PLATE FACING PAGE Mimulus Lewisii Pursh. _Red Monkey-Flower_ _Frontispiece_ 1 Pinus albicaulis Engelm. _White Pine_ 24 1 Pinus Murrayana Oreg. Com. _Jack Pine_ 24 2 Larix Lyallii Parl. _Lyall’s Larch_ 26 2 Thuja plicata Don. _Giant Cedar_ 26 3 Abies lasiocarpa (Hook) Nutt. _Balsam Fir_ 28 3 Pseudotsuga mucronata (Raf.) Sudw. _Douglas Fir_ 28 4 Tsuga Mertensiana (Bong.) Carr. _Mountain Hemlock_ 30 4 Tsuga heterophylla (Raf.) Sarg. _Hemlock_ 30 5 Picea albertiana. S. Brown. _Alberta Spruce_ 32 5 Picea albertiana. S. Brown. _Alberta Spruce_ 32 6 Zygadenus elegans Pursh. _Tall Zygadenus_ 38 6 Zygadenus gramineus Rydb. _Zygadenus_ 38 7 Stenanthella occidentalis (A. Gray). Rydb. _Stenanthium_ 40 7 Clintonia uniflora Kunth. _Clintonia_ 40 8 Tofieldia intermedia Rydb. _False Asphodel_ 42 8 Vagnera stellata (L) Morong. _Star-Flowered Solomon’s Seal_ 42 9 Erythronium grandiflorum. Pursh. _Snow Lily_ 44 10 Lilium montanum A. Nels. _Red Mountain-Lily_ 46 10 Kruhsea streptopoides (Ledeb) Kearney. _Kruhsea_ 46 11 Cypripedium passerinum Rich. _Small White Lady’s Slipper_ 54 11 Cypripedium parviflorum Salisb. _Small Yellow Lady’s Slipper_ 54 12 Corallorhiza Corallorhiza (L). Karst. _Coral-Root_ 56 12 Lyschiton kamtschatcense (L.) Schott. _Western Skunk-Cabbage_ 56 13 Cytherea bulbosa (L.) House. _Calypso_ 58 13 Orchis rotundifolia Pursh. _Small Round-Leaved Orchid_ 58 14 Limnorchis dilatatiformis Rydb. _Purplish-Green Bog-Orchid_ 62 14 Peramium Menziesii (Lindl.) Morong. _Menzies’ Rattlesnake Plantain_ 62 15 Ophrys borealis (Morong). _Northern Twayblade_ 64 15 Ophrys nephrophylla Rydb. _Heart-Shaped Twayblade_ 64 15 Cœloglossum bracteatum (Willd) Parl. _Long-Bracted Orchid_ 64 15 Limnorchis fragrans Rydb. _Fragrant White Bog-Orchid_ 64 15 Lysiella obtusata (Pursh) Rydb. _Small Northern Bog-Orchid_ 64 16 Comandra pallida DC. _White Comandra_ 74 16 Eriogonum subalpinum Greene. _Tall White Eriogonum_ 74 17 Claytonia lanceolata Pursh. _Spring Beauty_ 80 17 Claytonia parvifolia Moc. _Small-Leaved Spring Beauty_ 80