Thalictrum pubescens
Thalictrum macrostylum
King-of-the-meadow, late meadow-rue, meadow-weed, muskrat-weed, pigamon pubescent, tall meadow-rue
Piedmont meadow-rue
erect, coarse, 50-300 cm.
erect to ± reclining, slender, 50-200 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 ternately and pinnately decompound;
leaflets grayish green to brownish to bright green, nearly orbiculate to ovate or obovate, apically undivided or shallowly 2-3-lobed, 5-16(-22) × 3-18 mm, length 1-3.3 times width, leathery and prominently reticulate abaxially, or sometimes quite membranous, margins sometimes revolute, lobe margins entire;
surfaces abaxially glabrous.
racemes or panicles to corymbs, apically ± rounded, many flowered;
peduncles and pedicels often pubescent.
racemes or panicles, elongate, few flowered;
peduncles and pedicels neither pubescent nor glandular.
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.
either unisexual with staminate and pistillate on different plants, or bisexual and unisexual with staminate and bisexual on some plants, pistillate and bisexual on others;
sepals 4(-6), greenish to white, nearly orbiculate, 1-2 mm;
filaments white, filiform or sometimes clavate, 1.8-4 mm, rigid to flexible;
anthers 0.5-1.2 mm.
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.
numerous, slightly stipitate;
stipe 0.3-0.7 mm;
body ovoid, 3-4.5 mm, prominently veined, glabrous;
beak 0.7-1.7 mm.
= 126.
= 56.
Thalictrum pubescens
Thalictrum macrostylum
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.)
Much variation in Thalictrum macrostylum seems to be associated with habitat differences, especially the amount of sunlight received. The name T. subrotundum merely represents plants of T. macrostylum growing in deep shade. Common garden studies and cluster analyses do not support recognition of two species (M. Park 1992).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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