Palm trees (family Palmae or Arecaceae) are
familiar in many warmer regions, and are
grown for their wood, frond-like leaves and
nut-like or juicy seeds that produce oil, starch
and other useful materials, as well as
providing edible dates and coconuts. A
typical palm has an un branched, almost
straight trunk covered with ring-, arc- or
scale-like scars where leaf bases were once
attached. The trunk cannot grow thicker
like most other trees but remains almost the
same diameter to the crown of frond-like
leaves, which may be fan-like, feathery or
fern-like. Palm fossils of genera such as
Saba/ and Palmoxy/on are known from
the Late Cretaceous Period,80-plus million
years ago. By the Early Tertiary Period,
60 million years ago, they were evolving
fast, and living genera such as Phoenix (date
palms) and Nypa (mangrove palms) had
appeared. There are hundreds of extinct
species and more than 2,700 living ones.