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Webster 1913 Edition

Noun.

The part of a tree which lies immediately under the bark; the alburnum or sapwood.

Noun.

The part of a tree, which lies immediately under the bark.

blea ‎(uncountable)

The part of a tree that lies immediately under the bark; the alburnum or sapwood.
- 1814, Benjamin Smith Barton, Elements of Botany
  Authors differ greatly in opinion concerning the formation of the blea. Linnaeus imagined it was formed by the bark. But it is certain that the whole of the bark does not give birth to the blea […]