Listera australis - Southern twadeblade

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Listera australis / Neottia bifolia, Southern twadeblade, is a native perennial herbaceous plant. It is an orchid and blooms April to early May. In New Jersey it is found in the Pine Barrens. It frequently goes unnoticed because the flowers are so small and its coloration causes it to blend in with its habitat

Flowers

The southern twadeblade plant has a single stem with a cluster of 5 to 25 flowers in a terminal raceme (flowers on a stem with short stalks).
The flowers are brownish-red to greenish-purple.

Each flower has a prominent narrow, pointed two-pronged lip (labellum / lower petal) that may reach 10 mm (0.4 inches) in length. Like all orchids, Listera has 3 petals and 3 sepals. The two lateral petals are recurved, folding tightly backwards. The 3 sepals are cupped forward. Listera australis / Neottia bifolia- Southern twadeblade - flower - close up Listera australis / Neottia bifolia- Southern twadeblade -  flower - close up


The major parts of the flower are labeled. The T shaped nectary is clearly seen. One of the sepals is not visible in the photo below. Listera australis / Neottia bifolia- Southern twadeblade - flower parts - labels

This photo shows more clearly the recurved petal. Also seen are the pollinia (yellow) in the column, as well the raised nectar glands on the labellum
Listera australis / Neottia bifolia- Southern twadeblade -  flower  - close up

Photo of back view. The glandular hairs can be seen on the pedicel.Listera australis / Neottia bifolia- Southern twadeblade -  flower  - close up


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Fruit

After the ovary matures, slits open up to expose some of the seeds to the wind, dispersing the seeds over time. Notice that the all the petals and sepals remain intact when the ovary matures.
Listera australis - Southern twadeblade - fruit Listera australis - Southern twadeblade - fruit


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Plant & Habitat

The entire plant is hardly 6 inches tall and the flower cluster gets lost in the habitat and especially in the shade. In New Jersey it grows in the shaded bogs, wet woods, sphagnous areas in the Pine Barrens. The most visible part of the plant are the two sessile leaves that appear about 1/3 up the stem. The two leaves together only measure about 1.5 inches.

Listera australis - Southern twadeblade - Plant Listera australis - Southern twadeblade - Plant Listera australis - Southern twadeblade - leaves



All photos by H & M Ling, flowers 4/28/2017 & 5/5/2018; fruit 5/31/2017; Pine Barrens.

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Additional information

Additional information / references:

NJ : https://www.cumauriceriver.org/botany/Listera_australis.html 

Description: https://guides.nynhp.org/southern-twayblade/  
https://uswildflowers.com/detail.php?SName=Listera%20australis
https://gobotany.nativeplanttrust.org/species/neottia/bifolia/

Conservation: https://www.nativeplanttrust.org/conservation/conservation-research-plans/ 

Legal Status:
https://plants.usda.gov/core/profile?symbol=LIAU3 Distribution and legal status: endangered in 6 states in the eastern US.

In NJ it had a Heritage ranking of S2 (State imperiled in New Jersey because of rarity). It is no longer on the "List of Endangered Plant Species and Plant Species of Concern, June 2016". However, it is still an at risk plant on other lists.

NatureServe ConservationStatus: G4 Apparently Globally Secure—Uncommon but not rare; some cause for long-term concern due to declines or other factors.

 

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