Smooth, pale green, and glaucous; stem purplish, erect, 6—18 inches tall. Leaves 3—4, ternate, long-petioled, leaflets firm, obovate, rounded at the apex, wedge-shaped or subcordate at the base, ¼—½ an inch long, 3—5-lobed, the lower surface prominently veined. Flowers diœcious, with 4 or 5 small, purplish-green sepals and large, linear, wedge-shaped anthers or slender styles; the achenes wedge-shaped and tapering into a short beak. A frequent plant in the dry open valleys in the Rockies at the lower altitudes; flowering in June. [Sidenote: =Thalictrum occidentale= A. Gray. _Western Meadow Rue._] Stems slender, 1—3 feet high. Leaves 2—4, ternate, the lowest petioled; leaflets thin, ¼ to nearly an inch long, 3—9 lobed at the summit, sparingly glandular-hairy beneath. Flowers diœcious, nodding on very slender pedicels in an ample open panicle; calyx of 4—8 sepals which soon fall, filaments purplish and slender; anthers linear and pointed; achenes lanceolate or somewhat sickle-shaped, nearly half an inch long. Frequent in rich woods and moist shady places at the lower altitudes throughout the Rockies; flowering in June, like the previous species striking for its leaves, resembling a robust maiden-hair fern, and the large loose heads of delicate tasselled flowers. [Illustration: Thalictrum megacarpum Torr. (⅓ Nat.)] [Illustration: Thalictrum occidentale A. Gray. (⅓ Nat.) Western Meadow Rue.] [Sidenote: =Batrachium trichophyllum= (Chaix.) Bossch. _White Water Crowfoot._] Aquatic herb with submerged stems, a foot long or more. Leaves petioled, 1—2 inches long, finely dissected. Flowers white with yellow centre, ½—¾ of an inch broad, blooming on the surface of the water on stout pedicels 1—2 inches or more long. Frequent throughout the Rockies at the lower altitudes in shallow ponds and ditches; flowering in June and July. [Sidenote: =Ranunculus Purshii= Richards. _Pursh’s Buttercup._] Aquatic or creeping, hairy, at least on the younger parts. Leaves slender-petioled, ¼—1 inch, wide, palmately divided nearly to the base, into obtuse lobes. Flowers less than ½ an inch broad, bright yellow; petals 5; head of fruit globose, a little less than ¼ of an inch broad. Frequent in shallow pools throughout the Rockies; flowering throughout the summer. [Sidenote: =Ranunculus reptans= L. _Creeping Spearwort._] Stems creeping, rooting at the joints; flowering stems and peduncles ascending. Leaves linear-lanceolate or spatulate ½—2 inches long, entire, gradually narrowed into the petiole. Flowers nearly half an inch broad, solitary, on peduncles ¾—2 inches long; petals 4—7, much exceeding the calyx; stamens numerous; achenes flat. On muddy shores of ponds and streams throughout the Rockies, flowering in midsummer, the creeping stems frequently interlaced and forming dense mats. [Illustration: _a_ Ranunculus eremogenes Greene. Ditch Crowfoot. _b_ Ranunculus Purshii Richards. (⅓ Nat.) Pursh’s Buttercup.]