Vascular Plants of North Carolina
Account for Northern Blue Cohosh - Caulophyllum giganteum   (Farwell) Loconte & Blackwell
Members of Caulophyllum with account distribution info or public map:
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Section 6 » Order Ranunculales » Family Berberidaceae
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Author(Farwell) Loconte & Blackwell
DistributionFound mainly in the northern mountains (Ashe and Alleghany counties to Avery County), but also a record for Graham County, in the southwestern mountains. The iNaturalist website has confirmed photos of this species in a number of additional mountain counties; only those for Watauga and Avery seem to be clearly correct, in addition to Ashe and Graham. Further review of these photos by the website editors is needed.

This is a Northern species, ranging from eastern Canada south to PA and OH, and southward mainly in the mountain regions to western NC and central TN.
AbundanceRare in the northern mountains, and extremely rare farther south, with only one record south of the northern tier of counties. Perhaps overlooked, and almost certainly is present in other counties and locations; the editors suggest a State Rank of S1S2 instead of S1 for now. This is a Significantly Rare species.
HabitatThis is a species of rich forests, typically growing in Rich Cove Forests. As C. thalictroides also grows mainly in Rich Cove Forests, it is not clear if there is any habitat separation of the two, where both occur in the same county.
PhenologyBlooms from April to May, generally "about two weeks earlier than C. thalictroides where they grow together" (Weakley 2018). Fruits in July and August.
IdentificationThis species is very similar to C. thalictroides in growth form (see that species for information). It differs mainly in that the flowers are usually brown-purple, instead of light greenish-yellow; the terminal leaflet is larger, about 3 inches long and 2.5 inches wide, as opposed to about 2 inches long and somewhat narrower; and flowering earlier, with the flowers opening before the leaves expand, versus flowers opening as the leaves expand.
Taxonomic CommentsThough Weakley (2018) and NatureServe consider this as a good species, some references do not, and simply call them together as C. thalictroides. Most recent references do split them out.

Other Common Name(s)Giant Blue Cohosh, Early Blue Cohosh
State RankS1 [S1S2]
Global RankG4G5
State StatusSR-P
US Status
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