WordNet (r) 3.0 (2006):

greens
    n 1: any of various leafy plants or their leaves and stems eaten
         as vegetables [syn: greens, green, leafy vegetable]

Moby Thesaurus II by Grady Ward, 1.0:

32 Moby Thesaurus words for "greens":
   Irish potato, Kraut, aubergine, beans, botany, cabbage, eggplant,
   flora, flowerage, greenery, herbage, legumes, love apple,
   mad apple, pieplant, plant kingdom, plant life, plants, potato,
   potherbs, produce, rhubarb, spud, tater, tomato, vegetable kingdom,
   vegetable life, vegetables, vegetation, vegetation spirit, verdure,
   white potato