The Collaborative International Dictionary
Mesophloeum
Mesophloeum \Mes`o*phl[oe]"um\, n. [NL., fr. Gr. me`sos middle + floio`s bark.] (Bot.) The middle bark of a tree; the green layer of bark, usually soon covered by the outer or corky layer, and obliterated.
Wiktionary
mesophloeum
n. (context botany English) The middle bark of a tree; the green layer of bark, usually soon covered by the outer or corky layer, and obliterated.