Cypripedium arietinum - Ait. f.
Ram's-head Lady's-slipper
Other Common Names: ram's head lady's slipper
Taxonomic Status: Accepted
Related ITIS Name(s): Cypripedium arietinum Ait. f. (TSN 43540)
Unique Identifier: ELEMENT_GLOBAL.2.150310
Element Code: PMORC0Q020
Informal Taxonomy: Plants, Vascular - Flowering Plants - Orchid Family
Image 21773

© Ian Shackleford

 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Monocotyledoneae Orchidales Orchidaceae Cypripedium
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Concept Reference
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Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Cypripedium arietinum
Taxonomic Comments: Some researchers have proposed segregating Cypripedium arietinum in the genus Criosanthes based upon the separate lateral sepals, spurred lip, and staminode that resembles a fertile stamen. However, investigation of genetic variation among five species of Cypripedium by Case (1994) supports the retention of this taxon within the genus Cypripedium (Penskar and Higman 1999).
Conservation Status
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NatureServe Status

Global Status: G3
Global Status Last Reviewed: 26Aug2016
Global Status Last Changed: 14Jan1992
Ranking Methodology Used: Ranked by calculator
Rounded Global Status: G3 - Vulnerable
Reasons: About 300 extant occurrences of this unique orchid are known from throughout its range, which includes northeastern North America and the Great Lakes region west to Manitoba and Saskatchewan. Over 150 additional occurrences are historical; some of these may be relocated with further survey, but some may be extirpated. Most known populations are quite small, although thousands of individuals have been recorded at a number of locations. In a given year, the total reproductive population is very likely more than 10,000, but less than 100,000. Believed to be declining in various parts of its range. Major threats include clear-cutting, suppression of natural disturbance regimes, residential development (particularly on Great Lakes shorelines), and collection. Other less severe or more local threats include hydrological alterations, deer browsing, mining, cattle grazing, impacts from recreational activities, competition from exotic plants, climate change, and the intrinsic threat posed by the small size of most populations.
Nation: United States
National Status: N3
Nation: Canada
National Status: N3N4 (30Jun2016)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Connecticut (SH), Maine (S1), Massachusetts (S1), Michigan (S3), Minnesota (S2), New Hampshire (S1), New York (S2), Vermont (S2), Wisconsin (S2)
Canada Manitoba (S2S3), Nova Scotia (S1), Ontario (S3), Quebec (S3), Saskatchewan (S2)

Other Statuses

NatureServe Global Conservation Status Factors

Range Extent Comments: Known from northeastern North America and the Great Lakes region west to Manitoba and Saskatchewan. Specifically, it occurs from Nova Scotia west through Maine, New Hampshire, Vermont, southern Quebec (also Anticosti Island), New York, western Massachusetts, southern Ontario, Michigan, northeastern Wisconsin, northeastern Minnesota, southern Manitoba, to eastern Saskatchewan. Also historically known from Connecticut. Using GIS tools, range extent was calculated to be approximately 700,000 km2.

Area of Occupancy: 501-12,500 4-km2 grid cells
Area of Occupancy Comments: Estimated based on a 2 x 2 km grid.

Number of Occurrences: 81 to >300
Number of Occurrences Comments: Approximately 300 occurrences are presumed extant rangewide, with Michigan, Minnesota, and Ontario have the highest numbers. An additional 167 historical and 9 extirpated occurrences are known throughout the range. Penskar and Higman (1999) suggest that some "historical" occurrences of this species may prove to be extant: "although some of the older records do not likely persist today, the elusive nature and difficulty of surveying for this species make it difficult to predict persistence by the collection date alone."

Population Size Comments: Rangewide population count data are lacking. The fact that "most populations are small" (i.e. small colonies or few individuals) is frequently noted even in jurisdictions in the core of the range (e.g. Wisconsin, C. Anderson pers. comm. 2008). Nevertheless, populations in the thousands have been recorded in a number of locations; for example, in Michigan, the species "reaches its peak abundance, sometimes numbering in the thousands, in conifer uplands of northern Michigan" (Penskar and Higman 1999), and "on Isle Royale on Lake Superior, the boreal forest supports an estimated 10,000 individuals" (Judziewicz 2000 pers. comm. cited in Brzeskiewicz 2000). About 6000 individuals are known in Quebec, with 2 occurrences over 1000 individuals, although 16 have less thant 100 individuals (J. Labrecque pers. comm. 2008). In Nova Scotia, a recent status report estimated a total population size of 1344+ individuals in that province (Blaney and Mazerolle 2007), while Vermont is estimated to support up to 1000 individuals (R. Popp pers. comm. 2008). In Massachusetts, the population count is typically under 50, and in New York there are three sites with ~100 plants and the others have less than 25. The percentage of the population that reproduces in a given year is highly variable; for example, % of individuals flowering was observed to range from 22-44% in several Wisconsin populations during a single year (Penskar and Higman 1999). Overall, available data seem to suggest that the reproductive population in any given year is likely 10,000 - 100,000 individuals, although the total population of reproductive + vegetative individuals may be above 100,000.

Number of Occurrences with Good Viability/Integrity: Many (41-125)
Viability/Integrity Comments: 189 of the presumed extant occurrences have been ranked for viability. Of these approximately 47 are believed to have excellent or good viability, with a further 16 having either good or fair viability. Long-term population viability may be difficult to predict for this species, however, as some researchers (e.g. Case 1994) have noted that colonies may persist for years then become less vital or disappear altogether.

Overall Threat Impact: Very high - high
Overall Threat Impact Comments: Major threats include clear-cutting, suppression of natural disturbance regimes, residential development, and collection. Clear-cutting and heavy thinning open up the forest canopy causing more sunlight to reach the ground and dry the soil, problematic since this species apparently requires at least partial canopy cover. Plants can also be mechanically damaged or up-rooted by machinery and disking of the ground after tree removal can cause major impacts. Major soil disturbances are undesirable due to the dependence of this species on mycorrhizal fungi. It should be noted, however, that too much shade is also a frequently-cited threat. This species prefers moderate canopy cover such as that found in mid-successional forest formed from old disturbance such as wind throw or possibly fire. Where such disturbances have been suppressed, active management to partially thin the canopy may be necessary for population persistence, taking care to ensure that subsequent undergrowth is does not overgrow the plants. Residential development is also a significant threat in portions of the species' range, particularly along the shores of the Great Lakes. Development has been cited as a major threat in at least Quebec, Michigan, Minnesota, and Wisconsin. Collection has also been a major threat, as the rarity and unique appearance of this species make it highly sought-after for gardens and collections. In the past, this problem has been greatly exacerbated by the difficulty of propagating the species ex situ, but research on propagation techniques is ongoing and there is hope that it will eventually reduce collection pressure significantly.

Numerous more minor or localized threats have also been noted.Hydrological alterations have been cited as a threat where this species inhabits wetland sites. For example, in Wisconsin, two sites were largely destroyed by drainage and/or construction of impoundments, and in Maine, one site is thought to be declining due to hydrological changes associated with a nearby gravel mine. Browsing by white tail deer is also a significant issue in some areas, such as Massachusetts. Plants that become damaged by herbivores frequently do not appear above ground the following year.Mining operations pose a threat to some populations in Minnesota, and gypsum mining is a demonstrated threat to sites in Nova Scotia. Cattle grazing has also been cited as an impact on populations in Minnesota and Nova Scotia. Impacts from recreational activities, such as trails and access roads through populations and all terrain vehicle traffic have also been cited as threats in some areas. Soil compaction can reduce this species' ability to reproduce vegetatively. Competition from exotic plants, such as Carex flacca in Nova Scotia and buckthorn (Rhamnus cathartica and frangula), Asian honeysuckle (Lonicera morowii and others) and Japanese barberry (Berberis thunbergii) in pine and cedar forests, has also been mentioned as a potential threat. Climate change may have a large impact on this species due to habitat loss or alteration, and some populations considered intrinsically threatened due to very small population size.Finally, this species also appears to contain very low levels of genetic variation (Bornbush et al. 1994, Case 1994). However, Bornbush et al. (1994) note that low variation between populations, in addition to low variation for the species as a whole, suggests that the populations may have been genetically depauperate throughout much of their existence prior to human disturbance. For this reason, they argue that other threats may exert a greater influence on C. arietinum persistence than its relative lack of genetic variation.

Short-term Trend: Decline of 10-30%
Short-term Trend Comments: Overall, potential habitat and extant populations continue to decline due primarily to development pressure, logging practices and suppression of natural disturbance regimes (e.g. fire). In Massachusetts, one current population has declined in size since its discovery, but current management may eventually stabilize it (J. Garrett pers. comm. 2008). In Nova Scotia, numbers at known sites seem relatively stable at present, but the development of large gypsum mines over the past three generations (45-75 years) is estimated to have reduced populations by 59% (Blaney and Mazerolle 2007). In Quebec, there is an overall estimated decline of of 10-30%, principally in the regions of Montréal and Montérégie (J. Labrecque pers. comm. 2008). At the Ridges Sanctuary in Wisconsin, the population was once estimated at over 1000 plants; this population subsequently declined to 150 plants, and only 1 plant was seen in 1992 (C. Anderson pers. comm. 2008); over-shading (due to lack of natural disturbance and/or targeted canopy thinning management) is a possible cause of this decline (Case 1999, pers. comm. cited in Brzeskiewicz 2000). Of the monitoring efforts reported by Brzeskiewicz (2000), one monitored population in each of Maine, Minnesota, and Michigan seems to be thriving, but the number of flowering individuals in a second monitored Michigan population seemed to be declining.

Long-term Trend:  
Long-term Trend Comments: In Massachusetts, at least one population is known to have been lost within the past 30 years due to collection/picking (J. Garrett pers. comm. 2008); this may be the case elsewhere in the range as well. Overall, however, long term trend is difficult to estimate.

Other NatureServe Conservation Status Information

Distribution
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Global Range: Known from northeastern North America and the Great Lakes region west to Manitoba and Saskatchewan. Specifically, it occurs from Nova Scotia west through Maine, New Hampshire, Vermont, southern Quebec (also Anticosti Island), New York, western Massachusetts, southern Ontario, Michigan, northeastern Wisconsin, northeastern Minnesota, southern Manitoba, to eastern Saskatchewan. Also historically known from Connecticut. Using GIS tools, range extent was calculated to be approximately 700,000 km2.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map

U.S. & Canada State/Province Distribution
United States CT, MA, ME, MI, MN, NH, NY, VT, WI
Canada MB, NS, ON, QC, SK

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
MA Berkshire (25003), Franklin (25011), Hampden (25013)*, Hampshire (25015)*
ME Androscoggin (23001), Aroostook (23003)*, Cumberland (23005)*, Hancock (23009)*, Kennebec (23011), Oxford (23017), Penobscot (23019)*, Somerset (23025), York (23031)*
MI Alcona (26001), Alger (26003), Alpena (26007), Antrim (26009)*, Benzie (26019), Charlevoix (26029), Cheboygan (26031), Chippewa (26033), Delta (26041), Emmet (26047), Grand Traverse (26055)*, Gratiot (26057)*, Iosco (26069), Isabella (26073)*, Keweenaw (26083), Leelanau (26089), Livingston (26093)*, Mackinac (26097), Marquette (26103)*, Mason (26105), Menominee (26109), Midland (26111)*, Montmorency (26119), Ontonagon (26131), Oscoda (26135), Otsego (26137), Presque Isle (26141), Roscommon (26143)*, Washtenaw (26161)*
MN Aitkin (27001), Anoka (27003), Becker (27005), Beltrami (27007), Carlton (27017), Carver (27019)*, Cass (27021), Clearwater (27029), Cook (27031), Hennepin (27053)*, Hubbard (27057), Isanti (27059)*, Itasca (27061), Koochiching (27071), Lake (27075), Lake of the Woods (27077), Polk (27119), Roseau (27135), St. Louis (27137), Stearns (27145)*, Wadena (27159), Wright (27171)*
NH Belknap (33001), Carroll (33003), Coos (33007)*, Grafton (33009)*, Hillsborough (33011)*, Merrimack (33013)*, Strafford (33017)*, Sullivan (33019)*
NY Albany (36001)*, Clinton (36019), Essex (36031), Fulton (36035)*, Herkimer (36043), Jefferson (36045), Lewis (36049), Madison (36053)*, Oneida (36065)*, Onondaga (36067)*, Oswego (36075)*, Otsego (36077)*, Warren (36113)*, Washington (36115)*
VT Addison (50001), Bennington (50003)*, Caledonia (50005), Chittenden (50007), Orange (50017), Orleans (50019), Rutland (50021), Washington (50023)
WI Ashland (55003), Calumet (55015)*, Door (55029), Douglas (55031), Florence (55037), Fond Du Lac (55039)*, Manitowoc (55071)*, Marinette (55075), Milwaukee (55079)*, Oconto (55083), Outagamie (55087)*, Ozaukee (55089), Sawyer (55113), Sheboygan (55117)*, Vilas (55125), Waukesha (55133)*, Waupaca (55135)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
01 Upper St. John (01010001)+*, Meduxnekeag (01010005)+*, Lower Penobscot (01020005)+*, Upper Kennebec (01030001)+, Lower Kennebec (01030003)+, Lower Androscoggin (01040002)+, Presumpscot (01060001)+*, Saco (01060002)+*, Piscataqua-Salmon Falls (01060003)+*, Pemigewasset (01070001)+*, Merrimack (01070002)+, Nashua (01070004)+*, Merrimack (01070006)+*, Passumpsic (01080102)+, Waits (01080103)+, Upper Connecticut-Mascoma (01080104)+, Black-Ottauquechee (01080106)+*, Middle Connecticut (01080201)+, Chicopee (01080204)+*, Lower Connecticut (01080205)+*, Housatonic (01100005)+*
02 Upper Hudson (02020001)+*, Hudson-Hoosic (02020003)+, Mohawk (02020004)+*, Middle Hudson (02020006)+*, Upper Susquehanna (02050101)+, Chenango (02050102)+*
04 St. Louis (04010201)+, Beartrap-Nemadji (04010301)+, Bad-Montreal (04010302)+, Ontonagon (04020102)+, Keweenaw Peninsula (04020103)+, Dead-Kelsey (04020105)+*, Betsy-Chocolay (04020201)+, Lake Superior (04020300)+, Manitowoc-Sheboygan (04030101)+*, Door-Kewaunee (04030102)+, Oconto (04030104)+, Peshtigo (04030105)+, Menominee (04030108)+, Tacoosh-Whitefish (04030111)+, Fishdam-Sturgeon (04030112)+*, Wolf (04030202)+, Lower Fox (04030204)+*, Milwaukee (04040003)+, Pere Marquette-White (04060101)+, Muskegon (04060102)+*, Betsie-Platte (04060104)+, Boardman-Charlevoix (04060105)+, Brevoort-Millecoquins (04060107)+, Lake Michigan (04060200)+, St. Marys (04070001)+, Carp-Pine (04070002)+, Lone Lake-Ocqueoc (04070003)+, Cheboygan (04070004)+, Black (04070005)+, Thunder Bay (04070006)+, Au Sable (04070007)+, Tittabawassee (04080201)+*, Pine (04080202)+*, Lake Huron (04080300)+, Huron (04090005)+*, Salmon-Sandy (04140102)+, Oneida (04140202)+*, Chaumont-Perch (04150102)+, Indian (04150303)+, Mettawee River (04150401)+, Otter Creek (04150402)+, Winooski River (04150403)+, Ausable River (04150404)+, Lamoille River (04150405)+, Saranac River (04150406)+*, Lake Champlain (04150408)+, St. Francois River (04150500)+
07 Mississippi Headwaters (07010101)+, Leech Lake (07010102)+, Prairie-Willow (07010103)+, Crow Wing (07010106)+, Platte-Spunk (07010201)+*, Clearwater-Elk (07010203)+*, Crow (07010204)+*, Twin Cities (07010206)+*, Rum (07010207)+, Lower Minnesota (07020012)+*, Upper Chippewa (07050001)+, Flambeau (07050002)+
09 Otter Tail (09020103)+*, Red Lakes (09020302)+, Clearwater (09020305)+, Roseau (09020314)+, Rainy Headwaters (09030001)+, Vermilion (09030002)+, Rainy Lake (09030003)+, Little Fork (09030005)+, Big Fork (09030006)+, Rapid (09030007)+, Lake of the Woods (09030009)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: An orchid 4 to 16 inches tall on a slender stem, having 3 to 5 lance- to ellipse-shaped leaves, often folded, about 2 to 4 inches long. Flowers grow singly, the lowest petal forming a lip in the distinctive conical "ram's head" shape, about an inch or less in length. The lip is white with red or purplish markings in a net-like design.
General Description: A perennial orchid highly variable in height, 7 to 30 cm, with 3-5 bluish green, lance- to ellipse-shaped leaves emerging along the stem in a spiral arrangement. It has a small, terminal flower, with a pouched lower lip. The leaves are often folded lenthwise. The purple to brownish sepals are streaked with green. The petals are similar but undulate (wavy). The approximately 1.5-2.5 cm long, conical pouch of the lip (shaped like a ram's head) is marked with purple, crimson, or even green reticulate (net-like) veination and the mouth is densly long hairy (Penskar and Higman 1999).
Technical Description: Case (1964) described the ram's-head lady's-slipper as follows: "Plant small, inconspicuously glandular-pubescent, 0.7-3 dm tall. Leaves 3-5; where many, lowermost and uppermost often reduced in size; elliptic-lanceolate, noticeably bluish-green, spiraled around stem, not 2-ranked as in our other Cypripediums. Floral bract ovate-lanceolate, acute, 3-5 cm long, 1-1.5 cm wide. Flower solitary or rarely 2; lateral sepals free entirely to base, madder-purple or brownish, green-streaked, 1-2 cm long, 2-5 mm wide, linear. Upper sepal lanceovate, subacuminate, concave. Petals much like sepals in all respects, undulate. Lip saccate, floor prolonged downward into a conical pouch. Mouth of sac rather densely long-pubescent. Base color of pouch white, netted and reticulated with madder-purple, crimson, or sometimes with some green. General aspect of lip color white above, madder below. Lip pouch about 1.5-2.5 cm long, 1-2 cm wide; but overall size of plant and all parts vary considerably with type of habitat; those of wet soils usually much larger. Staminode suborbicular and concave. Seed capsule linear-ellipsoid, distinctly less erect when ripe than that of most Lady's-slippers."
Diagnostic Characteristics: In flower, Cypripedium arietinum is quite distinctive, usually rendering identification straightforward. It could possibly be confused with other pinkish Cypripedium species such as C. acaule and C. reginae. It is easily separated from all other Cypripedium by having three separate sepals rather than two. In addition, its leaves spiraled around the stem distinguish it from C. acaule, which has only basal leaves. Its lower lip whitish strongly veined with red and drawn out into a point distinguishes it from C. reginae, which does not have a lower lip drawn out into a point; also, C. arietinum (7-30 cm) is smaller than C. reginae (25-90 cm).
Ecology Comments: Largely, the ram's-head lady's-slipper appears to reproduce asexually, via offshoots from parental plants (Brower 1977). The flowers appear in late May and early June and last only a short time. Within a given population, the percentage of flowering plants within a population may vary greatly. Bender (1989, 1988, 1987) found that, in Wisconsin, flowering occurred in 22% to 44% of the entire population.

As an attractant to potential pollinators, a light sweet odor is produced by the lateral petals and sepals and labellum (Stoutamire 1967). The labellum plays a greater role in odor production in C. arietinum than any other local species within the genera (Stoutamire 1967). Known pollinators of C. arietinum are small bees, including species in the Dialictus (Halictidae) (Stoutamire 1967) and Megachile (Megachilidae) genera (van der Pijl and Dodson 1966). Apparently mosquitoes are not attracted to the scent given off by the ram's-head and play no role in pollination (Stoutamire 1967). As soon as the flower is fertilized, the over-arching sepal lowers to close the orifice and exclude the entrance of additional insects. Minute seeds produced by the plants are probably not dispersed a great distance from the parental plants, as most populations occur in habitats dense with vegetation (Brower 1977). Stoutamire (1964) stated that seed capsules from this species are often observed on the plant well into the spring of the following year, which may be another agent in hindering the dispersal of seeds over large distances.

Plant size is not a reliable indicator of age or maturity within this species (Bender 1989). In a study of C. arietinum in Wisconsin, Bender tracked individual plants over three years. Results showed that plants do not reach a "mature size" and flower every year. Instead, plants frequently flower one year and remain vegetative the next. Bender (1989) has shown that individual plants will flower only upon reaching a minimum size of 11 cm in height. While plants smaller than 11 cm regardless of age, do not flower, all plants taller than that height were observed to flower. Plants that become damaged by herbivores (both insect and mammal) frequently do not appear above ground the following year (Bender 1989, 1988, 1987).

Palustrine Habitat(s): Bog/fen, FORESTED WETLAND
Terrestrial Habitat(s): Forest - Conifer, Forest - Mixed, Forest Edge, Forest/Woodland, Sand/dune, Woodland - Conifer, Woodland - Mixed
Habitat Comments: Seems to occur in three general situations (Brzeskiewicz 2000): (1) Cool, dense white cedar/balsam/spruce swamps (Thuja occidentalis/Abies balsamea/Picea mariana). (2) Nearly pure sand over limestone beach cobble or bedrock, mulched with juniper (Juniperis communis and J. horizontalis), jack pine (Pinus banksiana), red pine (Pinus resinosa) or white cedar needles, typically on north facing slopes or on low dunes of the upper Great Lakes. Can be especially abundant in the partially shaded shelter of the last fringe of trees before the open beach. (3) Mesic soil of sandy loam or clay under the partial shade of conifer or mixed forest,often including some of the following tree species: upland white cedar, maple (Acer spp.), aspen (Populus spp.), birch (Betula spp.), oak (Quercus spp.) balsam, hemlock (Tsuga canadensis) or pine (Pinus) spp. Prefers cool, sub-acid or neutral soil, but can occur in both mineral-rich and mineral-poor sites, with soils of clay, loam or sand in upland sites and nutrient-poor peat in lowland sites. A relatively common feature of occupied sites is an open, uncrowded understory with low competition from other plants. Occurs in areas with forest cover ranging from 30% to 80%; seems to prefer a moderately open canopy, with both full exposure and complete shade being sub-optimal (Blaney and Mazerolle 2007). 0 - 400 m.

In Michigan, appesrs to thrive best on low Great Lake shore dunes in partial shade of conifers, but also occurring inland under jack pine and oak, and in dense balsam-white cedar-black spruce swamps and bogs. In all cases, cool temperatures appear to be important and populations are often confined to northern exposures or cold air channels. Along Lake Huron, grows beneath juniper and cedar trees under the last fringe of trees before the open lake beaches. At Sleeping Bear Dunes National Lakeshore, occurs on the border between coastal forest and dune communities, where the canopy is composed primarily of balsam fir, white cedar, red pine, white pine, and aspen. In Isle Royale National Park, grows in boreal forest clearings. Co-occurring tree species in old dune habitats along the Great Lakes include Thuja occidentalis, Abies balsamifera, Picea glauca, Pinus banksiana, Betula papyrifera, and Tsuga canadensis; in the understory of jack pine "pocket forests" of the Grand Sable Dunes, associated tree species include Pinus banksiana, Betula alleghaniensis, Fagus grandifolia, Ostrya virginiana, Acer pensylvanicaum, Acer saccharum and Abies balsamea. At dry inland forest/woodland sites, co-occurring trees include Pinus strobus, Pinus resinosa, Pinus banksiana, and Populus tremuloides. In coniferous swamps, dominant trees include cedar, tamarack, spruce, and fir. Although the species usually attains its largest physical size in swamps or bogs, it reaches its peak abundance in conifer uplands of northern Michigan. In Minnesota, the species occurs on hummocks of Sphagnum moss in forested sites of Sphagnum bogs and swamps (typically dominated by Thuja occidentalis, Larix laricina and Picea mariana) or dry sand forests (typically dominated by Pinus resinosa, Pinus banksiana, and Pinus strobus). Seems to be found most often in the transition zone between upland forest and lowland conifer. In Saskatchewan, grows under jack pine with an open under-story with reindeer lichen and bearberry. In Wisconsin, occupies three distinct habitats: sandy jack pine (Pinus banksiana) woods with little or no understory vegetation (also sometimes in white pine woods with other conifers); white cedar (Thuja occidentalis) woods (sometimes with Picea glauca, Abies balsamifera, and northern hardwoods), sometimes on stabilized dunes, over limestone and dolomite along the shore of Lake Michigan in Door County; and white cedar (Thuja occidentalis) bogs and tamarack (Larix laricina) swamps. In the more eastern part of its range, in Quebec, the species inhabits rocky slopes, mixed and conifer forests and woodlands. It is rarely found more than 30 meters from the reach of water. Several northern records, near Lake Superior, are from moist to wet clay banks under Thuja occidentalis or red pine. Associated canopy species on the clay banks include big tooth aspen, red maple, and white spruce.. In New Hampshire occurs primarily in cool, partially to fully shaded areas in acidic soils. Habitats include wet Thuja occidentalis woods; mesic, wooded hillsides under pines and hemlocks or red oak, white pine, hemlock, moosewood and witch hazel; and well-drained, ledgy slopes under deciduous trees. In Maine, occurs in acidic mixed hardwood/conifer forests open stands of northern white cedar, or sometimes nearly pure stands of hemlock, growing in moist, sandy or loose soil sites in well drained situations in partial shade, at relatively low elevations. Also can be found in well-drained Larix bogs, and Thuja swamps,and one site is on a hillside in a hardwood stand with very rich soil. In Vermont, can occur in mesic,limey hardwood forest red pine forest, limestone cedar bluff and cedar or hardwood-cedar swamps. This can include second-growth (formerly pasture) woods dominated by pine and hardwoods (Pinus strobus, Acer saccharum, Fraxinus americana, Fagus grandifolia); but more typically it occurs in association with northern white cedar (Thuja occidentalis) either in cedar or mixed hardwood-cedar swamps or on dry limestone bluffs overlooking Lake Champlain. It also occurs in association with hemlock and red pine either on lake bluffs or in red pine forest In Massachusetts, found in seasonally moist woods of red oak, white oak, hemlock, sugar maple, white ash and black birch. In New York, found on hummocks in calcareous swamp-forests, in open coniferous or mixed forests, and in scrub over limestone. In Nova Scotia,it is largely associated with gypsum bedrock and is found in moderately open, mesic woods on outcrops, cliff tops, river banks, moderate to steep slopes and in sinkholes. Forest cover at these sites includes deciduous-dominated, conifer-dominated and mixed stands of young-intermediate to mature forest.

In Minnesota, associates in Sphagnum bogs and swamps include Cornus canadensis, Ranunculus laponicus, Rubus acaulis, Platanthera obtusata, Sarracenia purpurea, Orchis rotundifolia, Smilacina trifolia and Cypripedium acaule, while associates in dry sand forests including Lithospermum canescens, Gaultheria sp., Vaccinium angustifolium, Arctostaphylos uva-ursi, Cypripedium acaule and lichens. In Michigan, additional associates in old dune habitats along the Great Lakes include Arctostaphylos uva-ursi, Prunus virginiana, Iris lacustris, Polygala paucifolia, and Aster sp. Additional associates at dry inland sites include Pyrola spp., Cladonia spp., Pteridium spp., Cypripedium acaule, C. calceolus, Goodyera spp., Corallorhiza spp., Chimaphila umbellata, Epigaea repens, Fragaria spp., Maianthemum canadense, Rhus radicans, Vaccinium spp., Linnea borealis and Calypso bulbosa. Common associates within the jack pine stands on drier sites include Andropogon scoparius, Arctostaphylos uva-ursi, Lithospermum caroliniense, Shepherdia canadensis and Zigadenus glaucus. In moister, more dense stands of jack pine, Carex eburnea, Chimaphila umbellata, Corallorhiza striata, Cypripedium acaule, Goodyera oblongifolia, Linnaea borealis and Pyrola secunda are common associates. Associates in bog habitats include Habenaria dilatata, Platanthera flava var. herbiola, Arethusa bulbosa, Spiranthes romanzoffiana, Pyrola rotundifolia, Utricularia intermedia, Gentiana andrewsii, Polygonum amphibium, Polygala paucifolia and Potentilla palustris. In Wisconsin, additional associates include Aster macrophyllus (in Thuja occidentalis forest), Cypripedium acaule (in tamarack swamp), and Aster macrophyllus, Iris lacustris and Primula mistassinica (in Thuja occidentalis-Picea glauca-Abies balsamifera forest/woodland). In Maine, associates in mixed hardwood/conifer forests include Trientalis borealis, Uvularia sessilifolia, Uvularia grandiflora, Linnaea borealis, Cornus canadensis, Pyrola sp., and ferns; associates in Larix and cedar bogs include Sarracenia purpurea and shrubby heaths. In Vermont, associated with Ranunculus acris, Erigeron philadelphica and Oxalis europea in second-growth woods and with Ceanothus americanum, Waldsteinia sp., Maianthemum canadense and Taraxacum officinale at sites dominated by Thuja sp., Abies balsamea, and Acer saccharum.

Economic Attributes
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Economically Important Genus: Y
Management Summary
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Stewardship Overview: Canopy cover may need to be carefully managed at some sites, as most sources agree that this species prefers a moderately open canopy (30-80% cover). Sites should therefore be protected from clear-cutting or intensive selective harvesting where possible (to maintain at least 30% cover). In addition, where natural disturbance regimes are not fully functional and canopy cover exceeds historic levels, some partial canopy thinning may be beneficial (to keep cover under 80%). However, when thinning the canopy, subsequent growth of the understory should be carefully monitored to make sure it does not overgrow the plants. Re-routing of trails may also be beneficial where recreational impacts are apparent. In addition, enforcement and educational strategies that could help minimize illegal collection should be considered (Penskar and Higman 1999).
Restoration Potential: The recovery potential of this species is largely unknown at this time. The species has not been successfully propagated from seed, and transplantation is largely unsuccessful.
Preserve Selection & Design Considerations:

Land protection for this species is dependant on the type of habitat that is occupied by the species. In all habitats, protection of the immediate population plus sufficient buffer is necessary. In bogs, land protection must include the entire system in which the species occurs. Ditching and other destructive actions within any portion of the bog system can have major impacts on water tables and, consequently, C. arietinum. Jack pine forest habitats must be protected by clear-cut logging practices with sufficient buffer to guarantee protection of prime habitat conditions. Sandy, old dune habitats, similarly should provide protection from logging. Extensive habitats provide the best possibilities of long-term survival and such areas should be designated as of the highest priority for protection.

Management Requirements:

Brackley (pers. comm.) stated that one population in New Hampshire needs to have the habitat manipulated so that more sunlight reaches the forest floor. Thompson (pers. comm.) stated that although it appears that the species prefers successional habitats, it is not known how to manage for the species, or whether active management would actually benefit the species. It is known that clear-cutting of forests is deadly to the species. Bender (pers. comm.) has been experimenting with partial canopy removal at a site in Wisconsin.

Ewert (pers. comm.) suggested that foot traffic should be eliminated from the vicinity of known colonies and that no development should take place.

Thinning of tree canopies might be considered at sites that are, through natural succession, becoming too closed. Excessive thinning or logging can have detrimental effects on C. arietinum populations by overexposing and drying out habitats and individual plants. It is too early to know how on-going artificial thinning programs are working at The Ridges Sanctuary in Wisconsin. If research suggests that artificial thinning of canopies is having a beneficial impact on populations of this species, such procedures should be implemented in shaded habitats. Clear-cut logging practices should be replaced by selective logging in areas containing populations of C. arietinum.

Monitoring Requirements: Monitoring programs should be directed at assessing the population stability over time, determining the longevity of individual plants as well as determining the conditions favorable for seed germination and establishment (Ewert pers. comm.).

Pollinator availability should also be monitored at extant sites. Although populations may be able to expand at any given site through vegetative reproduction, long-term success of the species may depend partially on the abundance of potential pollinators. Without such pollinators, gene flow between populations and establishment of new populations through seed production may not occur.

Thompson (pers. comm.) suggested that monitoring of populations in successional habitats be conducted in order to determine whether succession is a threat and whether management would be helpful.

See Bender (1987-1990) for specific methodologies that have been used for the species in Wisconsin. Populations and individual plants have been tracked over time through permanent plots in order to learn more about the life-history of the species. Canopy photos have also been taken in order to provide information on how C. arietinum responds to varying levels of light.

Observations of potential pollinators should be made at C. arietinum population over a set span of time, with a series of observations made during different portions of the day (morning, afternoon, evening). Meteorological notes should be made at each observation period to reflect conditions that may alter foraging behavior.


Management Programs:

The Pictured Rocks National Lakeshore is working to control visitor access to C. arietinum populations. Largely, current management is to let natural events run their course. Contact: Walter Loope, Pictured Rocks National Lakeshore. Telephone No. (906) 387-2607.

Monitoring Programs:

The Massachusetts Natural Heritage Program is currently monitoring the state's sole extant population on an annual basis, noting the percent of the individuals flowering, fruiting or in a vegetative state (Sorrie pers. comm.). The general location of individuals and changes in habitat (if any) are also noted. Contact: Bruce Sorrie, Massachusetts Natural Heritage and Endangered Species Program, Division of Fisheries and Wildlife, 100 Cambridge St., Boston, MA 02202. Telephone No. (617) 727-9194.

The Michigan Chapter of The Nature Conservancy conducts casual counts of this species at its Grass Bay Preserve (Ewert pers. comm.). Outside of that, no monitoring is done. Contact: Dave Ewert, Michigan Land Steward, Michigan Field Office, The Nature Conservancy, 2840 E. Grand River, Suite 5, East Lansing, MI 44823. Telephone No. (517) 332-1741. The species is apparently locally common in Michigan, so not much emphasis has been placed on monitoring in that state (Penskar pers. comm.).

Joyce Bender of the Kentucky Natural Heritage Program is in the midst of an annual monitoring project at The Ridges Sanctuary in Bailey's Harbor, Wisconsin. Begun in the summer of 1986, four years of data have been obtained relative to the life history of the species at this site. Permanent plots have been established at 4 sites, with canopy cover photographed as part of a canopy thinning study. In addition, populations were assessed throughout The Ridges Sanctuary. Contact: Joyce Bender, Kentucky Natural Heritage Program, Kentucky Nature Preserves commission, 407 Broadway, Frankfort, KY 40601. Telephone No. (502) 564-2886.

Welby Smith of the Minnesota Natural Heritage Program is currently conducting a monitoring program on a population in Minnesota. He has been able to acquire information pertinent to the life history of the species since 1983, when the annual monitoring program began. Contact: Welby Smith, Minnesota Natural Heritage Program, Department of Natural Resources, 500 Lafayette Rd., St. Paul, MN 55155. Telephone No. (612) 297-3733.

Susan Hayward has been conducting an annual monitoring program for C. arietinum at two sites in Maine, one owned by The Nature Conservancy and the other by the New England Wildflower Society. The New England Wildflower Society population occurs in a bog, while The Nature Conservancy population occurs in dry, deciduous woodlands. Monitoring began in 1988, with methodologies very similar to that of Bender (1989, 1988, 1987). Individual plants are followed through time in some subplots, while the number of stems, number of leaves per stem, height, presence of flowers and fall fruit are also noted. Contact: Susan Hayward, 107 Nichols St., Lewiston, ME 04240. Telephone No. (207) 782-5238.

The Pictured Rocks National Lakeshore in Michigan is currently monitoring populations of C. arietinum within the Grand Sable Dunes unit. A number of permanent plots were installed in 1988 by Janet Schultz to monitor population changes over time. Populations are expected to be monitored again this coming year (1990). Contact: Walter Loope, National Park Service, Pictured Rocks National Lakeshore, P.O. Box 40, Munising, MI 49862-0040. Telephone No. (906) 387-2607.

Management Research Programs: Welby Smith of the Minnesota Natural Heritage Program is currently monitoring populations in Minnesota in order to learn more about the species' life history and habitat needs. Contact: Welby Smith, Minnesota Natural Heritage Program, DNR, 500 Lafayette Road, St. Paul, MN 55155. Telephone No. (612) 297-3733.

Pictured Rocks National Lakeshore is currently investigating the dynamic dune processes of the Lake Michigan shoreline. Information obtained from this study will have direct management implications for C. arietinum populations. Contact: Walter Loope, Pictured Rocks National Lakeshore, P.O. Box 40, Munising, MI 49862-0040. Telephone No. (906) 387-2607.

Population/Occurrence Delineation
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Minimum Criteria for an Occurrence: An Element Occurrence for Cypripedium arietinum is any natural population of one or more plants and the habitat on which the plant(s) is/are present. There is no good evidence demonstrating rhizome dormancy in this taxon despite the fact that it is frequently cited (Case pers. comm. 1997). Anecdotal accounts of subterranean dormancy may be attributable to the production of fewer buds off of rhizomes and therefore fewer ramets. In addition, late freezes can quickly wipe out above ground growth for the year, and should be considered when collecting census data (Case pers. comm. 1997). Plant is occasionally cultivated.
Separation Barriers: EOs are separated by either:
* a distance of at least 1 km of unsuitable habitat; or
* a distance of at least 1 km of apparently suitable habitat that is not known to be occupied.

Separation Distance for Unsuitable Habitat: 1 km
Separation Distance for Suitable Habitat: 1 km
Separation Justification: The distance for unoccupied but suitable habitat is set equal to the distance for unsuitable habitat because it is uncertain how far the small seeds and pollen are dispersed and what selection factors may be preventing or promoting habitats to be colonized (Case pers. comm. 1997; Case 1994).

Date: 15Mar1997
Author: B. Nichols
Population/Occurrence Viability
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Excellent Viability: Populations of more than 500 plants with sufficient numbers of both juvenile and adult individuals to indicate successful population maintenance deserve this rank. Populations occur in excellent habitats of large-size and high natural integrity (jack pine forests, sandy forested old dunes, pine and/or aspen-jack pine-oak forests, limestone woodlands, mixed and coniferous woods along Great Lakes shores, mesic pine woods or bogs/swamps with a thin sphagnum under-carpet). All habitats of this rank are not subject to logging, manipulations of water table, or other unnatural destructive events, and are surrounded by sufficient buffer to adequately protect the site. The integrity of biotic and abiotic factors, community structure, and processes within (condition) and surrounding (landscape context) the occurrence and the degree to which they affect the continued existence of the EO should be excellent to receive an "A" rank.
Good Viability: Populations of 101-500 plants with recruitment as above deserve this rank. Populations occur in moderate-sized habitats as described above. Such habitats may show low levels of anthropogenic disturbance, but are largely natural. The integrity of biotic and abiotic factors, community structure, and processes within (condition) and surrounding (landscape context) the occurrence and the degree to which they affect the continued existence of the EO can be good to excellent to receive a "B" rank. Occurrences exceeding minimum landscape and habitat conditions and other criteria described for a defined population size remain at the rank specified by the population size unless the population size is close to that required by the next higher rank.
Fair Viability: Populations of 21-100 plants with recruitment as above deserve this rank. Populations occur in small-sized habitats as described above. Also included under this rank are shady, acidic, sandy habitats in oak woods that sometimes support small populations and habitats that show signs of moderate levels of anthropogenic disturbance. Although apparently not permanently detrimental to most populations, light or selective logging (except as a management procedure designed for this species) may threaten small populations and cause a rank to fall to this level. The integrity of biotic and abiotic factors, community structure, and processes within (condition) and surrounding (landscape context) the occurrence and the degree to which they affect the continued existence of the EO can be fair to excellent to receive a "C" rank. Occurrences exceeding minimum landscape and habitat conditions and other criteria described for a defined population size remain at the rank specified by the population size unless the population size is close to that required by the next higher rank.
Poor Viability: Populations of less than 21 plants deserve this rank. Occurrences found in clearcut areas are unlikely to be able to withstand the effects of full sun and habitat destruction. Habitats that have become severely fragmented by development pressure, occur in indefensible areas (rights-of-way, etc.), or have been affected by water table manipulations (bog drainage, etc.) are also of this rank. The integrity of biotic and abiotic factors, community structure, and processes within (condition) and surrounding (landscape context) the occurrence and the degree to which they affect the continued existence of the EO can be poor to excellent to receive a "D" rank. Occurrences exceeding minimum landscape and habitat conditions and other criteria described for a defined population size remain at the rank specified by the population size unless the population size is close to that required by the next higher rank.
Justification: A Rank: EOs in the future probably will not significantly exceed the best that currently exist (largely in close proximity to the Great Lakes), so the "A"-rank criteria are set based on the characteristics of the largest, most stable, and most viable natural occurrences currently in existence. Occurrences not meeting landscape and habitat conditions and other criteria described for a defined population size may fall to a lower rank, at the discretion of the surveyor. In general, population size is the primary factor influencing EO rank.

C Rank: EOs not reaching CRANKSPECS often occur in degraded habitats and are not likely to survive for extended periods due to low viability and susceptibility to extirpation from stochastic events.

Key for Ranking Species Element Occurrences Using the Generic Approach (2008).
Date: 15Mar1997
Author: B. Nichols
Notes: NHNHP
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 02Feb1993
NatureServe Conservation Status Factors Author: Qureshi, B., L. Morse, S. Young and M. Penskar; Wayne Ostile, rev. K. Gravuer (2008)
Management Information Edition Date: 01May1990
Management Information Edition Author: WAYNE OSTLIE, rev. K. Gravuer (2008)
Element Ecology & Life History Edition Date: 01May1990
Element Ecology & Life History Author(s): OSTILE, WAYNE

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

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