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Conserving and restoring
America's native plants
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CPC National Collection Plant Profile
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Pyxidanthera barbulata
| Family: |
Diapensiaceae (Diapensia Family) |
| Common Names: |
flowering moss, flowering pixie-moss, pixie-moss |
| Taxon Synonyms: |
Pyxidanthera barbulata var. brevifolia, Pyxidanthera brevifolia Wells |
| Author: |
Michx. |
| Growth
Habit: |
Subshrub |
| CPC
Number: |
7047 |
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| Primary
custodian for this plant in the CPC National Collection of Endangered
Plants is: |
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| Elizabeth J. Farnsworth contributed to this Plant Profile. |
Pyxidanthera barbulata
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Pyxidanthera barbulata is a diminutive, creeping evergreen sub-shrub that forms dense mats sprinkled with delicate white-pink flowers. Its prostrate growth form and crowded tiny leaves allow the plant to conserve water in the very xeric habitats in which it occurs. Its habitat includes the back-barrier dunes of southern Long Island, throughout the dwarf pine plains of New Jersey, among the last remaining longleaf pine stands of Virginia, to the sandhills of the Carolinas.
Research and Management Summary:
A handful of individuals and institutions have conducted research, management and monitoring on this particular species.
Plant Description:
Pyxidanthera barbulata is a mat-forming, woody, evergreen sub-shrub with needle-like, pine-green leaves that are hairy near their bases. The 5-8 mm-wide, white to rose-colored flowers are distinctive and characteristic of the family, with widely separated petals surrounding a slender style encircled in the protruding, inflexed anthers.
| Distribution
& Occurrence |
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State Range
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New Jersey
New York
North Carolina
South Carolina |
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Habitat
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Pyxidanthera barbulata is found in droughty, acidic sandy soils under an open or thin canopy of pines. Although it is typically described from xeric habitats, the plant is termed a facultative wetland associate (USDA 2001), and listed with keys to aquatic and wetland plants (Godfrey and Wooten 1981). Wells and Shunk (1931) record it from "coarse sand areas of low relief having a high water table for extended periods alternating with depressed water table in drought years." Thus, the plant can tolerate a broad range of hydrological conditions. The morph occupying xeric environments was once thought to be a separate species or variety (brevifolia) from P. barbulata (Wells and Shunk 1931, Kral 1983), but other treatments recognize this variation as intraspecific plasticity and circumscribe the populations as one species (Primack and Wyatt 1975).
*On Long Island, Pyxidanthera barbulata occupies the back-dunes of the southern back-barrier of the moraine, in stands of scattered pitch pine, Pinus rigida.
*In the coastal plain of New Jersey, the plant is typically found in the dwarf pine plains of the eastern Pinelands, characterized by pitch pines under 3 m tall, along with blackjack and scrub oak (Quercus marilandica and Q. ilicifolia), with a sparse understory layer of sheep laurel (Kalmia angustifolia), mountain laurel (Kalmia latifolia), sweet fern (Comptonia peregrina), sand-myrtle (Leiophyllum buxifolium), wintergreen (Gaultheria procumbens), bearberry (Arctostaphylos uva-ursi), trailing arbutus (Epigaea repens), and patches of broom crowberry (Corema conradii) and false heather (Hudsonia ericoides) (Good et al. 1979, Obee 1994).
*Pyxidanthera barbulata is noted from tracts containing the northernmost longleaf pine (Pinus palustris) in the east (Sheridan et al. 2001), and occurs on xeric, thinly wooded, sterile sands under longleaf pine in mainland and barrier beach areas of North Carolina (Harper et al. 1997).
*In South Carolina, the species is recorded from the sandhills region. |
Distribution
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Pyxidanthera barbulata occurs from southern Long Island to South Carolina along the coastal plain. Its distribution appears somewhat disjunct, as there are no current or historical records for the taxon in Delaware or Maryland, where comparable habitat on the outer coasts apparently exists. Also, all Virginia Pyxidanthera barbulata is var. barbulata. |
Number Left
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Pyxidanthera barbulata is recorded from 22 counties in North Carolina, 2 counties in South Carolina, and 3 counties in Virginia (USDA 2001). The status and distribution of this species in New Jersey is uncertain, as reflected in the state rank of S?; however, it is known from at least two sites in Ocean County, NJ.
No estimates for total population numbers are currently available. |
State/Area
Protection
| |
State/Area |
Rank |
Status |
Date |
|
| |
New Jersey |
S? |
|
|
|
| |
New York |
S1 |
E |
4/1/2001 |
|
| |
North Carolina |
S3 |
|
|
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South Carolina |
S1 |
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5/1/2000 |
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United States |
N? |
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8/1/1993 |
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| Conservation,
Ecology & Research |
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Ecological
Relationships
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• Very little information has been published on the ecological relationships of Pyxidanthera barbulata beyond basic habitat associations.
• The Diapensaceae family consists of four genera that are monotypic in eastern North America (Gleason and Cronquist 1991). Pyxidanthera barbulata shares anatomical and architectural features in common with Diapensia lapponica (a low, creeping plant of alpine summits) and Galax aphylla (which spans the Appalachian mountains to the southeastern coastal plain).
• From their studies in North Carolina, Wells and Shunk (1931) thought the taxon was "a relict species surviving today wholly on a basis of vegetative growth." They found no seedlings in the field, despite exhaustive searches, and their attempts to germinate seeds were unsuccessful.
• Low germination rates could contribute to the plant's rarity, and seed germination may be cued to fire.
• Pyxidanthera barbulata is found in communities that burn frequently, and may require fire either to physiologically stimulate germination or to open the canopy (Obee 1994, Jordan et al. 1995, Harper et al. 1997).
• Flowering times are listed as April to May (Gleason and Cronquist 1991).
• Information on pollinators is lacking, but insects are likely vectors, given the flower morphology. Seed dispersal agents are unknown. |
Threats
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• Conversion of coastal plain habitat for residential and agricultural development
• Fire suppression, leading to succession by woody vegetation that outcompetes Pyxidanthera barbulata for light |
Current Research Summary
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• Taxonomy and intraspecific variability are treated by Primack and Wyatt (1975) and Kral (1983)
• Habitat associations are described by Wells and Shunk (1931) and Good and Good (1975), but specific habitat requirements of the taxon have not been determined
• The New England Wild Flower Society maintains populations of Pyxidanthera barbulata at its garden in Framingham, Massachusetts. They have also conducted germination trials, finding that fresh seed will germinate without a cold treatment. Germinating dried seed is problematic, and seeds do not remain viable in a seed bank. Plants can be propagated from tissue culture, but growth is slow and mortality is high. Stem cuttings can be rooted, but frequently die.
• The Norcross Sanctuary in Monson, Massachusetts, has Pyxidanthera barbulata in its rare plant collection, as does Eastern Plant Specialties in Georgetown, Maine |
Current Management Summary
| |
• The U.S. Army regularly monitors populations Fort Bragg and Camp Mackall in North Carolina (Fort Bragg Endangered Species Branch 2001)
• The South Carolina Division of Forest Resources has removed scrub oaks in certain longleaf pine stands to restore habitat for Pyxidanthera barbulata, the red-cockaded woodpecker, and the pine-wiregrass ecosystem. |
Research Management Needs
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A number of studies would be beneficial to the conservation of this species, including:
• Studies of the impacts of fire on seed germination, seedling recruitment, and plant competition
• Research to identify pollinators and determine if pollinator limitation or inbreeding depression may affect populations
• Studies of the mechanisms of its seed dispersal
• Research on the responses of Pyxidanthera barbulata to variable hydrological regimes, and its capacity for seed-banking during successive dry years |
Ex Situ Needs
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• Studies of seed storage, germination physiology, and plant propagation are needed. |
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| Books (Single Authors)
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| Gleason, H.A.; Cronquist, A. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Bronx: The New York Botanical Garden. |
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| Godfrey, R.K.; Wooten, J.W. 1981. Aquatic and wetland plants of southeastern United States: Dicotyledons. Athens: University Georgia Press. 933p. |
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| Books (Sections)
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| Good, R.E.; Good, N.F.; Andreson, J.W. 1979. The pine barren plains. In: Forman, R.T.T., editor. Pine Barrens: Ecosystem and Landscape. Academic Press. New York. p 283-295. |
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| Electronic Sources
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| Miller, J.H.; Bishop, L.M. (1989). Renovating Longleaf Pine Stands for Pinestraw Raking. Adapted from USDA, Forest Service, Management Bulletin R8-MB 28. http://www.dfr.state.nc.us/source_files/release.PDF. Accessed: 2002. |
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| USDA. (2002). PLANTS profiles. [Web site] United States Department of Agriculture, Natural Resources Conservation Service. http://www.plants.usda.gov. Accessed: 2002. |
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| Journal Articles
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| Frost, C.C.; Musselman, L.J. 1987. History and vegetation of the Blackwater Ecologic Preserve. Castanea. 52: 16-46. |
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| Godt, M.J.W.; Hamrick, J.L. 1995. Low Levels of Allozyme Differentiation between Pyxidanthera (Pyxie-Moss) Taxa (Diapensiaceae). Plant Systematics and Evolution. 195, 3-4: 159-168. |
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| Good, R.E.; Good, N.F. 1975. Growth characteristics of two populations of Pinus rigida Mill. from the Pine Barrens of New Jersey. Ecology. 65: 1215-1220. |
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| Michaux, A. 1803. Flora Boreali-Americana. 1, 152-153 |
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| Primack, R.B.; Wyatt, R. 1975. Variation and taxonomy of Pyxidanthera (Diapensaceae). Brittonia. 27: 115-118. |
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| Wells, B.W.; Shunk, I.V. 1931. The Vegetation and Habitat Factors of the Coarser Sands of the North Carolina Coastal Plain: An Ecological Study. Ecological Monographs. 1: 465-520. |
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| Reports
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| Jordan, R.A.; Wheaton, K.S.; Weiher, W.M. 1995. Integrated Endangered Species Management Recommendations for Army Installations in the Southeastern United States: Assessment of Army-wide Management Guidelines for the Red-cockaded Woodpecker and Associated Endangered, Threatened and Candidate Species, final draft report prepared for the Natural Resources Division, USACERL. Chapel Hill, North Carolina: The Nature Conservancy, Southeast Regional Office. |
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| Kral, R. 1983. A report on some rare, threatened or endangered forest related vascular plants of the south. Atlanta, GA: U.S. Forest Service. p.718. USFS technical publication R8-TP2, . Vol. 1. |
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| Obee, E.M. 1994. Element Stewardship Abstract for Corema conradii. Trenton: State of New Jersey; Department of Environmental Protection. p.10. TNC Stewardship Abstract. 018. |
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| TNC. 1993. Rare and endangered plant survey and natural area inventory of Fort Bragg and Camp MacKall military reservations, North Carolina. Sandhills Field Office: Final report by The Nature Conservancy. |
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This
profile was updated on
1/29/2008 |
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