Lesser Meadow Rue

In Great Britain and/or Ireland:
Foodplant / parasite
Erysiphe aquilegiae var. ranunculi parasitises Thalictrum minus

Foodplant / saprobe
immersed pycnidium of Phoma coelomycetous anamorph of Phoma jacquiniana is saprobic on dead stem of Thalictrum minus
Remarks: season: 1-7

Foodplant / parasite
Podosphaera thalictri parasitises Thalictrum minus

Foodplant / parasite
aecium of Puccinia recondita parasitises live Thalictrum minus

Foodplant / parasite
almost always hypophyllous telium of Tranzschelia anemones parasitises live leaf of Thalictrum minus
Other: unusual host/prey

Foodplant / false gall
Urocystis sorosporioides causes swelling of stem of Thalictrum minus
Remarks: season: 6
Other: minor host/prey

Thalictrum minus has been reported from mainland Alaska (E. Hultén 1968); we have been able to confirm its occurrence only in the Aleutian Islands.

Initially pendent, the flowers become erect. The beak is 0.75-1 mm, much shorter than the achene, and not fimbriate.

Stems erect, nearly cespitose or rhizomatous, 15-150 cm, glabrous or somewhat glandular. Leaves basal, 7-30 cm. Leaf blade 3-4-ternate; leaflets nearly orbiculate or broadly ovate, irregularly 2-3-lobed or margins dentate in distal 1/2, 15-30 mm, surfaces glabrous to glandular. Inflorescences panicles with long branches, many flowered. Flowers: pedicels not recurved in fruit; sepals yellowish green, ovate, 3-4 mm; stamens 10-15; anthers yellowish, 2-3 mm. Achenes 3-15, sessile; body broadly ovoid to narrowly oblong-ovoid, 2.5-4 mm, ± weakly veined.

Plants glabrous. Cauline leaf petiole ca. 4 cm; leaf blade 4-ternate or -pinnate, ca. 20 cm; leaflet blade cuneate-obovate, broadly obovate, orbicular, or narrowly rhombic, 0.7--4(--5) × 0.4--4(--5) cm, papery or thinly leathery, abaxially greenish, sometimes powdery white, base cuneate to rounded, margin 3-lobed; veins raised abaxially, sometimes inconspicuous. Inflorescence paniculate, ca. 30 cm. Pedicel 3--30 mm. Sepals 4, deciduous, greenish tinged, narrowly elliptic, ca. 3.5 mm. Stamens many, ca. 6 mm; filament filiform; anther narrowly oblong, ca. 2 mm, apex mucronate. Carpels 3--5; stigma triangular winged. Achenes sessile; body narrowly ellipsoid, ca. 3.5 mm; veins ca. 8. Fl. Jun--Jul.

Alaska; Eurasia.

Anhui, Gansu, Guangdong, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jilin, Liaoning, Nei Mongol, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Xinjiang [temperate Asia and Europe].

Flowering late spring-summer (Jun-Jul).

Steppe meadows, shrub thickets, forest margins, and forest meadows; 0-300m.

Forests, scrub, mountains, slopes, damp rocky ledges, field margins; 1400--2700 m.

Thalictrum minus subsp. kemense (Fries) Hultén; T. minus var. stipellatum (C. A. Meyer) Tamura

Thalictrum minus, known as lesser meadow-rue, is a perennial herb in the family Ranunculaceae that is native to Europe, Northwest Africa, Yemen, Ethiopia, South Africa, Southwest Asia, and Siberia. It grows on sand dunes, shingle, coastal rocks or calcareous grassland, cliffs and rocky gullies at up to 1,600 to 3,000 m (5,200 to 9,800 ft) elevation at southern latitudes. It grows to 30 cm (0.98 ft) tall with erect stems and 1 cm (0.39 in) leaves that are highly subdivided, 3-4 ternate to pinnate.

The plant contains an alkaloid 'Thalidisine', which is also present in other Thalictrum species.