Thalictrum occidentale

A. Gray

Proc. Amer. Acad. Arts 8: 372. 1873.

Common names: Western meadow-rue
EndemicIllustrated
Synonyms: Thalictrum occidentale var. macounii B. Boivin Thalictrum occidentale var. palousense H. St. John
Treatment appears in FNA Volume 3.

Roots yellow to medium brown or black, thin, fibrous. Stems erect, 30-100 (-120) dm, glabrous, often from well-developed rhizomes. Leaves mostly cauline. Leaf-blade 3-4×-ternately compound; leaflets orbiculate to obovate-cuneate or cordate, apically 3-lobed, 10-30 mm wide, lobe margins coarsely crenate, surfaces glabrous to glandular. Inflorescences terminal (some flowers in axils of distal leaves), panicles, rather open, many flowered. Flowers: sepals whitish or greenish or purplish tinged, ovate, 3.5-4.4 mm in staminate flowers, 1.5-2 mm in pistillate flowers; filaments purplish, 4-10 mm; anthers 1.5-4 mm, long-apiculate; stigma often purplish. Achenes 6-9, spreading to reflexed, short-stipitate; stipe 0.4-1.2 mm; body fusiform, not laterally compressed, (4-) 6-9 (-10) mm, tapering at both ends, glandular, strongly 3-veined on each side, veins not anastomosing; beak 3-4.5 (-6) mm.


Phenology: Flowering early summer-mid summer (Jun–Aug).
Habitat: Open woods, meadows, and copses
Elevation: 200-3400 m

Distribution

V3 982-distribution-map.gif

Alta., B.C., Sask., Yukon, Alaska, Calif., Colo., Idaho, Mont., Nev., N.Dak., Oreg., Utah, Wash., Wyo.

Discussion

Thalictrum occidentale is similar to T. confine and T. venulosum; thorough field studies are needed to determine whether or not they should be maintained as separate species. Thalictrum occidentale can usually be distinguished by its reflexed achenes.

Plants of northern British Columbia, sometimes called Thalictrum occidentale var. breitungii (B. Boivin) Brayshaw, appear to be intermediate between T. occidentale and T. venulosum (T. C. Brayshaw, pers. comm.); achenes are ascending, ± compressed, and beaks rather short (2-4 mm) (T. C. Brayshaw 1989).

Some of the Native Americans used Thalictrum occidentale medicinally for headaches, eye trouble, and sore legs, to loosen phlem, and to improve blood circulation (D. E. Moerman 1986).

Selected References

None.

Lower Taxa

None.

"dm" is not declared as a valid unit of measurement for this property.

... more about "Thalictrum occidentale"
short-stipitate +
spreading +  and reflexed +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
Marilyn M. Park +  and Dennis Festerling Jr. +
A. Gray +
cuneate +, truncate +  and cordate +
Heterogamia +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
straight +
0.3 cm3 mm <br />0.003 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
0.9 cm9 mm <br />0.009 m <br /> (1 cm10 mm <br />0.01 m <br />) +
tapering;compressed;fusiform +
0.6 cm6 mm <br />0.006 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
globose;cylindric +
Western meadow-rue +
Alta. +, B.C. +, Sask. +, Yukon +, Alaska +, Calif. +, Colo. +, Idaho +, Mont. +, Nev. +, N.Dak. +, Oreg. +, Utah +, Wash. +  and Wyo. +
200-3400 m +
0.4 cm4 mm <br />0.004 m <br /> (1 cm10 mm <br />0.01 m <br />) +
pistillate +  and staminate +
showy +  and inconspicuous +
unisexual +
0 cm0 mm <br />0 m <br /> (41 cm410 mm <br />0.41 m <br />) +
stipitate +, sessile +  and aggregate +
falcate;ovoid;obovoid +
Open woods, meadows, and copses +
compound +  and simple +
whorled +, opposite +  and alternate +
3-lobed +, orbiculate +  and obovate-cuneate or cordate +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
palmate +  and pinnate +
crenate;entire +
flowered +  and open +
distinct +
conspicuous +
reduced +
Flowering early summer-mid summer (Jun–Aug). +
1 +  and 16 +
Proc. Amer. Acad. Arts +
well-developed +
yellow;medium brown or black +
not arillate +  and stalked +
purplish tinged;greenish;whitish +
not persistent +
distinct +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
ribbed +  and veined +
Endemic +  and Illustrated +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
persistent +
glabrous;glandular +
Thalictrum occidentale var. macounii +  and Thalictrum occidentale var. palousense +
Thalictrum occidentale +
Thalictrum sect. Heterogamia +
species +
not anastomosing +
herbaceous +  and woody +