Erect, usually branching, very smooth below, 6—18 inches high. Leaves mostly sessile, 1—2 inches long, ¼—½ an inch wide, denticulate or entire, lanceolate or ovate-lanceolate, acutish at both ends, thick, those of the branches opposite, the veins inconspicuous. Flowers reddish-purple, 1—2 inches broad, mainly in short leafy-bracted racemes; petals entire; stigma 4-lobed. On gravelly river bars and moist clayey banks throughout the entire region; flowering during July. [Illustration: _a_ Epilobium luteum Pursh. Yellow Willow-herb. (⅗ Nat.) _b_ Chamænerion latifolium (L.) Sweet. Broad-Leaved Willow-herb.] [Sidenote: =Epilobium luteum= Pursh. _Yellow Willow-herb._] Stems rather stout, 1—2 feet high, usually simple, nearly smooth. Leaves 1—3 inches long, ovate or elliptical to broadly lanceolate, acute or acuminate, sinuate-toothed, sessile, or when large, obliquely tapering to a winged petiole, slightly fleshy. Inflorescence with more or less glandular pubescence; flowers about ¾ of an inch long, not opening widely, pale yellow, rather few, at first nodding in the axils of the upper leaves; style usually exserted and deeply 4-parted. A rather rare plant in springy places and along alpine brooks, confined to the Selkirks: flowering during July. [Sidenote: =Epilobium alpinum= L. _Alpine Willow-herb._] Slender, smooth or nearly so, 3—12 inches high. Leaves pale, petioled, opposite or the upper alternate, obtuse or obtusish at the apex, ½—¾ of an inch long. Flowers, few, white, nearly erect, ¼ of an inch or more broad; stigma nearly entire; capsules slender stalked, 1—2 inches long, seeds beaked. In damp and springy places at the higher altitudes throughout the region; flowering in July. [Sidenote: =Epilobium anagallidifolium= Lam. _Nodding Willow-herb._] Low, usually tufted, 2—6 inches high, slender, smooth or nearly so; stems commonly hairy in lines and nodding at the apex. Leaves oblong or narrowly ovate, entire or nearly so, obtuse at the apex, narrowed at the base into a short petiole ½—1 inch long. Flowers few, axillary, clustered at the apex, pink-purple, nodding, about ¼ of an inch broad; stigma entire. On damp stones and along alpine brooks at high elevations throughout the region; flowering during midsummer. [Illustration: Berberis aquifolium Pursh. (¼ Nat.) Trailing Mahonia.] [Illustration: Chamænerion angustifolium (L.) Scop. (½ Nat.) Fire-Weed.] [Sidenote: =Epilobium Hornemanni= Reichb. _Hornemann’s Willow-herb._] Erect, 6—12 inches high, simple or nearly so, slightly hairy above, otherwise smooth. Leaves short-petioled, ovate or elliptic, mostly, broadly obtuse at the apex, narrow or rounded at the base, entire or rather remotely denticulate, thin, ½—1¼ inches long. Flowers few in the upper axils, pink-purple or violet, ¼ of an inch or more broad; stigma entire.