Australia

Part I of Essay
Although only a dozen plant families are unique to , there are 530 unique genera and many unique species within these genera. As the n fragment of prehistoric Gondwanaland drifted north, its ancient flora became the basis for the present plant systems. Increasing aridity mo ....

Part II of Essay
.... trees, is the most ubiquitous, forming a wide, concentric band around the desert core. Of the 500 species, two or three typically form a mosaic in one locality and intermingle with other plant associations. Eucalyptus trees are classified according to their bark types--hence the names stringybark, ironbark, bloodwood, and smoothbark (the gums that shed their outer bark annually). The most widespread is the river red gum. Mallee eucalypts survive in semiarid regions by growing multiple stems (lignotubers) from a common rootstock. The wor ....