What is "knee holly"

Broom \Broom\ (br[=oo]m), n. [OE. brom, brome, AS. br[=o]m; akin to LG. bram, D. brem, OHG. br[=a]mo broom, thorn?bush, G. brombeere blackberry. Cf. Bramble, n.]

1. (Bot.) A plant having twigs suitable for making brooms to sweep with when bound together; esp., the Cytisus scoparius of Western Europe, which is a low shrub with long, straight, green, angular branches, minute leaves, and large yellow flowers.

   No gypsy cowered o'er fires of furze and broom.
   --Wordsworth.

2. An implement for sweeping floors, etc., commonly made of the panicles or tops of broom corn, bound together or attached to a long wooden handle; -- so called because originally made of the twigs of the broom.

   Butcher's broom, a plant ( Ruscus aculeatus) of the Smilax family, used by butchers for brooms to sweep their blocks; -- called also knee holly. See Cladophyll.

   Dyer's broom, a species of mignonette ( Reseda luteola), used for dyeing yellow; dyer's weed; dyer's rocket.

   Spanish broom. See under Spanish.