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Southern Twayblade Listera australis Lindl. |
Monocots |  Printer Friendly Version (PDF) |
Family: Orchid Family (Orchidaceae)
State Protection: Endangered 
listed species are those with: 1) 5 or fewer extant sites, or 2) fewer than 1,000 individuals, or 3) restricted to fewer than 4 U.S.G.S. 7 ? minute topographical maps, or 4) species listed as endangered by U.S. Department of Interior. Federal Protection: Not Listed State Rarity Rank: S1
A State Rarity Rank of S1 means: This plant is endangered/critically imperiled in New York because of extreme rarity (typically 5 or fewer populations or very few remaining individuals) or is extremely vulnerable to extirpation from New York due to biological factors. Global Rarity Rank: G4
A Global Rarity Rank of G4 means: This species is apparently secure globally (typically with more than 100+ populations), though it may be quite rare in parts of its range, especially at the periphery. Did you know? There are four species of Listera in New York and all of them are rare except Listera cordata, the heartleaf twayblade. These orchids are often very hard to see and great care must be taken when searching for them to avoid trampling. The small aboveground stem may not appear every year and when it does it only lasts for a few weeks. The genus name is dedicated to Martin Lister, 1638-1711, a famous English naturalist. |
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| State Ranking Justification | [-] |
There are seven known populations but half of these are relatively small. One large site contains approximately 2000 plants. There are roughly 20 historical populations that should be surveyed. There are undoubtedly more populations still to find.
| Short-term Trends | [-] |
A few populations have disappeared, despite repeated efforts to relocate these. However, a few new populations have been located. These new populations were likely present at these sites for many years, but infrequent surveys failed to locate them. Overall, there has probably been a slight decline in the total number of plants over the past 100 years, but with greater protection to wetlands these declines have likely stabilized.
| Long-term Trends | [-] |
As bogs, fens, and other wetlands were converted to muck farms or otherwise drained, populations were undoubtedly lost. These threats are minimal today. The number of populations that may have been lost after European settlement is impossible to assess, but speculation leads to the belief that there was at least a slight to moderate decline.
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Home | Advanced Search | About Us Animal Guides | Plant Guides | Community Guides © 2004-2012 New York Natural Heritage Program, a partnership between the New York State Department of Environmental Conservation and the State University of New York College of Environmental Science and Forestry Please cite this page as:
New York Natural Heritage Program. 2013. Online Conservation Guide for Listera australis. Available from: http://www.acris.nynhp.org/guide.php?id=9700. Accessed June 18th, 2013. 
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