What is "bur reed"

Bur \Bur\, Burr \Burr\ (b[^u]r), n. [OE. burre burdock; cf. Dan. borre, OSw. borra, burdock, thistle; perh. akin to E. bristle (burr- for burz-), or perh. to F. bourre hair, wool, stuff; also, according to Cotgrave, ``the downe, or hairie coat, wherewith divers herbes, fruits, and flowers, are covered,'' fr. L. burrae trifles, LL. reburrus rough.]

1. (Bot.) Any rough or prickly envelope of the seeds of plants, whether a pericarp, a persistent calyx, or an involucre, as of the chestnut and burdock; a seed vessel having hooks or prickles. Also, any weed which bears burs.

   Amongst rude burs and thistles.
   --Milton.

   Bur and brake and brier.
   --Tennyson.

2. The thin ridge left by a tool in cutting or shaping metal. See Burr, n., 2.

3. A ring of iron on a lance or spear. See Burr, n.,

4. 4. The lobe of the ear. See Burr, n.,

5. 5. The sweetbread.

6. A clinker; a partially vitrified brick.

7. (Mech.)

   1. A small circular saw.

   2. A triangular chisel.

   3. A drill with a serrated head larger than the shank; -- especially a small drill bit used by dentists.

8. [Cf. Gael. borr, borra, a knob, bunch.] (Zo["o]l.) The round knob of an antler next to a deer's head. [Commonly written burr.]

   Bur oak (Bot.), a useful and ornamental species of oak ( Quercus macrocarpa) with ovoid acorns inclosed in deep cups imbricated with pointed scales. It grows in the Middle and Western United States, and its wood is tough, close-grained, and durable.

   Bur reed (Bot.), a plant of the genus Sparganium, having long ribbonlike leaves.

n. marsh plant having elongated linear leaves and round prickly fruit