Linum intercursum Stephen M. Young

Linum intercursum
Stephen M. Young

Class
Dicotyledoneae (Dicots)
Family
Linaceae (Flax Family)
State Protection
Threatened
Listed as Threatened by New York State: likely to become Endangered in the foreseeable future. For animals, taking, importation, transportation, or possession is prohibited, except under license or permit. For plants, removal or damage without the consent of the landowner is prohibited.
Federal Protection
Not Listed
State Conservation Status Rank
S2
Imperiled in New York - Very vulnerable to disappearing from New York due to rarity or other factors; typically 6 to 20 populations or locations in New York, very few individuals, very restricted range, few remaining acres (or miles of stream), and/or steep declines.
Global Conservation Status Rank
G4
Apparently Secure globally - Uncommon in the world but not rare; usually widespread, but may be rare in some parts of its range; possibly some cause for long-term concern due to declines or other factors.

Summary

Did you know?

This beautiful little wildflower was first collected on Nantucket Island in 1899 by Eugene Bicknell and for many years was thought to be Linum floridanum. When he realized it was a distinct species he described it as Linum intercursum (Bicknell 1912). He did not give a reason for the species name (intercursum = running between) but we can surmise that it meant it was a species that had the characters between Linum floridanum and Linum medium. He called it one of the noteworthy plants of the Hempstead Plains on Long Island. It was first collected there in 1904 but remains elusive today and may now be gone from that site.

State Ranking Justification

There are 10 existing populations which are highly threatened. Only 4 populations have more than 100 plants. There are 29 historical occurrences, but most of the habitat is gone.

Short-term Trends

The populations may be declining, as surveys in 2005 failed to find 5 of 6 populations that were known in the 1980s and 1990s. Populations probably fluctuate year-to-year depending upon precipitation, so more surveys need to be done to determine if the plants are actually gone.

Long-term Trends

There has been a substantial decline in populations from historical records and future long-term trends are equally negative.

Conservation and Management

Threats

The biggest threat to this species is the succession of its open habitat to woody species, although a seed bank can maintain the population for some time until disturbance returns. Some populations also occur along trails, right-of-ways, or roads where the open habitat is maintained, but the plants are still threatened by direct disturbance such as exotic species, trampling, improper mowing, herbicide or bicycle use. One site is threatened by development.

Conservation Strategies and Management Practices

This species needs disturbance to reduce competition from woody plants or more aggressive herbaceous plants, but too much direct disturbance to the plants will reduce or eliminate the population. Its habitat could be disturbed in the non-growing season to open it up for seed germination and colonization, but direct disturbance should be prevented during the growing season.

Research Needs

Seed banking studies are needed to determine how long this species can last in its habitat after succession occurs.

Habitat

Habitat

In New York, Linum intercursum is known from a variety of open, sandy habitats, including maritime dunes, grasslands, and shrublands, and pitch pine-scrub oak barrens (New York Natural Heritage Program 2010). Open oak or pine woods and open places on the coastal plain (Gleason and Cronquist 1991). Sandy soil and barrens on the coastal plain (Gleason 1952).

Associated Ecological Communities

  • Maritime dunes (guide)
    A community dominated by grasses and low shrubs that occurs on active and stabilized dunes along the Atlantic coast. The composition and structure of the vegetation is variable depending on stability of the dunes, amounts of sand deposition and erosion, and distance from the ocean.
  • Maritime grassland (guide)
    A grassland community that occurs on rolling outwash plains of the glaciated portion of the Atlantic coastal plain, near the ocean and within the influence of offshore winds and salt spray.
  • Maritime shrubland* (guide)
    A shrubland community that occurs on dry seaside bluffs and headlands that are exposed to offshore winds and salt spray. * probable association but not confirmed.
  • Pitch pine-scrub oak barrens* (guide)
    A shrub-savanna community that occurs on well-drained, sandy soils that have developed on sand dunes, glacial till, and outwash plains. * probable association but not confirmed.
  • Unpaved road/path
    A sparsely vegetated road or pathway of gravel, bare soil, or bedrock outcrop. These roads or pathways are maintained by regular trampling or scraping of the land surface. The substrate consists of the soil or parent material at the site which may be modified by the addition of local organic material (woodchips, logs, etc.) or sand and gravel. Abandoned railroad beds where tracks have been removed are included here. One characteristic plant is path rush.

Associated Species

  • Agalinis acuta
  • Agalinis purpurea (purple agalinis)
  • Agalinis setacea (needle-leaved agalinis)
  • Andropogon virginicus
  • Aronia
  • Baptisia
  • Bartonia
  • Centaurea
  • Comptonia peregrina (sweet-fern)
  • Danthonia spicata (poverty grass)
  • Eurybia spectabilis (showy-aster)
  • Euthamia graminifolia (common flat-topped-goldenrod)
  • Hudsonia tomentosa (beach-heather)
  • Hypericum gentianoides (orange-grass)
  • Lechea maritima
  • Lespedeza
  • Lysimachia terrestris (swamp-candles)
  • Myrica pensylvanica
  • Panicum
  • Pinus rigida (pitch pine)
  • Polygala nuttallii (Nuttall's milkwort)
  • Polygala sanguinea (blood milkwort)
  • Rhynchospora capitellata (brownish beak sedge)
  • Rubus
  • Schizachyrium scoparium
  • Scleria pauciflora (few-flowered nut sedge)
  • Sorghastrum nutans (Indian grass)
  • Xyris

Range

New York State Distribution

This herb is currently known from Suffolk County on Long Island with a few historical records from Nassau County.

Global Distribution

This small herb occurs in the Southeastern US north of Florida, although it is considered rare in North Carolina. It extends north from Maryland to Massachusetts, where it is rare in every state. There is a disjunct population in Indiana.

Identification Comments

General Description

Sandplain wild flax is an upright perennial herb, simple or branched from the base, growing from 20 to 80 cm tall. The leaves are narrowly elliptic to oblanceolate in shape, sessile, 1 to 2.5 cm long, and opposite near the base of the stem but usually becoming alternate higher up. The flowers are borne on slender ascending branches, with pedicels 1 to 4 mm long. The sepals are lance-shaped and pointed, 2 to 3 mm long, and the inner ones have gland-tipped teeth. The petals are yellow and 4 to 7 mm long. The fruit are pointed capsules 2 to 3 mm long and turbinate (top-shaped), breaking into 10 separate carpels with acuminate tips at maturity (Gleason and Cronquist 1991).

Best Life Stage for Proper Identification

Plants with mature fruit are needed for identification.

Similar Species

Linum intercursum most closely resembles L. medium in habit, stature and foliage, but L. medium has carpels which are blunt or rounded at the summit and half to two-thirds as wide as long, and its capsules are subglobose.

Best Time to See

Linum intercursum flowers from July through August, and fruiting stems may be found year round if they are not covered by snow.

  • Flowering
  • Fruiting

The time of year you would expect to find Sandplain Wild Flax flowering and fruiting in New York.

Sandplain Wild Flax Images

Taxonomy

Sandplain Wild Flax
Linum intercursum Bickn.

  • Kingdom Plantae
    • Phylum Anthophyta
      • Class Dicotyledoneae (Dicots)
        • Order Linales
          • Family Linaceae (Flax Family)

Additional Common Names

  • Wild Flax

Additional Resources

Best Identification Reference

Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.

Other References

Bicknell, Eugene P. 1912. The ferns and flowering plants of Nantucket - X. Bulletin of the Torrey Botanical Club 39(9): 415.

Cain, S. A. 1944. Foundations of plant geography. Harper and Brothers, New York. 556 pp.

Gleason, H.A. 1952. The new Britton and Brown illustrated flora of the northeastern United States and adjacent Canada. 3 volumes. Hafner Press, New York. 1732 pp.

Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.

Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.

New York Natural Heritage Program. 2010. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.

New York Natural Heritage Program. 2019. New York Natural Heritage Program Databases. Albany, NY.

Vuilleumier, B.S. 1967. The origin and evolutionary development of heterostyly in the angiosperms. Evolution 21: 210-226.

Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://newyork.plantatlas.usf.edu/, Albany, New York

Links

About This Guide

Information for this guide was last updated on: February 23, 2011

Please cite this page as:
New York Natural Heritage Program. 2019. Online Conservation Guide for Linum intercursum. Available from: https://guides.nynhp.org/sandplain-wild-flax/. Accessed November 21, 2019.

Back to top