Veiny Meadow-rue's flowers have no petals. The distinctive "starburst" pattern of its flowers are made by elongated stamens (Gleason and Cronquist 1991).
There are only 5 existing occurrences and 2 historical occurrences (both from Clinton County) in the state. Only two of the verified occurrences are ranked as "good" and have populations of more than 50 plants, and the undisturbed shoreline habitat it favors has been impacted in many areas.
Only two of the the five verified populations have had population trends documented; these populations appear to be stable or increasing.
One of the verified populations has persisted at the site since at least 1965; additional data on long-term trends are lacking.
Invasive species, including purple loosestrife (Lythrum salicaria) threaten some populations. Boat launches and other human activities may also threaten the plants and their Lake Champlain shoreline habitats.
These shoreline sites need to be protected from human activity, including at boat launches.
In New York, Veiny Meadow-rue has been found growing at cobbly shorelines, wet meadows, and calcareous rock outcrops along or near the Lake Champlain shoreline (New York Natural Heritage Program 2008). Rocky or gravelly soil, often along shores (Gleason and Cronquist 1991). Alluvial or rocky river shores, talus (Haines and Vining 1998).
In New York this species is known only from the Lake Champlain valley and shores in Essex and Clinton Counties.
Veiny Meadow-rue is found throughout most of Canada, and in the northern U.S. states from the Pacific Northwest, south along the Rocky Mountains, and east along the northern tier of states to New York, Vermont, and Maine.
Veiny Meadow-rue is a perennial herbaceous species which grows from rhizomes, up to 1 m tall. The leaves are alternate, and twice-divided, and the lobes of the leaflets are deeply cut, with distinct veins, and are at least sparsely glandular on the underside. The lower leaves have petioles, but the one directly below the infloresence is sessile or has only a short (less than 3 cm) petiole. The sepals are inconspicuous, the yellowish-greenish or pinkish flowers instead dominated by the many elongated stamens. The fruit are inward-curving achenes.
Veiny Meadow-rue is best identified when in flower or fruit.
Thalictrum dioicum is similar to Thalictrum venulosum var. confine, but differs by flowering in May (Thalictrum venosum var. confine flowers in June or July), by having its infloresence subtended by a long-petioled leaf, and by its straight achenes.
Veiny Meadow-rue flowers in June and July, and the fruits may persist through September.
The time of year you would expect to find Veiny Meadow-rue vegetative, flowering, and fruiting in New York.
Thalictrum venulosum var. confine (Fern.) Boivin
Flora of North America recognizes Thalictrum venulosum and T. confine as separate species. These two species, along with T. occidentale, are very similar and the NY Flora Atlas treats them as varieties. More research may support recognition as a full species or lumping of all related taxa under T. venulosum.
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Weldy, Troy W. and David Werier. 2005. New York Flora Atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research. University of South Florida]. New York Flora Association, Albany, NY. Available on the web at (http://newyork.plantatlas.usf.edu/).
Information for this guide was last updated on: May 22, 2008
Please cite this page as:
New York Natural Heritage Program. 2021. Online Conservation Guide for Thalictrum venulosum var. confine. Available from: https://guides.nynhp.org/veiny-meadow-rue/. Accessed April 11, 2021.