Loesel's Twayblade - Liparis loeselii
State Rank Reason (see State Rank above)
Known from several occurrences clustered in a small area of the Swan Valley. Susceptible to changes in hydrology. May also be susceptible to impacts from fire.
Loesel's Twayblade is a glabrous, herbaceous perennial with naked stems that are up to 15 cm high arising from a bulb-like base. The two nearly erect, narrowly elliptic basal leaves are 5-15 cm long and have a broad petiole and a thickened midrib. Several flowers are borne on short stalks at the tops of the stem. Each white to greenish flower has 3 narrowly lance-shaped sepals that are 5-7 mm long, 2 nearly linear petals, and a strap-shaped lip petal that is 4-5 mm long and narrowed at the base. The petals and sepals are united together at the top of the curved, club-shaped ovary. The fruit is a narrowly elliptic capsule with numerous dust-like seeds.
Flowering from June-mid-July.
Liparis loeselii might be confused with species of Platanthera, but flowers of the latter have a tubular spur and lack a short stalk. In addition, species of Platanthera that occur in our fens have leafy stems. Species of Listera usually do not occur in fens, and their two leaves are attached to the stem rather than being basal.
BC to QC south to WA, MT, LA and VA (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
Wet, organic soils of calcareous fens in the valley and montane zones.
Ecological Systems Associated with this Species
Threats or Limiting Factors
STATE THREAT SCORE REASON
Reported threats to Montana's populations of Loesel's Twayblade are currently assigned as unknown. Potential threats due to noxious species are negligible according to reported data (MTNHP Threat Assessment 2021).
- Literature Cited AboveLegend: View Online Publication
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.