Polygonatum x hybridum
Garden Solomon's-seal
Polygonum arenastrum
Equal-leaved Knotgrass
Polygonum aviculare
Knotgrass
Polygonum oxyspermum
Ray's Knotgrass
Polyscias fruticosa
Ming Aralia
Polyscias guilfoylei
Geranium Aralia
Pontederia crassipes
Water Hyacinth
Populus nigra
Black-poplar
Populus tremula
Aspen
Populus x canadensis
Hybrid Black-poplar
Populus x canescens
Grey Poplar
Portulaca grandiflora
Rose Moss
Portulaca oleracea
Common Purslane
Portulaca quadrifida
Pusley
Portulaca umbraticola
Wingpod Purslane
Potamogeton coloratus
Fen Pondweed
Potamogeton crispus
Curled Pondweed
Potamogeton lucens
Shining Pondweed
Potamogeton natans
Broad-leaved Pondweed
Potamogeton polygonifolius
Bog Pondweed
Potentilla anserina
Silverweed
Potentilla erecta
Tormentil
Potentilla gracilis
Graceful Cinquefoil
Potentilla indica
Yellow-flowered Strawberry