ELEMENT STEWARDSHIP ABSTRACT
Platanthera leucophaea, prairie fringed orchid
Platanthera praeclara, western white-fringed orchid
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>== 0012 STEW-ABS-RESP
THE NATURE CONSERVANCY
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MINNEAPOLIS, MN 55414
>== 0016 PREPARIER
>== 0020 NAME
PLATANTHERA PRAECLARA (PMORCIYOSO)
>== 0050 COMMON-NAME
PRAIRIE FRINGED ORCHID
WESTERN WHITE-FRINGED ORCHID
>== 0100 DESCRIPTION
In a recent taxonomic treatment (Sheviak and Bowles 1986), Platanthera praeclara was segregated from P. leucophaea as an allopatric species. Differences in flower size and structure have served to separate the two species. Specifically, the differences in column morphology result in specialized placement of pollinaria onto pollinators. This has brought about speciation through mechanical isolation and pollinator specificity (Sheviak and Bowles 1986).
Additionally, the two species appear to be separated by geographical distribution. Sheviak and Bowles (I 986) delineate the tallgrass prairie habitat to the west of the Mississippi River as supporting P. praeclara. P. leucophaea is the recognized species occurring in a variety of habitats east of the Mississippi. A sympatric range may be found in eastern Iowa south through central Missouri to eastern Oklahoma (Bowles and Duxbury 1986). Sheviak and Bowles (1986) propose the common name Western Prairie fringed orchid for P. praeclara and the name Eastern Prairie fringed orchid for P. leucophaea. Those names have been adopted for use in this ESA. Both species collectively are referred to as the Prairie fringed orchid.
The Prairie fringed orchids are stout, erect, herbaceous plants, glabrous throughout; standing from 4 to 10 cm in height. The leaves are lanceolate to broadly lanceolate, up to 26 cm long, the upper leaves are reduced. Plants arise from perennial fusiform tubers (Luer 1975, Sheviak and Bowles 1986).
The two species differ on floral characters, many related to size. A shorter raceme (5-12.6 cm) coupled with fewer flowers per raceme tends to make the inflorescence of P. praeclara appear more dense than that of P. leucophaea (raceme 8-20 cm long). The flowers of P. praeclara are larger than those of P. leucophaea. The most significant difference between the two species is the size and structure of the column. The column characters have proven constant in field studies over a wide geographic range (Sheviak and Bowles 1986).
In the genus Plantanthera, pollen is contained in small, stalked structures called pollinaria that are positioned laterally to the stigma. Attached to the stalk or caudicle, is a sticky pad or viscidium that will adhere to anything that brushes against it. In P. praeclara, the column is small and rounded, the pollinaria are closely spaced with the caudicles parallel to each other, and the viscidia are 1.2-3.2 mm apart. The column of P. praeclara is large and angular, the caudicles are widely divergent, and the viscidia are 6.2-7.5 mm apart (Sheviak and Bowles 1986).
The flowers of P. leucophaea tend to be pure white with green sepals while those of P. praeclara are more creamy white with a green tint in otherwise creamy white sepals (Sheviak and Bowles 1986). Both have very long nectar spurs that can reach 50 mm in length. The fringed, trilobed lip is similar in both species, however, the lobes of P. leucophaea are broad and downward spreading (Sheviak and Bowles 1986).
The Prairie fringed orchids may occasionally be confused with P. lacera, the Ragged-fringed orchid. The flowers of P. lacera are much smaller and are usually greenish. The nectar spur on P. lacera does not exceed the length of the ovary (Bowles and Duxbury 1986).
>== 1000 HABITAT
According to Sheviak and Bowles (1986), P. praeclara appears to be restricted to tallgrass prairie areas within the Missouri River drainage. P. leucophaea is found to the east of the Mississippi River in the Great Lakes Region and the area that comprises the prairie peninsula. It is thought that P. leucophaea may have expanded eastward with the extension of the prairie peninsula and then adapted to the diverse habitats encountered (Sheviak and Bowles 1986).
P. praeclara occurs in the mesic tallgrass prairie hay meadows in Missouri, Kansas, North Dakota, Oklahoma, Iowa, and Nebraska (Kurz, McGregor, Bowles, Magrath, Leoschl,,e, Kaul pers. comm.). Soils are primarily loess over Kansan or Wisconsin drift in Missouri, Kansas, Iowa, and Nebraska; and in thin loess over residuum in Oklahoma (Bowles and Duxbury 1986). This species is also found on the lower slopes of wet prairie swales in Minnesota, North Dakota, and Manitoba (Smith, Bowles, Catling pers. comm.). Habitats include mesic prairies and sedge meadows in Iowa (Leoschke pers. comm.), and a floodplain sedge meadow with alluvial soils in Nebraska (Currier pers. comm.).
In general, soils tend to be circumneutral. See Bowles 1983, and Bowles and Duxbury 1986 for more detailed information on soil types of P. praeclara habitat.
Associates in Minnesota include: Spartina pectinate, Carex sartwellii, Juncus balticus, Triglochin maritima, Cicuta maculata (Smith pers. comm.); in Nebraska P. praeclara is found in association with Asclepias verticillata, Andropogon gerardi, Sorghastrum nutans, Kuhnia eupatorioides, Amorpha canescens, and Solidago rigida (Twedt pers. comm.). For additional associates, see Bowles and Duxbury 1986.
P. leucophaea is found in mesic to wet prairies in Illinois, Ontario, and Wisconsin (Packard, Catling, Newsome pers. comm.). Soils are usually deep, black, calcareous to circumneutral (Bowles 1983). P. leucophaea is also found in wet sedge meadows in Wisconsin, Maine, Illinois, Virginia, and Ontario (Alverson 1981; Forrester, Schwegman, Wieboldt, Catling pers. comm.). Around the Great Lakes in Michigan, Wisconsin, Illinois, and Ontario P. leucophaea is found in a low dune and swale lakeplain habitat of wet to mesic prairie (Chapman, Martin, Packard pers. comm.). The soils are circumneutral to highly alkaline sandy loams and loams (Chapman pers. comm.). Peripheral habitat includes sedge-sphagnum bog mats in kettle lakes containing water of neutral pH in Michigan (Chapman pers. comm.); and abandoned agricultural fields in Ohio, Michigan, and Ontario (Bums, Chapman, Catling pers. comm.). For more details on soils, see Bowles 1983.
Associates in Illinois mesic prairies include: Asclepias sullivantii, Andropogon gerardi, Cacalia tuberosa, Cicuta maculata, Ratibida pinnata, Liatris spicata, Coreopsis lanceolata, Cypripedium candidum, and Lobelia spicata (Bowles and Kurz 1981). In Wisconsin prairies, associates include: Spartina pectinate, Sorghastrum nutans, Anemone canadensis, and A. cylindrica (Newsome pers. comm.). Associates in the fen sedge meadow in Maine include: Potentilla fruticosa, Thuja occidentalis, Betula pumila, Kalmia angustifolia, and K. polifolia (Forrester pers. comm.). In Virginia, P. leucophaea is found with Leersia oryzoides, Rhynchospora sp., Spartina pectinate, Lythrum alatum, Equisetum fluviatile and Juncus dudleyi (Fenwick, Wieboldt pers. comm.). One of the abandoned farm fields in Ohio is dominated by Phalaris arundinacea (Bums pers. comm.), the other field has the following associates Lythrum salicaria, Solidago canadensis, and Convolvulus sepium (Bender 1984).
>== 2000 BIOLOGY-ECOLOGY
The Prairie fringed orchids are perennial plants with fusiform tubers (Bowles 1983). The tubers regenerate vegetatively during the growing season by forming a new primary tuber and a perennating bud which will develop into the new root system and aerial shoot for the following growing season (Bowles 1983).
Vegetative reproduction is very uncommon. If the tuber of P. leucophaea is damaged, two plants may form (Case pers. comm.). Bowles has occasionally observed multiple tuber formation in P. praeclara (Bowles and Duxbury 1983). The tubers become separated over time and result in two single plants. Since vegetative reproduction is so uncommon, population maintenance for these two species is dependent on long-term survival of adults and seed reproduction (Bowles and Kurz 1981).
The aerial shoot appears above ground in late spring-early May in the south, late May in the north (Bowles and Duxbury 1986). The plant develops vegetatively for two months and begins to bloom by late June in the south, to late July in the north (Bowles and Duxbury 1986). Throughout the Midwest, in adjacent Indiana, Ohio and southern Wisconsin, the plant peaks in bloom during the first week of July. Flowers open from the bottom of the inflorescence, a few per day. Individual flowers can last up to ten days, with an inflorescence presenting flowers for three weeks.
The Prairie fringed orchids exhibit the features characteristic of moth-pollinated flowers; white flowers with no nectar guides, sweet nocturnal fragrance, and nectariferous spurs (Sheviak and Bowles 1986). The primary pollinators are members of the Sphingidae (Sphinx moths). The pollen vectors captured or observed on P. leucophaea are Xylophanes tersa, Eumorpha achemon, Sphinx eremitis and Manduca sexta. Pollination has not been observed on P. praeclara, but it is thought that other moths in the Sphingidae would pollinate this species (Sheviak and Bowles 1986).
When a Sphinx moth visits a flower of P. leucophaea, it inserts its proboscis into the nectar spur through an entrance placed strategically between the two pollinaria and their sticky viscidia. The short distance between the viscidia insures that the moth will touch one of them with its proboscis. The pollinarium is pulled from the flower as the moth retracts its proboscis.
As the moth travels to the next flower, the caudicle or stalk on the pollinarium changes position by bending forward until the caudicle is almost parallel to the proboscis. In this position, the pollinarium will come in contact with the stigma of the next flower visited (Sheviak and Bowles 1986).
In a caged situation, one short-tongued moth came away from P. praeclara with a pollinariwn on its eye. To pollinate P. praeclara, a moth must have eyes placed at the precise distance on its head to come in contact with the wider spaced viscidia. The placement of the proboscis into the nectar spur would not result in contact with the widely spaced viscidia. The caudicle on P. praeclara rotates to the right or left, assuming a central position on the moth's head.
The specialized placement of pollinaria on the moths provides a mechanical barrier to hybridization between the two species. The laterally placed pollinarium of P. praeclara won't reach the recessed stigma of P. leucophaea and the forward pointing pollinarium of P. leucophaea will not contact the stigma of P. praeclara, positioned above the entrance to the nectar spur, which is where the moth will be thrusting it proboscis (Sheviak and Bowles 1986).
Long-tongued moths are nectar thieves on P. praeclara (Bowles pers. comm.). Their probosci never touch the widely spaced viscidia, but can still take nectar from the flowers. Moths with shorter tongues and wide-set eyes will effect pollination in P. praeclara (Sheviak and Bowles 1986).
Due to deposition of the pollinarium on the proboscis, P. leucophaea can adapt to a wider variety of pollinators than can P. praeclara. It may be that this adaptation enabled P. leucophaea to spread eastward, exploiting a diversity of moths in the various habitats encountered. P. praeclara may be restricted in the tallgrass region by its pollinator specificity (Sheviak and Bowles 1986).
Fruit set appears to be variable. In Wisconsin, Alverson (I 98 1) observed that 70-1 00% of the ovaries on each plant set seed. Smith (pers. comm.) has also noted abundant seed set in Minnesota. In general, Bowles (pers. comm.) found much lower fruit set in the wide range of areas he sampled. Information on fruit set for both species is forthcoming from Bowles (pers. comm.).
Capsules dry and dehisce by September and the dust-like seed is blown by the wind. The interval from seed dispersal to germination is unknown. Orchid seeds are resistant to wetting and may not readily take up water to cause germination (Curtis 1943). Curtis (1 943) suggested it might take several years for Cypripedium seeds to be transported to a suitable depth in the soil or to be covered up by soil. Seedling establishment is also dependent upon the presence of mycorrhizal flmgi and the establishment of a successful symbiotic relationship between the developing protocorm and the fungi.
The interval from seed germination to first flowering is unknown. Seedlings appear as single, small strap-like leaves (Smith pers. comm.). Older vegetative plants are often just two leaves at the ground surface. Some vegetative plants will produce a leafy stem but not flowers (Smith pers. comm.).
Plants in a population are usually scattered. Densities of 6 plants per square meter have been observed in Minnesota (Smith pers. comm.), but generally Bowles has found an average of .0 I plants per square meter. See Bowles 1983 for a list of plant densities by community type.
The Prairie fringed orchids are noted for erratic mass flowerings followed by years of absence or lownumbersoffloweringplants. SheviakandBowles(1986)suggestthatinyearsof suboptimal growing conditions, the plants revert to a subterranean dormant or heterotrophic state foroneormoreyears. Alverson(1981)speculatesthatthefluctuationsreportedmaynotbe tal-,ing the inconspicuous vegetative plants into account. There is no proof that either species can or does revert to a subterranean existence once it has reached maturity (Case pers. comm.). Catling (pers. comm.) has found vegetative plants after some searching in places where others had said the plants had disappeared after a mass blooming.
Sheviak (1984) suggests that the mass flowering phenomena is brought on by fires that stimulate the plants to break dormancy. With the removal of the litter layer, the increased insolation may increase vegetative growth and mycorrhizal activity (Bowles and Duxbury 1986).
The patches of bare ground opened by fire may be ideal for seedling establishment. P. leucophaea has been observed colonizing ditches and fallow fields of former wet prairies from seed sources on adjacent native habitat (Chapman and Crispin 1985). Other populations have survived in fields that were cultivated for a number of years. P. praeclara has also been observed in ditches (Smith pers. comm.).
Sheviak and Bowles (I 9 8 6) point out that in addition to fire stimulation, edaphic factors such as soil moisture may be critical in causing the mass flowerings. Twedt (pers. comm.) attributes the appearance of a large colony of P. praeclara on a site burned in early May to the burn and the seven to eight inches of rain that fell in the six weeks following the burn.
>== 2500 EO-QUAL-DET
>== 3000 THREATS
The Prairie fringed orchids are threatened by loss of habitat from draining and ditching for crop production, and commercial and residential development. Populations along the shores of the Great Lakes are presently threatened by high water levels and invasion of purple loosestrife. In the past, beavers have flooded sites in Ohio and Virginia. Cattle and deer will graze the flowering stems. Cutting hay in mid-summer prevents those populations occurring in prairie hay meadows from setting or dispersing seed. Fire exclusion has allowed woody shrubs to invade some prairie sites. Populations are also threatened by collection from orchid fanciers and wildflower gardeners.
Herbivory at two sites in Minnesota destroyed the above-ground growth of both flowering and vegetative plants of both populations in 1986. Since these two sites may represent 20% of the total range-wide population (Smith pers. comm.), there is cause for serious concern. Plants were eaten off at or below ground level. Insects such as a stem borer or cut leaf worm are suspected, but rodents are another distinct possibility.
>== 3500 LAND-PROT-SPECS
The Prairie fringed orchids occur in open habitats. The plants cannot tolerate shading (Alverson 1981, Bowles 1983, Case pers. comm.). A preserve should be large enough that prairie maintenance, i.e. fire, can be safely conducted. Include sufficient buffer to prevent ditching or draining on adjacent property which could seriously alter the water table. If the area is fed by a spring, secure the source of the spring to prevent damaging fluctuations in the water table.
>== 4000 RECOVERY-POT
Recovery potential for a degraded site is unknown. If the site is overgrown with woody species, it should be managed with fire or brush cutting to restore the open habitat. P. leucophaea appears to be able to withstand some disturbance. Case (1964) observed plants seeding into drainage ditches in a former wet prairie site. Plants of P. leucophaea have been found in abandoned farmland, and one population in Michigan recovered after one year in cultivation (Chapman and Crispin 1985).
Growing the plants from seed to restock depleted populations is not feasible. No one has yet successfully reared either species to maturity (Case, Stoutamire pers. comm.). Case (pers. comm.) has grown mature plants of P. leucophaea for thirty-five years after transplanting them into a wet meadow from a site slated for destruction. He emphasizes that with suitable soils and growing conditions, this species of Plantanthera is one of the easiest to grow.
>== 5000 BIOL-MONIT-NEEDS
Monitoring should be used to track the accomplishment of conservation and management goals. The main objectives for management should include maintaining population size for those occurrences in good condition; increasing population size for occurrences declining from woody vegetation invasion; and preventing drainage of wetlands or lowering of the water table in areas adjacent to the area that supports an orchid population.
>== 5200 BIOL-MONIT-PROCS
Gathering reliable baseline information on populations of P. leucophaea and P. praeclara will be challenging. Land managers should keep in mind that it is difficult to determine population sizes for the Prairie fringed orchids due to the erratic fluctuations in flowering. Vegetative plants are difficult to see in the dense mid-summer vegetation and some plants in a population may be present only in a dormant subterranean condition (Bowles and Duxbury 1986). Refer to numbers from past sighting (if available for a population) as a guide to what can be expected under optimal conditions.
Population size should be monitored by censusing the entire population if it is small, or by censusing a sample area for large populations. Permanent plots would be useful for annual censusing of subpopulations and for noting recruitment and mortality in those populations that are being maintained at present numbers. Besides monitoring the orchid, monitor the potential for drainage or water table fluctuations by inspecting the land within the watershed and by observing vegetation changes brought on by drying of the soil. Wells can be put in to obtain accurate information on water-level fluctuations.
>== 5400 BIOL-MONIT-PROGS
In Minnesota, Welby Smith is monitoring several populations of P. praeclara using his bicoordinate system. He is recording the number of leaves, number of flowers per inflorescence and stem height. Contact Smith at the Minnesota Natural Heritage Program, @ DNR, St. Paul, @ 55146.
In Michigan, populations of P. praeclara have been monitored for the last four years. Individual plants have been marked and mapped. Information recorded for each plant includes number of flowers per inflorescence, number of leaves, and plant height. Contact: Sue Crispin,
Coordinator, Michigan Natural Features Inventory, Lansing, MI 48909.
At one site in Ohio, all plants of P. leueophaea occurring within five 20 meter belt transacts are counted each year. Contact: Jim Bums, Botanist, Ohio Heritage Program, Columbus, OH 43224. Presence/absence has been noted for other Ohio sites by TNC staff. Contact: Larry Smith, Director of Science and Stewardship, The Nature Conservancy, 15 04 West I st Ave., Columbus, OH 43212.
In Virginia, the site is monitored for presence/absence of P. leucophaea. Contact: George Fenwick, Director, Virginia Nature Conservancy, 619 E. High St., Suite 2, Charlottesville, VA 22901.
In Nebraska, monitoring at one prairie includes counting the number of flowering vs. nonflowering plants of P. praeclara. A grid system has recently been established at this site for prairie research. Contact: Curtis Twedt, NE Game and Parks Commission, Lincoln, NE 68503.
In Missouri, Don Kurz has marked and mapped plants of P. praeclara. He is tracking individual plants each year and is noting the number of flowering vs. non-flowering plants. Contact: Don Kurz at Missouri Natural History Section, Missouri Dept. of Conservation, Jefferson City, MO 65102.
In Illinois, Bowles is recording presence/absence and working on demography in populations of P. leucophaea. Contact: Marlin Bowles at the Morton Arboretum, Lisle, IL 60532.
In Maine, P. leucophaea has been monitored for the past four years. In 1984, plants were permanently marked and mapped. Contact: Barbara Vickery, Stewardship Director, Maine Chapter of The Nature Conservancy, 122 Maine St., Topsham, ME 04086.
In Iowa, Leoschke hopes to start collecting demographic information in 1987. Contact: Marl-, Leoschke, Botanist, Iowa Natural Areas Inventory, Iowa DNR, Wallace State Office Building, Des Moines, IA 50319.
At two sites in Wisconsin, presence/absence has been observed for several years. Contact: Jill Bedford, TNC volunteer, Wisconsin Chapter of The Nature Conservancy, 1045 E. Dayton St., Rm. 209, Madison, WI 53703.
A grid system established at another site to aid in prairie management will also be used to collect information on P. leucophaea. Contact: Dick Newsome, Beloit College, Beloit, WI 5351 1.
>== 6000 RSRCH-NEEDS
>== 6010 RSRCH-NEEDS-COMM
The highest priority for research is / determining the conditions required for seedling establishment and survival to maturity. Are patches of bare soil necessary for seed germination and seedling establishment? What is the interval between seed dispersal and seed germination? More information is needed on the myconhizal relationships between seedlings and mature plants. Do mature, reproductive individuals revert to a heterotrophic subterranean existence? If so, what induces it? What is the greatest duration of such an existence? What breaks this dormant or heterotrophic condition? The factors that are responsible for fluctuations in flowering require investigation. What are the effects of fire on the Prairie fringed orchids? Gene exchange in small populations may be impacted more severely than in large populations by fluctuations in flowering cycles. Are pollinators more likely to visit large patches of orchids rather than solitary flowering stems? What is the identity of the herbivore or herbivores responsible for damaging the Minnesota populations?
Smith (pers. comm.) has suggested several methods to capture possible pests at the damaged Minnesota sites, including light traps and pit traps for insects, and small mammal traps in addition to direct observation of the plants at each site once a week during the growing season. Contact Welby Smith or Rick Johnson, Assistant Director of Stewardship, Minnesota Field Office of The Nature Conservancy for more infon-nation on the herbivory problem.
The response of P. praeclara to different grazing schedules is being studied at Mormon Island in Nebraska. Contact: Paul Currier, Plant Ecologist, Platte River Whooping Crane Habitat. Maintenance Trust, Grand Island, NE 68801.
>== 6400 RSRCH-PROGS [Y N Ul N
>== 6410 RSRCH-PROGS-COMM
>== 7000 MGMT-NEEDS [Y N Ul
>== 7010 MGMT-NEEDS-COMM
The Prairie fringed orchids are shade intolerant. Management to control competing woody growth is essential for maintaining or increasing populations of this orchid. Management to maintain the prairie community is necessary. This may involve prescribed burning, haying, and/or grazing. Management by fire may also be needed to stimulate mass flowering of Prairie fringed orchids. Some sites may be threatened by loss of soil moisture or by inundation from water levels that are too high. Steps should be taken to maintain proper moisture.
>== 7400 MGMT-PROCS
To control competing woody growth, shrubs should be cut when carbohydrate reserves are lowest, after the leaves appear. Cut stumps may be treated with herbicides.
Fire appears to stimulate mass flowering in the Prairie finged orchids (Sheviak 1974, Bowles 1983). The direct relationship between fire and flower production is unknown, but indirect factors such as a reduction in litter and a reduction in the invasion of woody vegetation improves growing conditions.
Many sites of P. praeclara are prairie hay meadows that are mowed and raked at some point from mid-summer to fall depending upon the individual landowner's needs. Hay meadows should not be mowed prior to seed dispersal in the fall. Hay may be able to be harvested in other portions of a meadow that do not support the orchid.
Bowles (1983) suggests that moderate grazing could reduce competition and promote flowering. He cites plants surviving under seasonal grazing in Cheyenne National Grasslands to support his hypothesis. Season-long cattle grazing, however, appears to be incompatible with management of the Prairie fringed orchids because cattle have been known to graze the flowering stems, trample vegetative plants, and compact the soil (Bowles and Duxbury 1986).
To prevent loss of soil moisture in those areas fed by springs, maintain the areas around the springs to ensure the unimpeded flow, of water. Clear obstructions that might impound water flow and inundate the orchids.
Maintain suitable habitat upslope for the lakeshore sites that are presently threatened with inundation. P. leucophaea has been known to seed into suitable prairie habitat on higher ground when lakeshore swales have been flooded (Case, Chapman pers. comm., Chapman and Crispin 1985). Most upland lakeshore prairie habitat has been destroyed by farming. These areas need to be restored to prairie or at least open meadow to support populations of P. leucophaea retreating from the high lake levels (Chapman and Crispin 1985).
>== 7700 MGMT-PROGS [Y N U]
>== 7710 MGMT-PROGS-COMM
The Prairie fringed orchids occur in the following areas because of or in spite of management procedures aimed at maintaining the community, not an individual species.
In Iowa, sites are burned by the first week in May once every two or three years. Contact: Mark Leoschke, Botanist, Iowa Natural Areas Inventory, Wallace State Office Building, Des Moines, IA 50319.
Plans for one prairie site in Missouri call for haying in late August every other year and burning in April the alternate year (Kurz pers. comm.). The dwarf chestnut oak Quercus prinoides also occurs in this prairie. Since it is a native component of the prairie, only those shrubs shading the orchids are cut, usually in June. Roundup has also been applied to these shrubs in a most effective manner. Kurz (pers. comm.) describes wiping leaves and branches while wearing a cloth glove (over a rubber glove) that has been dipped in the herbicide. Contact: Don Kurz, Missouri Natural History Section, Missouri Department of Conservation, Jefferson City, MO 65102.
In Nebraska, one site is hayed each year in early-to-mid-September. The site has burned once since 1984. Contact: Curtis Twedt, Nebraska Game and Parks Commission, Lincoln, Nebraska 68503.
Another location in Nebraska is burned in April and resprouts are grazed off. Two hundred head of cattle are rotated through four pastures, one of which contains about 50 plants of P. praeclara. Each pasture is grazed at different times each year. Contact: Paul Currier, Platte River Whooping Crane Habitat Maintenance Trust, Grand Island, Nebraska 6990 1.
In Wisconsin, sites are burned every three years in April. Willow,and dogwood are cut in the fall. Contact: Mark Martin, Wisconsin Natural Heritage Program, WI DNR, Madison, WI 53707 or Brent Haglund, Director, Wisconsin Chapter, The Nature Conservancy, Madison, WI 53703.
In Ohio, one site is burned in April to remove litter. Contact: Jim Burns, Ohio Heritage Program, OH DNR, Columbus, OH.
In Illinois, Roundup will be sprayed on Dipsacus laciniatus in the winter of 1986 to remove those plants that are crowding out P. leucophaea in a prairie cemetery. For other prairie sites, Steve Packard has planned a bum cycle that alternates with spring and fall burns and also varies the frequency of bums at each site. Contact: Steve Packard, Illinois Chapter, The Nature Conservancy, Chicago, IL 60603.
>== 8000 SUM-STEW-NEEDS
Active management is essential for perpetuation of the shade-intolerant Prairie fringed orchids. Burning and brush cutting rather than haying are the methods suggested by many land managers. Monitoring should be used to track the major management concerns regarding population size maintenance and water table fluctuations. Important research questions are concerned with seed germination and seedling establishment, factors related to flowering fluctuations, possible reversion of mature autotrophic plants to a heterotrophic subterranean existence, and what constitutes a minimum number of individuals to effectively attract pollinators.
>== 9000 BIBLIOGRAPHY
Alverson,W.S. 1981. UnpublishedreporttotheU.S.FishandWildlifeServiceonthe
Wisconsin status of Plantanthera leucophaea. Scientific Areas Section, Wisconsin Dept. Nat. Res., Madison. 17pp.
Bender, Marty. 1984. Unpublished report to the Ohio Field Office, The Nature Conservancy on the Initial Survey of Ottawa Marsh.
Bowles, M.L. 1983. The tallgrass prairie orchids Platanthera leucophaea (Nutt.) Lindl. and Cypripedium candidum Muhl. ex. Willd.: Some aspects of their status, biology, and ecology, and implications toward management. Natural Areas J. 3:14-37.
---------. 1986. October. Botanist, Morton Arboretum, Lisle, IL. Telephone conversation with J. Bender, The Nature Conservancy, Midwest Regional Office, Minneapolis, MN.
and A. Duxbury. 1986. Report on the status of Platanthera praeclara. Sheviak and Bowles in Oklahoma, Kansas, Nebraska, South Dakota, and North Dakota. Report submitted to U.S. Fish and Wildlife Serv., Denver, CO 80225.
Bowles, M.L. and D. Kurz. 1981. Unpublished report to the U.S. Fish and Wildlife Service on the Illinois status of Platanthera leucophaea. Natural Land Institute, Rockford. 7pp.
Bums, Jim. 1986. Oct. 3. Botanist, Ohio Natural Heritage Program, Columbus. Telephone conversation with J. Bender, The Nature Conservancy, Midwest Regional Office, Minneapolis, MN.
Case, F.W., Jr. 1964. Orchids of the Western Great Lakes Region. Cranbrook Institute of Science, Bloomfield Hills, Michigan.
---------. 1986. Oct. 7. Telephone conversation with J. Bender, TNC, MRO.
Catling, Paul. 1986. Oct. 2. Research Scientist, Agriculture Canada, Ottawa. Telephone conversation with J. Bender, TNC, MRO.
Chapman, Kim. 1986. Oct. 6. Regional Ecologist, Midwest Office, The Nature Conservancy, Minneapolis, MN. Personal interview with J. Bender, TNC, MRO.
----------- and S. Crispin. 1985. A comprehensive survey for Platanthera leucophaea (Prairie white fringed orchid) in Michigan. Michigan Natural Features Inventory, Lansing, MI 48909.
Currier, Paul. 1986. Oct. 1. Plant Ecologist, Platte River Whooping Crane Habitat Maintenance Trust, Grand Island, NE 68801. Telephone conversation with J. Bender, TNC, MRO.
Curtis, J. T. 1943. Germination and seedling development in five species of Cypripedium L. Amer. J. Bot. 30:199-205.
Fenwick, George. 1986. Oct. 2. Director, Virginia Chapter, The Nature Conservancy.
Telephone conversation with J. Bender, TNC, MRO.
Forrester, Amy. 1986. Oct. 2. Botanist, Maine Natural Heritage Program. Telephone conversation with J. Bender, TNC, MRO.
Heitlinger, Mark. 1986. Oct. Midwest Region Director of Stewardship, The Nature Conservancy, Minneapolis, MN. Personal conversation with J. Bender, TNC, MRO.
Kaul, Robert. 1986. Oct. 1. Professor, University of Nebraska, Lincoln. Telephone conversation with J. Bender, TNC, MRO.
Kurz, Don. 1986. Oct. 1. Missouri Natural History Section, Missouri Department of
Conservation, Jefferson City, MO 65102. Telephone conversation with J. Bender, TNC, MRO.
Leoschke, Mark. 1986. Oct. 6. Botanist, Iowa Natural Areas Inventory, Wallace State Office
Building, Des Moines, IA 50319. Telephone conversation with J. Bender, TNC, MRO.
Luer, C.A. 1975. The native orchids of the United States and Canada, excluding Florida. New York Bot. Garden. 3 6 1 pp.
Magrath, Larry. 1986. Oct. 3. Professor, Oklahoma University of Science and Arts. Telephone conversation with J. Bender, 'fNC, MRO.
Martin, Mark. 1986. Oct. 2. Natural Areas Management Specialist, Wisconsin Natural Heritage program, WI DNR, Madison 53707. Telephone conversation with J. Bender, TNC, MRO.
McGregor, Ron. 1986. Oct. 1. Professor, University of Kansas. Telephone conversation with J. Bender, TNC, MRO.
Newsome, Dick. 1986. Oct. 3. Professor, Beloit College, Beloit, WI. Telephone conversation with J. Bender, TNC, MRO.
Packard, Steve. 1986. Oct. 3. Field Representative, Illinois Field Office, The Nature Conservancy, Chicago, IL. Telephone conversation with J. Bender, TNC, MRO.
Schwegman, John. 1986. Oct. 3. Botanist, Illinois Dept. Conservation, Springfield, IL.
Telephone conversation with J. Bender, TNC, MRO.
Sheviak, C.J. 1974. An introduction to the ecology of the Illinois Orchidaceae. 111. St. Mus. Sci.
----------and M.L. Bowles. 1986. The Prairie fringed orchids: A pollinator-isolator species pair. Rhodor 88:267-290.
Smith, Welby. 1986. Oct. 3. Botanist, Minnesota Natural Heritage Program, MN DNR, St. Paul. Telephone conversation with J. Bender, TNC, MRO.
Stoutamire, Warren. 1986. Oct. 2. Biology Professor, University of Akron, Ohio. Telephone conversation wit J. Bender, TNC, MRO.
Twedt, Curt. 1986. Oct. 2. Nebraska Game and Parks Commission, Lincoln. Telephone conversation with J. Bender, TNC, MRO.
Wireboldt, Tom. 1986. Oct. 2. Herbarium Curator, Virginia Tech. Telephone conversation with J. Bender, TNC, MRO.
>== 9900 UPDATE [YY-MM-DDI 86-11-20