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Dense-flower Rein Orchid - Piperia elongata
Other Names:
Habenaria elegans var. elata, Piperia elegans var. elata, Platanthera elongata
State Rank Reason (see State Rank above)
DRAFT: Requesting feedback on the 2026 revised rank, factors, and State Rank Reason outlined below and in the Conservation Status Rank Report.
Piperia elongata is uncommon in northwest Montana, where it occurs at the eastern extent of its range. Until recently, the species was believed to be much rarer than what recent observations indicate. Prior to 2020, only a few collections of the species were known from Montana. Since 2020, there have been numerous observations of the species, many of these posted on iNaturalist. Populations occur on a variety of ownerships with the majority occurring on National Forest lands. Population levels are unknown, though are likely small as the plant generally occurs in small numbers or as scattered plants in appropriate habitat. No significant and widespread threats to the species are known. However, localized impacts may occur at some sites from various land uses and activities and from natural events like wildfires, though any impacts are expected to be minor in scope and/or severity. Actual trends are unknown though the species' habitat is largely intact and it is likely to have been relatively stable or experienced only minor declines in the recent past.
Survey and monitoring data are needed to be able to determine population levels, assess condition and for assessing population trends.
General Description
PLANTS: Perennial herbaceous stems, 30-40 mm tall, 1-12 mm in diameter (measured above basal leaves). Roots are tubers, 10-40 mm in length, with several fibrous rootlets. Sources: Douglas et al. 2001; Lesica et al. 2012; and Ackerman and Morgan in Flora of North America (FNA) 2002.
LEAVES: Basal, 2 to 5 in number and prostrate. Leaf shape is oblong, 7–15 cm in length, and 1-8.4 cm in width. Cauline leaves 4-22 in number and bract-like. Sources: Douglas et al. 2001; Lesica et al. 2012; and Ackerman and Morgan in FNA 2002.
INFLORESCENCE: A spike-like raceme of overlapping yellow-greenish flowers, 10–20 cm in length. Bracts 9–14 mm in length. Source: Lesica et al. 2012.
Phenology
Flowers May-September (FNA 2002).
Diagnostic Characteristics
Dense Flower Rein Orchid -
Piperia elongata, SOC
*Inflorescence: Flowers are sparse to dense, tending to overlap yet not be crowded. Flowers do not spiral on the stem.
*Flowers: Petals and sepals are yellow-green to green.
*Lip petal: Has a long, slender spur, weakly curved spur, 6-15 mm long. The spur is more than twice as long as the lip petal.
*Leaves: Prostrate, but not appressed to the ground. Often withering by the time pollination occurs.
Hillside Rein Orchid -
Piperia elegans*Inflorescence: Flowers are crowded. Flowers do not spiral on the stem.
*Flowers: Petals are white with green sepals.
*Lip petal: Has a long, slender spur, weakly curved spur, 8-12 mm long. The spur is more than twice as long as the lip petal.
*Leaves: Prostrate, but not appressed to the ground. Often withering by the time pollination occurs.
Alaska Rein Orchid -
Piperia unalascensis*Inflorescence: Flowers are well-separated. Flowers do not spiral on the stem.
*Flowers: Petals and sepals are yellow-greenish.
*Lip petal: Has a short spur, clavate (club-shaped), 3-5 mm long. The spur is about as long as the lip petal.
*Leaves: Prostrate, but not appressed to the ground. Often withering by the time pollination occurs.
Bog Orchids -
Platanthera species
*Flowers: Arranged in a spike-like raceme, but do not spiral around the stalk.
*Lip petal: Forms a downward pointing spur.
*Leaves: Either near the plant's base (basal) or leafy along entire stem (cauline). If basal than either appressed to the ground or only on the lower stem (lacking upper stem leaves). If cauline then leaves are sheathing, alternately-arranged, and may whither by the time pollination occurs.
Ladies'-tresses -
Spiranthes species
*Flowers: Arranged in a spike and spiral on the stalk to form 3- or 4- ranks/columns.
*Lip petal: Lacks a spur.
*Leaves: Relatively long and narrow. Largest at the base, becoming progressively smaller towards the inflorescence. Leaves usually do not whither by the time pollination occurs.
Species Range
Montana Range
Range Descriptions
Native
Range Comments
Canada: BC; USA: CA, ID, MT, OR, WA (FNA 2002). Known in Montana from one collection in Lincoln County (Lesica 2012).
(Lesica’s contribution from Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
Observations in Montana Natural Heritage Program Database
Number of Observations: 76
(Click on the following maps and charts to see full sized version)
Relative Density
Recency
(Observations spanning multiple months or years are excluded from time charts)
Habitat
Moist to wet meadows; valleys (Lesica 2012); dry, exposed habitats, forest chaparral (FNA 2002), shrubby areas, woods and woods edges, from lowland to montane elevations (Douglas et al. 2001).
(Lesica’s contribution from
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
Ecological Communities Associated with this Species
Forest and Woodland
Montane - Subalpine Forest and Woodland
Reproductive Characteristics
Flowers: Green or yellow-green (Lesica 2012), not scented (Douglas et al. 2001), or if scented, then only faintly at night, sometimes smelling like honey (FNA 2002); sepals 4–6 mm long (Lesica 2012), the upper sepal more or less upright, the lateral sepals somewhat recurved (Douglas et al. 2001); petals sickle-shaped (falcate), 2-5.5 mm long (Douglas et al. 2001); lip petal deltoid-lanceolate, bent back (FNA 2002), 4–6 mm in length; spur weakly curved, 6–15 mm long (Lesica 2012).
Fruit: Capsule ascending to upright (Douglas et al. 2001), 5–10 mm in length (Lesica 2012); seeds brown (FNA 2002).
Stewardship Responsibility
Threats or Limiting Factors
STATE THREAT SCORE REASON
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).
References
- Literature Cited AboveLegend:
View Online Publication
Douglas, G.W., D. Meidinger, and J. Pojar, editors. 2001. The Illustrated Flora of British Columbia. Volume 7. Monocotyledons (Orchidaceae through Zosteraceae). British Columbia Ministry of Environment, Lands and Parks and British Columbia Ministry of Forests, Victoria. iv + 379 pp.- Flora of North America Editorial Committee. 2002. Flora of North America North of Mexico. Vol. 26. Magnoliophyta: Liliidae: Liliales and Orchidales. New York, NY: Oxford Univ. Press. xxvi + 723 pp.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- MTNHP Threat Assessment. 2021. State Threat Score Assignment and Assessment of Reported Threats from 2006 to 2021 for State-listed Vascular Plants. Botany Program, Montana Natural Heritage Program, Helena, Montana.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?- Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
- Web Search Engines for Articles on "Dense-flower Rein Orchid"
