| The Cycad {sy'-kad} |
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 The
Cycad species has the rare privilege of having survived at least 200
million years of the earth's history. Cycads apparently evolved from
the Cycadofilicales ("seed ferns") late in the Pennsylvanian
Period, about 300 million years ago. They were widespread during the
Mesozoic era, some 65 to 225 million years ago, when the Dinosaurs
were one of the dominant life forms. Judging from rarely found fossil
cones it appears that cycads have changed relatively little in the
last 100 million years which is why modern cycads are called
"living fossils".
Some cycads have a superficial resemblance to palms, others to
ferns. The distinctive features of the plant are large, pineapple-like
cones that protrude from the top of the stem and contain fleshy seeds.
The plant's sex is determined by the cones,
which are either pollen-bearing male, or seed-bearing female. This
makes the Cycad a member of the more primitive gymnosperm family, also
known as "naked seed" or "nonflowering seed"
plants. They are pollinated by insects, not by wind as had been
previously thought; their cones generate heat that vaporizes a sweet
minty odor to attract
insects to a supply of nectarlike liquid. The tallest cycad
(Macrozamia hopei) on record was about 18 m (60 ft).
Cycads are found today in tropical, subtropical and warm, temperate
areas. There are more than 70 living species of cycads. Some species
are locally abundant in Mexico, others are found only in western Cuba
(where it is in danger of becoming extinct). The largest and most
widely distributed genus is Zamia which ranges from the sandy
woods of Florida and the West Indies through Central America and the
Andes into Chile. Most African Cycad
species, Encephalartos and
Stangeria
are found only in Southern Africa along the Southern Coastal
regions of South Africa. Here the plant has a high profile due to
extensive poaching from its natural habitat. In the Western Cape region a large
collection of Cycads is held at the Kirstenbosch
Botanical Gardens. In Australia, two genera, Macrozamia
and Bowenia, are found only in New South Wales and
Queensland. Cycas (about 15 species) is widely distributed ranging
from Australia to the Pacific islands in the north and to India,
China, Japan, and Madagascar.
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