Thalictrum pubescens
Thalictrum arkansanum
King-of-the-meadow, late meadow-rue, meadow-weed, muskrat-weed, pigamon pubescent, tall meadow-rue
Arkansas meadow-rue
brown, thick, tuberous.
erect, coarse, 50-300 cm.
decumbent, 20-40 cm, glabrous.
blade ternately and pinnately decompound;
leaflets light to dark green, cordate or nearly orbiculate to ovate or obovate, apically undivided to 2-3(-5)-lobed or -toothed, 11-68 × 5-70 mm, length 0.8-2.6 times width, membranous to firm, margins scarcely revolute, lobe margins entire, surfaces abaxially pubescent to glabrous.
blade 1-3x-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.
racemes or panicles to corymbs, apically ± rounded, many flowered;
peduncles and pedicels often pubescent.
terminal, racemes, few flowered.
unisexual or bisexual (sometimes bisexual with very few stamens);
sepals 4(-6), white to purplish, elliptic-rounded, 2-3.5 mm;
filaments ascending, white to purplish, filiform to distinctly clavate, 1.5-7 mm, usually rigid;
anthers 0.5-1.5(-2.1) mm, usually blunt or only slightly apiculate.
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.
numerous, sessile to stipitate;
stipe 0.5-1.5(-2.4) mm;
body ellipsoid, 3-5 mm, prominently veined, usually pubescent;
beak usually persistent, straight or coiled distally, 0.6-2.5 mm, about 1/2 length of achene body.
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.
= 126.
Thalictrum pubescens
Thalictrum arkansanum
The ovaries change from white to purplish, becoming light green, then darker green, and finally brown as fruits mature.
Because of the polymorphic nature of Thalictrum pubescens, a proliferation of names for minor morphologic variants has resulted. Field studies (M. Park 1992) have shown that too much morphologic variation occurs within populations to support the recognition of previously described taxa. Plants in New England and northeastern Canada often have a corymbose inflorescence and longer filaments and achene beaks.
This species is often incorrectly treated in floras as T. polygamum Sprengel, an invalid name.
The Iroquois used Thalictrum pubescens medicinally a a wash for head and neck, to stop nosebleeds, and to treat gall (D. E. Moerman 1986).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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