Vascular Plants of North Carolina
Account for Waxyleaf Meadow-rue - Thalictrum amphibolum   Greene
Members of Ranunculaceae:
Members of Thalictrum with account distribution info or public map:
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Section 6 » Family Ranunculaceae
AuthorGreene
DistributionThroughout the Mountains, and essentially throughout the Piedmont; in the Coastal Plain limited mainly to a few places close to the Fall Line, but not in the Sandhills region. It is absent in most of the Coastal Plain.

This is a widespread species across eastern North America. It ranges from southeastern Canada south to northern FL and eastern TX. It is scarce, however, on the Atlantic Coastal Plain.
AbundanceFrequent to common in the Mountains; fairly common to frequent in most of the Piedmont, but very rare in the western Coastal Plain.
HabitatThis species favors somewhat circumneutral soil, but in a great variety of settings. It favors somewhat dry to mesic forest openings, especially where rocky. It also occurs in glades, barrens, dry thickets, wooded edges, and in meadows.
PhenologyBlooms from May to July, and fruits shortly after flowering.
IdentificationThis is a quite tall species, growing to 4-5 feet tall. It is very similar to, and easily confused with, T. pubescens, which can grow in similar habitats though essentially is found in partly sunny wetlands. Each has mainly bi-ternately divided leaflets (3 groups of 3 leaflets), each leaflet having mainly 3 lobes with the middle the widest, and lobes rounded. In this species, the leaflet undersides have small glands (visible with a hand lens) that might be slightly sticky if the leaflet is squeezed between two fingers; in T. pubescens the leaflet undersides are somewhat pubescent. Both have sessile stem leaves, and both have large and open panicles of small flowers -- male on one individual plant and female on a separate plant. In this species, the filaments on the male flowers droop, like with T. dioicum. However, on T. pubescens the white filaments on the male plants radiate in all directions into a showy ball of white color. The revolute leaflet margins are not overly obvious and not normally used to separate this species from other similar species. T. coriaceum generally has wide leaflets with several teeth on each leaflet lobe, instead of 3 smoothly rounded lobes; and T. macrostylum normally has many leaflets that are entire and unlobed, plus most leaflets are narrower than 1/2-inch wide. Individuals of tall meadow-rues can often be seen on various walks, but normally you must look carefully at the leaves and flower parts to be certain what you have. If in a drier or rockier setting, especially in high pH soils, it should be this species.
Taxonomic CommentsApparently the epithet revolutum is invalid and must be replaced by amphibolum (Weakley 2020).

Other Common Name(s)Waxy Meadow-rue, Skunk Meadow-rue
State RankS4 [S4S5]
Global RankG5
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B.A. SorrieSame data. Female fruits immature. MoorePhoto_natural
B.A. SorriePiedmont, Rascob Road, 23 May 2015. Male flowers. MoorePhoto_natural
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