Stems annual, the fertile appearing in early spring before the sterile, at first simple, at length much branched, resembling the sterile except in the withered apex; stems 8—20 inches high, producing verticillate compound branches which are curved downward; sheaths loose and cylindric, those of the stem whitish, with 8—14 rather blunt brown teeth. In moist sandy woods and thickets in the Selkirks, not common. [Sidenote: =Equisetum fluviatile= L. _Swamp Horsetail._] Stems annual, all alike, 2—4 feet high, bluish-green, smooth, usually producing upright branches after the spores are formed; sheaths appressed with about 18 dark brown or nearly black, short acute teeth. In sloughs and shallow ponds throughout the region, frequent. [Sidenote: =Equisetum hyemale= L. _Common Scouring rush._] Stems stiff, evergreen, 2—4 feet high, rough, 8—34-furrowed, the ridges with two distinct lines of tubercles; sheaths rather long, cylindric, marked with one or two black girdles, teeth dark brown or nearly black and membranous, soon deciduous; spikes tipped with a rigid point. In wet places and on banks and slides in the valley of the Kicking Horse River. [Sidenote: =Equisetum variegatum= Schl. _Variegated Equisetum._] Stems perennial, slender, evergreen, 6—18 inches long, rough, usually simple from a branched base, commonly tufted, 5—10 furrowed; sheaths companulate, distinctly 4-keeled, green variegated with black above; the teeth 5—10, each tipped with a deciduous bristle. In moist, sandy soil throughout the region up to an elevation of 7000 feet, sometimes forming large patches. [Sidenote: =Equisetum scirpoides= Michx.] Stems perennial, evergreen, very slender, 3—6 inches long, rough, flexuous and curving, growing in tufts closely matted to the ground, mostly 6-furrowed with acute ridges, simple or branching from near the base; sheaths black, with three membranous rather persistent bristle-tipped teeth. On moist sandy shaded banks throughout the Rockies. LYCOPODIACEÆ _Club-moss Family_ Branching, moss-like plants with small lanceolate or subulate, sometimes oblong or roundish simple leaves, arranged in two or many ranks on trailing or sometimes erect, usually branched stems. Sporanges solitary in the axils of the leaves or on their upper surfaces. [Sidenote: =Lycopodium Selago= L. _Fir Club-moss._] Stems usually yellowish throughout, 3—6 inches high, thick, rigid, erect, 2—5 times forked, the branches forming a level topped cluster; leaves crowded, uniform, ascending, elongated, lanceolate with a spiny tip, the upper mostly 8-ranked and sterile, those below bearing small sporanges in their axils, leaves of the lower half of the stems again sterile; plant propagated also by enlarged bud-like organs. Throughout the region in alpine meadows and slopes above 6000 feet elevation. [Sidenote: =Lycopodium annotinum= L. _Stiff Club-moss._]