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(Botany) botany (of a xylem strand) having the first-formed xylem surrounded by that formed later, as in fern stems. Compare exarch2, endarch
[C19: from mes(o)- + Greek arkhē beginning]


(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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There will also be an artist talk today at 11am by architect and researcher at Mesarch Lab, University of Cyprus Petros Phokaides and the independent art and research collective Pick Name.
Four to six mesarch and amphicribral vascular bundles pass
It is a septate cordaitalean axis with mesarch leaf traces and a non-sympodial vasculature.
We thank Mischell Craig, Mark Mesarch, Heather Root, Frank Soto, and Lanny Wit for technical assistance.