Rare plant species include mountain arnica Arnica Montana, swamp willow Salix myrtilloides, river birch Betula obscura, Isopyrum thalictroides, twelve Orchidaceae, Saxifraga hirculus, the aquatic species Pedicularis sceptrum-carolinum and Lathyrus laevigatus, and Hedera helix, here at the eastern limit of its range.    From Wordnik.com.  [Belovezhskaya Pushcha National Park, Belarus] Reference

Isopyrum gracilis, 153.    From Wordnik.com.  [Hardy Perennials and Old Fashioned Flowers Describing the Most Desirable Plants, for Borders, Rockeries, and Shrubberies.] Reference

Isopyrum gracilis, 153. slender, 153.    From Wordnik.com.  [Hardy Perennials and Old Fashioned Flowers Describing the Most Desirable Plants, for Borders, Rockeries, and Shrubberies.] Reference

Houstonia coerulea, Hydrangea paniculata grandiflora, Hypericum calycinum, Iris foetidissima, Isopyrum gracilis, Kalmia latifolia.    From Wordnik.com.  [Hardy Perennials and Old Fashioned Flowers Describing the Most Desirable Plants, for Borders, Rockeries, and Shrubberies.] Reference

Hydrangea paniculata grandiflora, Hypericum calycinum, Iris foetidissima, Isopyrum gracilis, Kalmia latifolia, L.thyrus grandiflorus, L. latifolius, L.num flavum, L.belia cardinalis, L.chnis chalcedonica, L. Viscaria flore-pleno, L.simachia clethroides.    From Wordnik.com.  [Hardy Perennials and Old Fashioned Flowers Describing the Most Desirable Plants, for Borders, Rockeries, and Shrubberies.] Reference

White or whitish: -- Rue-anemone, hepatica, spring beauty, blood-root, toothwort, Dutchman's breeches, dog's tooth violet, wild ginger, chickweed, Isopyrum, plantain-leaved everlasting, shepherd's purse, shad-bush, wild strawberry, whitlow-grass, wind-flower, hackberry.    From Wordnik.com.  [Some Spring Days in Iowa] Reference