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[C19: from mes(o)- + Greek arkhē beginning]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
mes•arch(ˈmɛz ɑrk, ˈmɛs-, ˈmi zɑrk, -sɑrk)
1. (of a primary xylem or root) developing from both the periphery and the center; having older cells surrounded by younger cells.
2. (of a life form) originating in a habitat with a moderate moisture supply.
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