Thalictrum heliophilum

Wilken & DeMott

Brittonia 35: 156. 1983.

Conservation concernEndemicIllustrated
Treatment appears in FNA Volume 3.

Roots fibrous. Stems 14-50 cm, arising singly or in dense clusters of 2-3 from short, horizontal, fibrous-rooted rhizomes. Leaves basal and cauline, petiolate. Leaf-blade ternately compound, cauline blades gradually reduced upward, distalmost 2-ternate; leaflets broadly obovate, apically 3-toothed, otherwise undivided, 5-8 × 4-5 mm, leathery, surfaces glabrous, glaucous. Inflorescences terminal, panicles, many flowered. Flowers: sepals 4, color unknown, lanceolate to ovate, 2-3 mm; filaments brownish, 2-3 mm; anthers 2-3 mm, apiculate; stigma color unknown. Achenes 4-5 (-6), not reflexed, nearly sessile; stipe 0.1-0.2 mm; body oblique-obovate, strongly laterally compressed, 4-5 mm, glabrous, glaucous, prominently 3-veined on each side, veins converging near apex, rarely branched or sinuous, not anastomosing-reticulate; beak ca. 1.5 mm.


Phenology: Flowering summer–summer (Jun–Aug).
Habitat: Decomposing shale of Green River Formation
Elevation: 2500 m

Discussion

Of conservation concern.

In a genus of primarily mesophytic plants, Thalictrum heliophilum is notable for its relatively xeric habitat. Known only from Garfield and Rio Blanco counties, northwestern Colorado, it is similar to the widespread T. fendleri; it may be distinguished by its smaller, leathery, glaucous leaflets and fewer achenes.

Selected References

None.

Lower Taxa

None.
... more about "Thalictrum heliophilum"
not reflexed +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
Marilyn M. Park +  and Dennis Festerling Jr. +
Wilken & DeMott +
cuneate +, truncate +  and cordate +
Heterogamia +
straight +
1.5 cm15 mm <br />0.015 m <br /> (?) +
glaucous +  and glabrous +
compressed;oblique-obovate +
0.4 cm4 mm <br />0.004 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
globose;cylindric +
2500 m +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
sessile +  and pedicellate +
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 +
Decomposing shale of Green River Formation +
whorled +, opposite +  and alternate +
cauline +  and basal +
0.5 cm5 mm <br />0.005 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
3-toothed +  and obovate +
0.4 cm4 mm <br />0.004 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
palmate +  and pinnate +
crenate;entire +
distinct +
conspicuous +
reduced +
Flowering summer–summer (Jun–Aug). +
1 +  and 16 +
fibrous-rooted +
not arillate +  and stalked +
lanceolate;ovate +
not persistent +
distinct +
lanceolate +  and reniform or spatulate +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
ribbed +  and veined +
Conservation concern +, Endemic +  and Illustrated +
in dense clusters +  and singly +
2 +  and 3 +
14 cm140 mm <br />0.14 m <br /> (50 cm500 mm <br />0.5 m <br />) +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
persistent +
glaucous;glabrous +
Thalictrum heliophilum +
Thalictrum sect. Heterogamia +
species +
not anastomosing-reticulate +
sinuous +
herbaceous +  and woody +