Plants with yellow or green flowers
 Nuphar variegata (Yellow Pond Lily) |
 Oenothera biennis (Yellow Evening Primrose) |
 Oenothera flava (Low Yellow Evening Primrose) |
 Oenothera serrulata (Shrubby Evening Primrose) |
 Opuntia fragilis (Brittle Prickly-Pear Cactus) |
 Opuntia polyacantha (Prickly-Pear Cactus) |
 Orthocarpus luteus (Owl's-Clover) |
 Osmorhiza berteroi (Western Sweet Cicely) |
 Osmorhiza depauperata Blunt-Fruited Cicely |
 Oxytropis campestris (Early Yellow Locoweed) |
 Oxytropis monticola (Late Yellow Locoweed) |
 Packera cana (Silvery Groundsel) |
 Packera paupercula (Balsam Groundsel) |
 Parietaria pensylvanica (Pellitory) |
 Paronychia sessiliflora (Low Whitlowwort) |
 Pastinaca sativa (Wild Parsnip) |
 Pedicularis lanceolata (Swamp Lousewort) |
 Physaria arenosa (Sand Bladderpod) |
 Physaria reediana (Alpine Bladderpod) |
 Picradeniopsis oppositifolia (Opposite-Leaved Bahia) |
 Platanthera aquilonis (Green Bog Orchid) |
 Platanthera huronensis (Tall Greeen Bog Orchid) |
 Platanthera obtusata (Blunt-Leaved Bog Orchid) |
 Platanthera orbiculata (Round-Leaved Bog Orchid) |
 Polygonatum biflorum (Solomon's-seal) |
 Polygonum achoreum (Striate Knotweed) |
 Polygonum aviculare (Common Knotweed) |
 Polygonum polygaloides ssp. confertiflorum (White-Margined Knotweed) |
 Polygonum polygaloides ssp. kelloggii (Small Knotweed) |
 Portulaca oleracea (Purslane) |