Thalictrum arkansanum

B. Boivin

Rhodora 46: 433. 1944.

Conservation concernEndemic
Treatment appears in FNA Volume 3.

Roots brown, thick, tuberous. Stems decumbent, 20-40 cm, glabrous. Leaves: distal cauline long-petiolate. Leaf-blade 1-3×-ternately compound; leaflets ovate to obovate to reniform or orbiculate, 3- (or more) -lobed, largest leaflets less than 15 mm wide, lobe margins crenate, surfaces glabrous. Inflorescences terminal, racemes, few flowered. Flowers: sepals whitish, ovate or elliptic, 0.9-2.8 (-3) mm; filaments colored, 2-3 mm; anthers 1.8-2.3 mm, mucronate, tip 0.1-0.4 mm; stigma color unknown. Achenes few, not reflexed, nearly sessile; stipe 0.1-0.3 mm; body ellipsoid to oblong, 3.5-4.5 × 1.5-2 mm, glabrous, veins 10-12, not anastomosing-reticulate; beak (1.3-) 2.3-3 mm.


Phenology: Flowering early spring (Mar–Apr).
Habitat: Wet bottomland forest, sometimes upland woods
Elevation: 20-150 m

Discussion

Of conservation concern.

Poorly known, Thalictrum arkansanum is closely related to T. texanum and T. debile; it possibly should be considered as a variety of the latter.

Selected References

None.

Lower Taxa

None.
... more about "Thalictrum arkansanum"
not reflexed +
mucronate +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.23 cm2.3 mm <br />0.0023 m <br />) +
Marilyn M. Park +  and Dennis Festerling Jr. +
B. Boivin +
cuneate +, truncate +  and cordate +
Heterogamia +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.23 cm2.3 mm <br />0.0023 m <br />) +
straight +
0.23 cm2.3 mm <br />0.0023 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
ellipsoid;oblong +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
globose;cylindric +
Ark. +, Okla. +  and Tex. +
20-150 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 +
Wet bottomland forest, sometimes upland woods +
0 cm0 mm <br />0 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
compound +  and simple +
whorled +, opposite +  and alternate +
cauline +  and basal +
3-lobed +, ovate +  and obovate +
palmate +  and pinnate +
crenate;entire +
(1-)2-200-flowered +
distinct +
conspicuous +
reduced +
Flowering early spring (Mar–Apr). +
1 +  and 16 +
not arillate +  and stalked +
0.28 cm2.8 mm <br />0.0028 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
not persistent +
distinct +
elliptic +  and ovate +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.28 cm2.8 mm <br />0.0028 m <br />) +
ribbed +  and veined +
Conservation concern +  and Endemic +
20 cm200 mm <br />0.2 m <br /> (40 cm400 mm <br />0.4 m <br />) +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
persistent +
Thalictrum arkansanum +
Thalictrum sect. Heterogamia +
species +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
not anastomosing-reticulate +
10 +  and 12 +
herbaceous +  and woody +