  Plants dioecious: separate male and female individuals.

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).

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)

Phylum Coniferophyta (conifers)

*    Importance:

  Currently dominant in parts of North (and South) Temperate Zones

Phylum Coniferophyta (conifers)

*    Importance:

  Some communities in southeast dominated by conifers

  Example, cypress (Taxodium) swamps

Phylum Coniferophyta (conifers)

*    Importance:

  Some communities in southeast dominated by conifers

  Example, cypress (Taxodium) swamps

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

Phylum Coniferophyta (conifers)

*    Conifers in Southern Hemisphere too

*    Example, Wollemi "Pine" (Australia)

*    Thought extinct, small stand found in in 1994. 40 plants!

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).

 

 

Conifers: Economic Importance

  Medicines: example, taxol

  Antitumor agent. First extracted from bark of Pacific Yew (Taxus) tree

  Now made synthetically.

 

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.

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

 

 

Phylum Ginkgophyta (Ginkgo)

*    May be oldest living species on Earth!

 

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.

Phylum Ginkgophyta (Ginkgo)

*    Leaves winter deciduous, fan-shaped, with dichotomously-branching veins

*    Made on stubby "short shoots" on branches

 

Phylum Ginkgophyta (Ginkgo)

*    Gingko very useful horticultural tree

*    Pollution resistant, makes beautiful street tree

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.

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!

Phylum Gnetophyta (gnetophytes)

*    Three genera (2 mentioned here):

  Ephedra from many deserts of world

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.).