Platanthera leucophaea

Eastern Prairie Fringed Orchid

FWS Focus

Overview

Characteristics
Overview

The eastern prairie fringed orchid is protected under the Endangered Species Act as a threatened species. This orchid is a perennial plant that grows from an underground tuber. Flowering begins from late June to early July, and lasts for 7 to 10 days. Blossoms often rise just above the height of the surrounding grasses and sedges.

The eastern prairie fringed orchid has a a single upright, leafy stem with a vertical flower cluster (flower spike). The flower spike has five to 40 creamy white flowers, and each flower has a three-part fringed lip.

Scientific Name

Platanthera leucophaea
Common Name
eastern prairie fringed orchid
prairie white fringed orchid
FWS Category
Flowering Plants
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Habitat

Characteristics
Habitat

The eastern prairie fringed orchid occurs in a wide variety of habitats, from wet to mesic prairie, to wetland communities, including sedge meadow, fen, marsh and marsh edge.  It can occupy a very wide moisture gradient of prairie and wetland vegetation.  In general, the habitat is moist or moderately moist.  The orchid requires full sun for optimal growth and flowering, which ideally would restrict it to grass and sedge dominated plant communities.  However, in some plant communities where there are encroaching species such as cattail and/or dogwood, the orchid may be interspersed or within the edge zones of these communities and thus can sometimes occur in partially shaded areas.   The substrate of the sites where this orchid occurs include glacial soils, lake plain deposits, muck or peat, which could range from more or less neutral to mildly calcareous (Bowles et al. 2005, USFWS 1999).  In some cases, the species may also occur along ditches or roadways where this type of habitat is present. 

Processes that maintain habitats in early or mid-successional phases may be important in providing the sunny, open conditions required by the orchid (USFWS 1999).  Sedge meadow and marsh habitats that support this orchid are usually early- or mid- successional because of past grazing, drainage, or soil disturbance.  Patch disturbances that expose the soil to this orchid’s seeds, and reduce competition from established plants, may be needed for seedling establishment. 

The mycorrhizae Ceratorhiza must be present within the soil for seed germination to occur.  A symbiotic relationship between the seed and this soil fungus is necessary for seedlings to become established.  The mycorrhizae help the seeds assimilate nutrients in the soil.  Preliminary studies indicate that without this mycorrhiza, germination of this species does not occur.  Current research is exploring the possibility that orchid seeds could be inoculated with this mycorrhiza before sowing in appropriate habitat.

Hawkmoths are the pollinators of this orchid species.  Range wide, three species of hawkmoths are confirmed pollinators of this orchid: Lintneria eremitus (hermit sphinx), Eumorpha pandorus (pandorus sphinx) and Eumorpha achemon (achemon sphinx).  In Illinois only the hawkmoth Lintneria eremitus is a confirmed pollinator, although there may be others.  Host plants for the caterpillars of Lintneria eremitus include various species of beebalm (Monarda spp.), mints (Mentha spp.), bugleweed (Lycopus spp.) and sage (Salvia spp.).  It may be prudent to include populations of these species in the landscape when providing restoration for the orchid. 

 

Wetland
Urban
Rural
Wetland
Urban
Rural
Characteristic category

Life Cycle

Characteristics
Life Cycle

The eastern prairie fringed orchid is protected under the Endangered Species Act as a threatened species. This orchid is a perennial plant that grows from an underground tuber.

 

 

Life Cycle

This orchid is a perennial plant that grows from an underground tuber. Flowering begins from late June to early July and lasts for 7 to 10 days. Blossoms often rise just above the height of the surrounding grasses and sedges.  The more exposed flower clusters are more likely to be visited by the hawkmoth pollinators, though they are also at greater risk of being eaten by deer. Seed capsules mature over the growing season and are dispersed by the wind from late August throughout the fall and winter.

Reproduction

The underground tuber develops a bud and the precursors of a flowering stalk during the growing season the year before flowering.  The leaves and a developing flower cluster begin to emerge above ground in April/May of the following growing season.  Flowering begins from late June to early July, and lasts for 7 to 10 days. Blossoms often rise just above the height of the surrounding grasses and sedges.  The more exposed flower clusters are more likely to be visited by the hawkmoth pollinators, though they are also at greater risk of being eaten by deer.  Three species of hawkmoth are confirmed pollinators: Lintneria eremitus (hermit sphinx), Eumorpha pandorus (pandorus sphinx) and Eumorpha achemon (achemon sphinx). Visiting hawkmoths receive pollen on their proboscises as they ingest nectar from the flower's long nectar spurs. The garden pest tomato and tobacco hornworms have been observed visiting the orchids but are not considered pollinators as none have been observed with this orchid's pollinia on their proboscises. 

Following pollination, the seed capsules mature over the growing season with each seed capsule producing thousands of tiny, lightweight, dust-like seeds which are dispersed by wind after the capsules dry out and crack to release the seeds.

 

Characteristic category

Similar Species

Characteristics
Similar Species

The eastern prairie fringed orchid is similar to the western prairie fringed orchid; however, it inhabits primarily areas east of the Mississippi River.  Both orchids produce flower stalks up to 47 inches tall. Each stalk has up to 40 white flowers about an inch long. The western prairie fringed orchid's flowers are somewhat larger than those of the closely related eastern prairie fringed orchid.

Characteristic category

Physical Characteristics

Characteristics
Size & Shape

This plant is 8 to 40 inches tall and has an upright leafy stem with a flower cluster called an inflorescence. The 3- to 8-inch lance-shaped leaves sheath the stem. Each plant has one single flower spike composed of five to 40 creamy white flowers. Each flower has a three-part fringed lip less than 1 inch long and a nectar spur (tube-like structure structure
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) which is about 1 to 2 inches long.

Geography

Characteristics
Geography

The eastern prairie fringed orchid is protected under the Endangered Species Act as a threatened species. 

 

 

Range

The eastern prairie fringed orchid currently occurs in eight states (Illinois, Indiana, Iowa, Maine, Michigan, Missouri, Ohio, Wisconsin) and possibly one additional state, Virginia, although surveys have not been conducted in Virginia for many years due to landowner refusing access.

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