Source : Webster's Revised Unabridged Dictionary (1913)

Pineweed \Pine"weed`\, n. (Bot.)
   A low, bushy, nearly leafless herb ({Hypericum Sarothra}),
   common in sandy soil in the Eastern United States.

Source : WordNet®

pineweed
     n : annual wiry-stemmed North American weed with minute
         scalelike leaves and small yellow flowers [syn: {orange
         grass}, {nitweed}, {pine-weed}, {Hypericum gentianoides}]