knot·grass 
(nŏtgrăs′)
(nŏtgrăs′)n.
1. A low-growing, weedy grass (Paspalum distichum) with spikelets arranged in two rows along the rachis.
2. Any of several weedy plants of the genus Polygonum having stems with nodes.
- throw a bone
- throw a curve ball
- throw away
- throwaway
- throw back
- throwback
- throw cold water on
- thrower
- throw for a loop
- throw hat into the ring
- throw in
- throw-in
- throw in the sponge
- throw in the towel
- throw in the towel/sponge
- throw light on
- thrown
- throw off
- throw oneself at
- throw one's hat into the ring
- throw (one's) weight around
- throw one's weight around
- throw open
- throw out
- throw over