Panicum abscissum - Swallen
Cut-throat Grass
Other English Common Names: Cut-throat Panicgrass
Other Common Names: cutthroat grass
Synonym(s): Coleataenia abscissa (Swallen) LeBlond
Taxonomic Status: Accepted
Unique Identifier: ELEMENT_GLOBAL.2.131929
Element Code: PMPOA4K010
Informal Taxonomy: Plants, Vascular - Flowering Plants - Grass Family
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Monocotyledoneae Cyperales Poaceae Panicum
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Concept Reference
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: Panicum abscissum
Taxonomic Comments: As presented here, Kartesz (1994) treats Panicum abscissum as a distinct species, while FNA vol. 25 (2003) treats it as a subspecies of P. rigidulum (P. rigitulum ssp. abcissum).
Conservation Status

NatureServe Status

Global Status: G3
Global Status Last Reviewed: 03Dec1998
Global Status Last Changed: 23Jun1999
Rounded Global Status: G3 - Vulnerable
Reasons: This grass is very site-specific and has a narrow current range. The Florida Natural Areas Inventory currently has 54 occurrence records from Osceola, Polk, Highlands, and Palm Beach counties in its database. Historically, the species was much more widespread; the dramatic decrease in its range can be attributed to agricultural and silvicultural activities, fire exclusion, grazing, drainage, excessive site preparation, and soil disturbance.
Nation: United States
National Status: N3

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 Florida (S3)

Other Statuses

NatureServe Global Conservation Status Factors

Range Extent Comments: Panicum abscissum is restricted to five counties in central Florida. The occurrence reported from Walton County in the Florida panhandle is incorrect.

Number of Occurrences: 21 - 80
Number of Occurrences Comments: 54 element occurrences as of 12/98; however, this number is somewhat misleading because many of the 32 occurrences on Avon Park Air Force Range should be merged.

Population Size Comments: Some large stands in seepage areas on the Central Ridge slopes.

Overall Threat Impact Comments: Threats to cutthroat grass include fire exclusion, drainage, excessive site preparation and soil disturbance such as fire suppression activities, off-road vehicle use, and foraging by feral pigs, and extirpation for other land uses - habitat use for agriculture/pasture and silviculture. Habitat not considered wetland under state environmental protection regulations.

Short-term Trend: Decline of 10-30%
Short-term Trend Comments: Declining due to conversion of habitat.

Intrinsic Vulnerability Comments: Has been grazed without damaging impacts on populations in this area for years.

Other NatureServe Conservation Status Information

Global Range: Panicum abscissum is restricted to five counties in central Florida. The occurrence reported from Walton County in the Florida panhandle is incorrect.

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 FL

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
FL Glades (12043), Hendry (12051), Highlands (12055), Lake (12069), Okeechobee (12093), Orange (12095), Osceola (12097), Palm Beach (12099), Polk (12105)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
03 Upper St. Johns (03080101)+, Oklawaha (03080102)+, Kissimmee (03090101)+, Western Okeechobee Inflow (03090103)+, Caloosahatchee (03090205)+, Florida Southeast Coast (03090206)+, Peace (03100101)+, Withlacoochee (03100208)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Basic Description: A robust rhizomatous, perennial grass, growing 50-70 cm tall. Leaf blades are 15-25 cm long.
Technical Description: Cutthroat grass is a robust grass with culms 50-70 cm tall, densely tufted and compressed. Lower sheaths are broad and strongly keeled, crowded, 3-4 mm wide from keel to margin, truncate or extended at the summit into short, broad, obtuse auricles. Blades are 15-25 cm long, 1-2 mm wide, folded, and scabrous. Ligule is a very short membrane, scarcely 0.3 mm long. Panicles terminal and axillary, 7-15 mm long. Spikelets 2.8-3 mm long, obliquely set on the pedicels. Glumes, the first one-half to two- thirds as long as the spikelet, acute, 3-nerved, scabrous on the keel, the second and sterile lemma equal, 5-nerved. Caryopsis 2-2.3 mm long, 0.6- 0.7 mm wide, acute, pale, smooth, and shining.
Diagnostic Characteristics: Separated from other Panicum species in its range by this combination of characters (Wunderlin 1982): leaf sheaths truncate at apex, extending into broad wedge-shaped auricles; panicle branches ending at last spikelet (not extending beyond as a bristle); spikelets not warty.
Reproduction Comments: The major growth period for cutthroat grass occurs in March, April, May, and early June. Some growth during winter months is common, and low January temperatures of 20-25 degrees F frequently fail to produce frost damage.

Cutthroat grass blooms profusely the same summer after a growing season burn (mid-April to late July). Dormant season burns usually fail to trigger flowering, and the plant rarely flowers without fire. Cutthroat grass forms a continuous, fine, highly flammable fuel capable of carrying fire any season of the year. Some sites will reburn in less than one year. Experimental studies show that mowing and/or fertilizing also stimulate flowering, although as with fire, treatments must occur during the growing season. The viability of seed appears to be low, but seed ecology has not been fully studied. A persistent soil seed bank does not form.

Ecology Comments: The invasive capacity of cutthroat grass appears to be low. It does not appear to readily recolonize sites from where it is extirpated, even with adjacent populations present. Cutthroat grass must burn relatively frequently (1-10 years) to prevent the establishment of growth of competing shrubs and trees. Growing season burns are needed for the plants to reproduce by seed. In the absence of fire, cutthroat grass populations are readily invaded by ericaceous shrubs, gallberry, and bays. Many former cutthroat sites now support bay/gallberry vegetation. Slash pine may also invade stands of cutthroat grass. Dense slash pine with litter build-up is detrimental to the grass. If years of pine litter accumulation burns, cutthroat grass may be eliminated. However, open to moderately dense stands of slash pine with a continuous cover of cutthroat grass appear stable if burned frequently.
Habitat Comments: Grows only on moisture-receiving seepy slopes on the sandy eastern and western slopes of the Lake Wales Ridge, Florida. It may occur on small isolated slopes which receive moisture from a scrub site at higher elevation, around small seasonal ponds in scrubby flatwoods, and around depression marshes and ponds in wet flatwoods. It is frequently found in pure stands with an open slash pine overstory. Two other grass species may occur with cutthroat grass: creeping bluestem (Schizachyrium stoloniferum) and chalky bluestem (Andropogon capillipes).
Economic Attributes Not yet assessed
Management Summary
Stewardship Overview: Cutthroat grass and the seeps and glades that it dominates are threatened by fire exclusion, silvicultural and grazing practices, foraging by feral pigs, and landscape conversion. The former extent of this species within its naturally limited range has been greatly diminished.

Maintenance of protected sites will require: 1) active fire management emphasizing growing season burns, 2) limiting the impact of disruptive activities, i.e. all-terrain vehicle use, inappropriate use of fire plows, excessive mechanical site preparation, foraging by feral pigs, 3) restoration of degraded sites, and 4) monitoring of the effectiveness of management activities. Fire important to reproduction and persistence; provide land managers with information on species biology for inclusion in land management plans.

Restoration Potential: Reintroduction of burning in ecologically appropriate ways should eventually restore cutthroat grass sites that have developed into shrub and pinelands. Reintroduction potential of cutthroat grass is unknown.
Preserve Selection & Design Considerations: Preserve design must consider prescribed burning at the site, now and in the future. Upland communities must be maintained as water sources for seepage flow.
Management Requirements: This species and its associated community can only be maintained by an active and ecologically appropriate regime of prescribed fire.

Management of cutthroat grass should include frequent burns. For maintenance of cutthroat populations, this means burns every 1 to 10 years, favoring early growing season burns. For recovery of degraded populations, an initial winter burn to reduce fuel may be needed, and annual/biennial burns may be necessary to reduce shrubs. Pine density should be reduced to natural stocking levels. Growing season burns should be favored.

Monitoring Requirements: Monitoring is needed to evaluate effectiveness of long-term burn applications and recovery on degraded cutthroat grass sites.

Biological monitoring procedures should include:

1. establishing permanent photo points

2. low level aerial photography

3. line transects to determine relative cover of grass vs. shrubs.

Management Programs: Active cutthroat grass management programs exist at: - Archbold Biological Stations; contact Eric Menges, Staff Plant Ecologist - Tiger Creek Preserve; contact Geoffrey Babb, Central Florida Land Steward, The Nature Conservancy - Arbuckle State Reserve; contact Mark Hebb, Florida Div. of Forestry, Walt Thomson, Florida Division of Recreation and Parks, or Geoffrey Babb, Central Florida Land Steward, The Nature Conservancy
Monitoring Programs: There are currently three active cutthroat monitoring programs:

1. Archbold Biological Station, Highlands County, FL. Permanent transects exist in seven seasonal ponds. Long-term photopoint series and vegetation studies are underway. Cutthroat sites are under an active fire management program.

2. Arbuckle State Reserve, Polk County, FL. Florida Dept. of Natural Resources, Florida Div. of Forestry and The Nature Conservancy are planning monitoring of cutthroat grass.

3. Tiger Creek Preserve, Polk County, FL. The Nature Conservancy conducts an active fire management program. Cutthroat sites are being identified.

Management Research Programs: Archbold Biological Station/The Nature Conservancy Investigator: Ronald Myers "The effect of fire on cutthroat grass flowering phenology".
Management Research Needs: Research needs include studies of seed biology, community dynamics, and effects of silvicultural practices on cutthroat grass populations.
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 03Dec1998
NatureServe Conservation Status Factors Author: KARL BERTRAM & RONALD MYERS, TALL TIMBERS RESEARCH STATION, TALLAHASSEE, FL; rev. L.G. Chafin (12/98)
Management Information Edition Date: 03Aug1989
Element Ecology & Life History Edition Date: 03Aug1989
Element Ecology & Life History Author(s): K. BERTRAM & R. MYERS, TALL TIMBERS RES STA, TALLAHASSEE, FL 9/88, REV M.E. STOVER, TNC-HO

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).

  • Abrahamson, W.G. 1984a. Post-fire recovery of Florida Lake Wales Ridge vegetation. American J. Botany 71(1): 9-21.

  • Abrahamson, W.G. 1984b. Species response to fire on the Florida Lake Wales Ridge. American J. Botany 71(1): 35-43.

  • Asker, S.E., and L. Jerling. 1992. Apomixis in plants. CRC Press, Boca Raton, Florida. 298 pp.

  • Connor, H.E. 1979. Breeding systems in the grasses: a survey. New Zealand J. Botany 17: 547-573.

  • Fryxell, P.A. 1957. Mode of reproduction of higher plants. Botanical Review 23(3): 135-233.

  • Gleason, H.A., and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. New York Botanical Garden, Bronx, New York. 910 pp.

  • Kartesz, J. T. 1987. Unpublished plant characterization database information on vascular plant species of the U.S., Canada, and Greenland.

  • 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.

  • Kral, R. 1983c. A report on some rare, threatened, or endangered forest-related vascular plants of the South. U.S. Dept. of Agriculture Forest Service Technical Publication R8-TP2, Athens, GA. 1305 pp.

  • Martin, A.C., H.S. Zim, and A.L. Nelson. 1951. American wildlife and plants: A guide to wildlife food habits. Dover Publications, Inc., New York, NY. 500 pp.

  • Myers, R., and S. Boettcher. 1987. Flowering response of cutthroat grass (Panicum abscissum) following fire. Bull. Ecological Society America. 68: 140 (Abstract).

  • Proctor, M., and P. Yeo. 1973. The pollination of flowers. William Collins Sons & Co. Ltd, London. 418 pp.

  • Ridley, H.N. 1930. The dispersal of plants throughout the world. L. Reeve & Co., Ltd., Ashford, Kent, United Kingdom. 744 pp.

  • Weakley, A. S., R. J. LeBlond, B. A. Sorrie C. T. Witsell, L. D. Estes, K. Gandhi, K. G. Mathews, and A. Ebihara. 2011. New combinations, rank changes, and nomenclatural and taxonomic comments in the vascular flora of the southeastern United States. Journal of the Botanical Research Institute of Texas 5(2):437-455.

  • Wunderlin, R.P. 1982. Guide to the vascular plants of central Florida. Univ. Presses Florida, Gainesville. 472 pp.

  • Yarlett, L.L. August 1981. Cutthroat grass, a unique native grass. pp. 4. The Palmetto.

  • Yarlett, L.L. February 1984. Cutthroat grass. pp. 11. The Palmetto.

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