phloem

or bast

Plant tissues that conduct foods made in the leaves to all other parts of the plant. Phloem is composed of several types of specialized cells, including sieve-tube cells and phloem fibers. Sieve tubes (columns of sieve-tube cells), which have perforated areas in their walls, provide the main channels in which food substances travel. Phloem fibers are long, flexible cells that make up the soft fibers used commercially (e.g., flax and hemp).

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