Aerial shoots 10-30(-40) cm, from caudex-like tubers, tubers ascending to vertical. Basal leaves 1-3(-5), 1-2-ternate; petiole 5-7 cm; terminal leaflet sessile, rarely petiolulate, irregularly oblanceolate, (1.5-)2-3(-3.5) × 1-2(-2.5) cm, base narrowly cuneate, margins incised to dissected on distal 2/3, apex broadly acute, surfaces nearly glabrous; lateral leaflets 1-2×-parted and/or -lobed; ultimate lobes 4-8(-12) mm wide. Inflorescences 2-3(-5)-flowered cymes or flowers solitary; peduncle proximally nearly glabrous, distally villous; involucral bracts primarily 3, (1-)2-tiered, simple, ±similar to basal leaves, pinnatifid, 1.5-5.5 cm (primary involucral bracts 2-5.5 cm, secondary involucral bracts 1.5-3.5 cm), bases distinct, broadly to narrowly cuneate to clasping, margins irregularly serrulate and pinnatifid on ca. distal 1/2, apex narrowly acute to acuminate, surfaces thinly pilose; segments primarily 3, linear to pinnatifid; lateral segments 1-2×-parted and/or -lobed; ultimate lobes 1.5-2.5 mm wide. Flowers: sepals 8-10, pink to white, linear-oblong, 10-14(-20) × (2-)3-5(-6) mm, sparsely hairy; stamens 50-60. Heads of achenes fusiform; pedicel (5-)7-15(-22) cm. Achenes: body orbiculate, flat, 2.5-3.5 × 2-2.5 mm, not winged, densely villous; beak straight, ca. 1.5 mm, minutely puberulous, not plumose. 2 n =16.

Flowering spring (Apr-May). Rocky slopes, streamsides; 800-2500 m; Ariz., Calif., Nev., N.Mex., Tex., Utah; n Mexico.

The tuberous anemones in North America ( A . tuberosa , A . edwardsiana , A . okennonii , A . berlandieri , and A . caroliniana ) are closely related to each other and to the South American species A . decapetala Arduino, A . triternata Vahl, A . cicutifolia I.M. Johnston, and A . sphenophylla Poeppig. Particularly useful characters in identifying North American plants are number of tiers of involucral bracts, presence or absence of heterophylly between basal leaves and involucral bracts, and presence or absence of rhizomes. The current treatment of this group primarily follows C. S. Keener and B. E. Dutton (1994), who included a discussion of the relationships among its members. For a cytotaxonomic discussion of most members of this group, see C. Joseph and M. Heimburger (1966).

Duration: Perennial

Nativity: Native

Lifeform: Forb/Herb

General: Erect perennial from caudex-like tuber, tuber ascending to vertical, 2-4 cm long; stems 10-30 cm tall, glabrous below involucre to sparingly pubescent just below it, striate.

Leaves: Basal leaves 1-5, on petioles 4-7 cm long, glabrous, ternately parted and each lobe again thrice incised and toothed, blade orbicular-flabelliform in outline, 1.5-3.5 cm broad.

Flowers: Cymes 2-3 flowered, or flowers solitary; peduncle nearly glabrous below, villous above, elongating to 15-20 cm in fruit, appressed-pubescent; fruiting head ellipsoidal, 8-12 mm in diameter, 1.5-2.5 cm long, surfaces thinly pilose; sepals 8-10, pink to white, linear-oblong, 10-14 mm long, 3-5 mm wide, sparsely hairy, 50-60 stamens.

Fruits: Aggregate of fusiform achenes, 3.5-4.5 mm long, densely woolly.

Ecology: Found on rocky slopes and along streams; 2,500-5,000 ft (762-1524 m); flowers February-May.

Distribution: s CA, s NV, UT, AZ, s NM, w TX; south to n MEX.

Notes: A. tuberosa has impressive flower displays but is highly ephemeral, only flowering for a short period in early spring. It arises from an enlarged tuber and hairless, thickened, deeply-divided leaves; shoots up multiple, leafless flower stalks with terminal flowers possessing many iridescent, white to pink hairy petals, surrounding a cone of many stamens and ovaries. In fruit, the ellipsoidal head is distinctive.

Ethnobotany: Unknown, but other species in the genera have many uses.

Etymology: Anemone comes from the Greek work anemos, wind, while tuberosum means tubular or pipe-like.

Synonyms: None

Editor: SBuckley 2010, FSCoburn 2015