Herbs with alternate, compound or simple leaves; flowers small, white, yellow or purple in compound flat heads; fruit dry, usually of two flattened carpels.

Nearly stemless, 4—24 inches high, more or less hairy, much branched at the base from an elongated thick root. Leaves pinnately compound, segments pinnately-incised, on rather short petioles, purplish at the base; flowers white or pinkish in a somewhat equally 3—10-rayed umbel; rays 1—4 inches long.

In dry stony ground throughout the Rockies, very abundant on the lower ridges in the vicinity of Banff; flowering in early June.

Purplish at the base, with or without stems, 1—2 feet high, slightly hairy. Leaves twice or thrice ternate, the leaflets narrowly linear, 2—4 inches long. Flowers small, deep yellow in an unequal umbel of 5—18 rays, with slender bracts.

Through the Rockies on dry ridges and grassy slopes; flowering in early June.

Stems 1—3 feet high, very leafy at the base, from a large fleshy rootstock. Leaves ternate or thrice pinnate, segments very finely cut. Flowers small, brownish-purple in nearly equal 8—20 rayed, rounded umbels, 3—4 inches in diameter, usually without an involucre.

A most striking plant from its beautifully dissected leaves and rather large heads of rich brownish-purple flowers blossoming in June; on grassy slopes of Stony Squaw, Banff.

Stout, erect, branched, and smooth or somewhat hairy, 1—2 feet high. Basal and lower leaves long-petioled, broadly ovate or orbicular, undivided, deeply cordate at the base, 1—3 inches long, crenate; stem leaves short-petioled, ternate, the segments ovate or oval, crenate or lobed. Flowers small, bright yellow, in nearly flat 7—16 rayed umbels, 1—2 inches in diameter.

Common on the eastern slopes and foothills of the Rockies; flowering in May and early June.

Smooth throughout except the slightly hairy inflorescence and rough leaf margins; stems 2—3 feet high with 1—3 rather small leaves with inflated petioles. Leaves ternately divided, the segments usually distinct, ovate, deeply cleft into linear acute, sharply serrate or entire lobes. Flowers white in nearly flat, many rayed umbels, 2—3 inches in diameter.

Abundant in wet places and along streams through the Selkirks, especially so in the Asulkan Valley at Glacier; flowering in June and July.

Very stout, soft-hairy, 4—8 feet high, the stems rigid, often 2 inches thick at the base. Leaves petioled, ternately divided, very hairy beneath, the segments broadly ovate or orbicular, cordate, stalked, lobed or sharply serrate, rather thin, 3—6 inches broad; petioles much inflated. Flowers white in 8—30 rayed umbels, 6—12 inches broad, the rays stout, 2—4 inches long.

Common throughout the region in wet places along streams and river banks, frequently growing in great masses; flowering in June and July.