There has been in effect a successive shifting of zones of vegetation southwards from the pole.
The design consists of five different zones on each lens.
She'd traveled nonstop, sticking to narrow country roads and the forest to avoid both people and zones marked as having any sort of radiation fallout from the nuke strikes.
The flora of Argentina should be studied according to natural zones corresponding to the physical divisions of the country - the rich tropical and sub-tropical regions of the north, the treeless pampas of the centre, the desert steppes of the south, and the arid plateaus of the north-west.
An ordinary cambium is scarcely ever found in the Monocotyledons, but in certain woody forms a secondary meristem is formed outside the primary bundles, and gives rise externally to a little secondary cortex, and internally to a secondary parenchyma in which are developed numerous zones of additional bundles, usually of concentric structure, with phloem surrounded by xylem.