Linum narbonense, the perennial flax or blue flax, is a flowering plant in the family Linaceae, native to Europe and similar in appearance to Linum perenne.

Growing to 1–2.5 feet tall and 1 foot wide, the stem terminates in a cyme of about ten clear blue flowers with five petals, 2–2.5 cm in diameter, and the small, narrow grayish green leavesk are arranged on the stem in whorls. In early summer it produces teardrops buds. The seed heads are small beige balls.

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