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Conserving and restoring
America's native plants |
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CPC National Collection Plant Profile
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Panicum hirstii
| Family: |
Poaceae (Grass Family) |
| Common Name: |
Hirst's panic grass |
| Taxon Synonyms: |
Dichanthelium hirstii, Panicum aciculare |
| Author: |
Swallen |
| Growth
Habit: |
Perennial |
| CPC
Number: |
3086 |
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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. |
Panicum hirstii
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Panicum hirstii is a stiffly erect panic grass that grows 20 - 60 cm (8 - 23 in) tall. The taxon inhabits sandy pine woods and pond shores of the coastal plain barrens of New Jersey, Delaware, and North Carolina. It is also found in limestone depression ponds and shallow Cypress ponds of Georgia. Threats to this species come mainly from habitat alteration for development and changing hydrology of coastal ponds.
Research and Management Summary:
Taxonomic work and germination studies have been performed for this species, and some monitoring of populations has occurred.
Plant Description:
Panicum hirstii grows from clustered culms. The inflorescence, or panicle, is 3-10 cm (1-4 in) long and sparsely flowered with finely hairy spikelets; panicles sometimes stay hidden among the densely branched stems. The leaf blades are 3 - 12 cm (1 - 4.7 in) long and 2 - 7 mm (0.08 - 0.3 in) wide and variably smooth or hairy.
| Distribution
& Occurrence |
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State Range
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Delaware
Georgia
New Jersey
North Carolina |
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Habitat
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Panicum hirstii occurs in sandy, coastal plain areas that undergo rises and falls in water level. Among its habitats are: coastal plain ponds in the New Jersey pine barrens; limestone depression ponds and shallow Cypress ponds in Georgia; and maritime wet grasslands of North Carolina (Amoroso 1999).
According to notes of J. R. Swallen (quoting the discoverer, Frank Hirst), the type specimen of Panicum hirstii came from a "small woodland pond in the pine barrens -- growing in the water, much as Panicum spretum often does. This is a most interesting pond, the Panicum being associated with Lobelia boykinii, Paspalum dissectum, Coreopsis rosea, etc." (Swallen 1961: 235-236). Other collections have been made in 1900 from the margin of a pine-barren pond, Sumter County (Georgia), and in 1947 from a Cypress swamp, Calhoun County (Georgia), according to Swallen (1961). |
Distribution
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Extant populations of Panicum hirstii occur in Delaware, North Carolina, and New Jersey (NatureServe 2001). Documents from the U. S. Fish and Wildlife Service listed the species as "E" (endangered) in Georgia, where it was formerly reported from two counties, Sumter and Calhoun (USDA 2001). However, the Association for Biodiversity Information and the Georgia Natural Heritage Program (2001) now list the species as "SH" (historic) in that state, as it has not been observed in Georgia in the past thirty years. |
Number Left
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One population in Delaware and two in North Carolina are known to be extant and vigorous. Populations at the New Jersey sites have declined significantly in recent years to just a few flowering stems (NatureServe 2001). The total global population is estimated at less than 1000 individual plants (NatureServe 2001). |
State/Area
Protection
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State/Area |
Rank |
Status |
Date |
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Delaware |
S1.1 |
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2/1/2001 |
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Georgia |
SH |
E |
10/1/2001 |
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New Jersey |
S1 |
E |
9/1/2001 |
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North Carolina |
S1 |
E |
1/1/1999 |
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| Conservation,
Ecology & Research |
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Ecological
Relationships
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• There is no published literature on the ecology of this taxon.
• As a member of the flora of coastal plain ponds and other seasonally wet depressions, the biology of this species is likely to be tightly tied to the variable hydrological regime that is characteristic of these areas. Population numbers fluctuate dramatically from year to year (NatureServe 2001), as is typical of the species endemic to these habitats.
• Pollination of this small-flowered grass is likely to be via wind. The species apparently can form a seed bank (NatureServe 2001). For more on the ecology of coastal plain ponds of the region, see Schneider (1994). |
Threats
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Threats are largely unknown. Populations in New Jersey have declined precipitously, but the reasons for this remain elusive. The following factors may be important but without experimentation or closer observation, they are largely speculative:
• changing hydrology of coastal plain ponds due to increasing human population density and water withdrawal
• inbreeding depression in small populations leading to increased mortality
• invasive species encroachment on pond shores and wet grasslands
• habitat conversion for development, particularly in the Pine Barrens of New Jersey
• illegal dumping |
Current Research Summary
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• Karen Bennett of the Delaware Natural Heritage Program has monitored Panicum hirstii in that state
• Taxonomic work on the species is ongoing. Although the taxon was first described as Panicum hirstii by Swallen (1961), Kartesz (1999) has placed the taxon into Dichanthelium while maintaining its distinct species epithet, a placement that accords with other research (Schuyler 1996). Richard LeBlond, Inventory Specialist with the North Carolina Natural Heritage Program is further investigating the taxonomy of the Panicoid grasses for the North Carolina flora. Writing in 1991 (unpublished), LeBlond said that the variability in characters suggest "the possibility of a topoclinal relationship between Panicum neuranthum and P. hirstii, the two diverging genetically and in habitat preference northward from Florida to New Jersey [however] the combination of wider autumnal leaves and included autumnal panicles in Dicanthelium = P. hirstii does not occur in any other Dicanthelium entity."
• The New England Wild Flower Society (Framingham, Massachusetts) has collected seeds, but despite repeated attempts, has not been able to germinate seed successfully. |
Current Management Summary
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• No information is available regarding specific management addressing Panicum hirstii. |
Research Management Needs
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• Population viability analysis for all remaining populations
• Experiments with culms grown from collected seed on how local hydrology, inundation depth, and water chemistry affect seed germination, seedling establishment, and plant reproduction.
• Analysis of genetic homozygosity levels in isolated populations |
Ex Situ Needs
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• Comprehensive seed storage and germination trials from additional populations are needed for this taxon |
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| Books (Sections)
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| Kartesz, J.T. 1999. A synonymized checklist of the vascular flora of the U.S., Canada, and Greenland. In: Kartesz, J.T.; Meacham, C.A., editors. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden. Chapel Hill, NC. |
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| Electronic Sources
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| NatureServe. (2008). NatureServe Explorer: An online encyclopedia of life [web application]. [Internet].Version 7.0. NatureServe, Arlington, Virginia. http://www.natureserve.org/explorer. Accessed: (June 17, 2008). |
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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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| Clancy, K.; McAvoy, W.; Rothstein, D.; Trew, L. 1993. Coastal Plain Ponds. Outdoor Delaware. 2, 13-17 |
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| Schuyler, A.E. 1996. Taxonomic status of Panicum hirstii Swallen. Bartonia. 59: 95-96. |
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| Swallen, J.R. 1961. A new species of Panicum from New Jersey. Rhodora. 63, 751: 235-236. |
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| Reports
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| Amoroso, J.L. 1999. Natural Heritage Program list of the rare plants of North Carolina. Raleigh, North Carolina: North Carolina Natural Heritage Program. |
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| Kral, R. 1983. A report on some rare, threatened, or endangered forest-related vascular plants of the South. Athens, GA: U.S. Dept. of Agriculture Forest Service. p.1305. U.S. Dept. of Agriculture Forest Service Technical. |
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| Patrick, T.S.; Allison, J.R.; Krakow, G.A. 1995. Protected plants of Georgia: an information manual on plants designated by the State of Georgia as endangered, threatened, rare, or unusual. Social Circle, Georgia: Georgia Department of Natural Resources, Wildlife Resources Division, Georgia Natural Heritage Program. p.218 pp + appendices. |
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| USFWS. 1991. Northeast coastal areas study: significant coastal habitats of southern New England and portions of Long Island Sound, New York. Charlestown, Rhode Island: Southern New England - Long Island Sound Coastal and Estuary Office. |
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| Theses
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| Schneider, R.L. 1994. Environmental controls of plant species diversity in coastal plain pondshore communities. [Ph.D. Thesis]: Cornell University. Ithaca, NY. |
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