Herbaceous plants, often swollen at the nodes, with opposite entire leaves and perfect or rarely diœcious regular flowers; sepals 4 or 5 persistent, separated or united into a calyx tube; petals equal in number to the sepals or none; stamens twice as many as the sepals or fewer.

Closely tufted, an inch or two high, forming cushion-like beds, often 2 feet or more across. Leaves sessile, crowded, linear, ½ an inch or less long, the margins ciliate. Flowers ¼ of an inch or more across, nearly sessile or raised on naked curved peduncles, often ½ an inch long; calyx narrowly campanulate, ¼ of an inch long, smooth, the teeth short, rounded; petals rose-purple or rarely white, entire or notched.

In alpine meadows, in stony ground, on the moraines and tops of the mountains throughout the region, flowering in June and July.

Stems slender, decumbent at the base, 12—18 inches high, minutely hairy throughout, glandular above. Leaves, the basal spatulate, obtuse 1—2 inches long on long petioles, those of the stem linear 1—2 inches long, sessile. Flowers on short peduncles in rather loose terminal heads; calyx oblong, inflated, about ½ an inch long, narrow, glandular, teeth purple-tipped; petals white, nearly half an inch long, spreading, two-lobed.

On grassy alpine slopes throughout the region, flowering in June and July.

More or less glandular-hairy, 2—6 inches high. Leaves linear or oblanceolate, ½-2½ inches long. Flower solitary, ½—¾ of an inch long, nodding; calyx inflated, strongly purple veined, its teeth triangular-ovate, acute; petals purple, as long as or shorter than the calyx, narrow, 2-cleft.

Among loose boulders on the moraines and alpine summits throughout the region, flowering in July.

Stems tufted, ascending from a decumbent base, 3—6 inches high, hairy throughout, roughly so at the base; glandular at the summit. Leaves numerous, ½—¾ of an inch long, narrowly lanceolate, acute, with a broad sessile base. Flowers several in a more or less close head, nearly half an inch broad, white; petals deeply notched.

In dry stony ground in the lower valleys of the Rockies, flowering in June.

Thick, silky-hairy below, with sticky hairs above; stems matted 1—3 inches high. Leaves small, oblong, ¼ of an inch long or less, rather thick, obtuse. Flowers ¼ of an inch or more broad; petals white, notched at the apex, sometimes little longer than the lanceolate sepals.

In stony ground, alpine slopes and summits throughout the Rockies, flowering during summer.

Erect or ascending, tufted, simple or rarely sparingly branched, 3—12 inches high, smooth and shining. Leaves light green, lanceolate or linear-lanceolate, ½—1½ inches long, broad at the base. Flowers few, ¼—⅓ of an inch broad, terminal, on long, slender, erect pedicels; sepals ovate or lanceolate, acute; petals 2-cleft, exceeding the calyx.

In moist open places throughout the Rockies, flowering in June.

Low, smooth, or somewhat hairy, 1—4 inches high, very glaucous throughout, densely leafy at the base. Leaves keeled, lanceolate, awl-shaped to linear, rather stiff, ¼—½ an inch long. Flowers ¼ of an inch or more across; sepals lanceolate, acute, ⅛ of an inch long; petals notched, longer than the sepals; stamens showy, with scarlet anthers.

In alpine meadows and moist grounds at high altitudes, throughout the region; flowering in July.

Erect or ascending, weak, much branched, smooth, or hairy above, 6—18 inches long. Leaves thin, lanceolate or oblong-lanceolate, ½—1½ inches long, acute, sessile, thin, margins slightly hairy or naked. Flowers small and inconspicuous in a leafy terminal compound head, ascending or spreading on slender pedicels; sepals ovate-lanceolate, acute; petals shorter than the sepals or none.

In wet places at the lower altitudes throughout the Rockies; flowering throughout the summer from early June.

Smooth, stems very slender and tufted, 1—4 inches high. Leaves 1⅛ to nearly ½ an inch long with a spiny tip. Flowers small, solitary or few together, at the end of the slender stem, about ⅛ of an inch broad; petals white minute, hardly exceeding the calyx.

On rocks and moist sandy ground throughout the region; flowering in June.

Stems erect or ascending, simple or at length, sparingly branched, finely hairy throughout, 4—12 inches high. Leaves thin, oval, or oblong, ½—1 inch long, obtuse, spreading, the margins and nerves fringed with hairs. Flowers few in lateral and terminal clusters or sometimes solitary; ¼ of an inch or more broad, their parts in 4’s or 5’s; sepals oblong, obtuse or acute, half as long as the nearly entire white petals.

In moist places growing among grass, throughout the Rockies; flowering in June.

Smooth throughout except the tops of the stems and sepals, which are glandular; stems slender, 4—8 inches high, numerous from a tufted, leafy base. Leaves mostly in bundles ½—1½ inches long, smooth, very slender and curved, with a spiny tip, those of the stem few and much reduced. Flowers white, ½ an inch broad in a loose branching head.

A rather striking plant on grassy slopes throughout the region; flowering in June.

Very slender, much branched and finely, sticky-hairy throughout; stems thread-like, numerous, nearly of a uniform length in the same plant, 2—3 inches long. Leaves crowded at the base, few and much reduced above, linear, awl-shaped, thick, semi-cylindric, nearly smooth. Flowers small, little more than ⅛ of an inch across; sepals ovate-oblong, acute, strongly 3-nerved; petals white, acute, not exceeding the sepals.

A small tufted plant with wiry stems and minute white star-like flowers, in moist or dry, sandy places throughout the region from the low valleys to the alpine summits; flowering in May and June.

Closely tufted, stems densely glandular-hairy, decumbent, very leafy below, ½—2½ inches long with 2 or 3 pairs of short, rather distant leaves and terminating in 1—3 flowers. Lower leaves, linear-obtuse, stiff, ⅛ of an inch or more long, smooth or slightly hairy; calyx lobes linear-oblong, 1—3 ribbed, glandular, hairy, ⅛ of an inch long; petals white, broad, equalling or exceeding the sepals.

On high alpine slopes and summits, throughout the Rockies; flowering in June and July.