WPS 224 Sub-classes of Gymnospermae

SC Cycadidae (Cycads) characteristics

• Cycads grow very slowly

• Tropics & subtropics

• About 100 living species still exist

• Most species under severe threat in nature

• Plants produce male or female cones

• They do not produce wood of any commercial significance

SC Gingkoideae characteristics

• Fossil record shows a wide distribution across the northern hemisphere

• Only one living species, Ginkgo biloba (maidenhair tree), exists and occurs in China & Japan

• Restricted to reserves and gardens

• Deciduous tree with fanshaped leaves

Ginko biloba

• Male and female reproductive structures on different plants

• Seeds surrounded by fleshy layers with an unpleasant smell

Uses:

Female plants are highly suitable for urban planting as it is resistant to smoke and seems to be immune to disease.

The kernel of the fruit is eaten as a delicacy in the East.

Dried leaves were used for bronchitis and asthma.

Scientists are researching Ginkgo biloba as a cure for senility, hardening of the arteries and as a treatment for oxygen deprivation

Welwitschia

• Found in Namibian west coast

• Two strap-like leaves with unlimited growth from the base of the leaves

• Cones also develop from the same meristem

• Dioecious

SC Pinidae

• Order Araucariales

  • Family Araucariaceae

    • Genera Agathis

      • Leaves broad and flat

      • With short flat stalk

      • Leaving scars on the branches

  • Family Podocarpaceae

    • Genera Araucaria

      • Leaves clasping the stem and overlapping

      • Lance shaped and flat or awl shaped