Pineland Threeawn

Description from Ladybird Johnson Wildflower Center Native Plant Database.

Florida Forest Plants


Wiregrass (Aristida stricta)

Wiregrass, also called pineland threeawn, is one of the most common grasses in the southern pine flatwoods and upland sandhills.

It is a favorite food of gopher tortoises and quail and provides valuable cover for many birds, reptiles, and small mammals. The young plants may also be used as a forage by livestock.

This is a fast growing species that regenerates quickly after fires. The plant depends on regular summer burning in order to stimulate flowering and seed production.

Wiregrass is often confused with a similar plant, piney woods dropseed (Sporobolus junceus), which also has long, thin, wiry leaves. However, wiregrass has small tufts of hair at the leaf base; the dropseed stems are smooth and hairless.

Wiregrass is limited to the southeastern United States. It ranges from Mississippi to Florida but only as far north as South Carolina.



Identifying Characteristics
Size/Form: Wiregrass is a perennial bunch grass that grows in dense, spreading tufts, reaching heights of 1½' to 3'.
Leaves: The leaves are long, thin, wiry, or needle-like with tufts of fine, white fuzz around the leaf base. Margins are rolled inward.
Flowers: Wiregrass flowers are tiny and close to the flower stalk with 3 distinct hair-like awns protruding from each flower.
Fruit: The fruit is a tiny, yellowish grain (seed).
Habitat: Wiregrass grows prolifically in flatwoods and dry sandhills. It is a common understory cover in longleaf pine forests and on newly burned sites.

More info for the terms: hardwood, litter

Clewell [8] speculates that decadent pineland threeawn clumps growing
beneath young hardwood stands may be susceptible to fire. Under these
circumstances, pineland threeawn may be killed because burning of the
deep accumulations of hardwood leaf litter could raise soil temperatures
around the apical meristems to a lethal level.

pineland threeawn
wiregrass

More info for the terms: cool-season, formation

Pineland threeawn is a native, densely tufted, cool-season, perennial
bunchgrass. It grows in large clumps that are up to 6 inches (15 cm)
across at the base. Hundreds of stiff but flexible leaves arise from
each clump. The narrow leaves are strongly inrolled, resembling a fine
wire, and may attain lengths of 20 inches (0.5 m) [8]. Most leaves die
within 1 year of their formation but are persistant; thus plants contain
much dead material [31]. Seedstalks are rare and occur only after fire.
They are about 3 feet (1 m) tall, erect, with a spikelike terminal
panicle about 12 inches (30 cm) long [14].

Plants produce tillers with no rhizomes, except for populations in south
Florida, which are rhizomatous [31]. Pineland threeawn is extremely
shallow-rooted and is easily pulled or dug from the ground. Most roots
are within 8 inches (20 cm) of the soil surface, and no roots grow
deeper than 18 inches (46 cm) [31].

Pineland threeawn grows on the Atlantic coastal plain from southeastern
North Carolina to southern Florida, and westward to Mississippi [8].

More info for the terms: fire regime, litter, natural

Plant adaptations to fire: Pineland threeawn is a fire-adapted species.
Its meristems are located about 1 to 1.5 inches (3 cm) below the soil
surface, where they are insulated from the heat of fire [23,31]. Fire
in Southeastern savannas and grasslands generally raises soil
temperatures very little because the flaming front passes quickly.
During prescribed fires in wiregrass stands in Florida, soil
temperatures 0.13 inch (0.2 cm) below the soil surface seldom exceeded
120 degrees Fahrenheit (50 deg C) [31]. Thus, meristems are located
deeply enough that fire seldom or never subjects them to lethal
temperatures. Following fire, the surviving meristems quickly initiate
new top-growth. New leaf blades commonly emerge within 3 days after
fire [25].

Fire ecology: In general, pineland threeawn litter builds up quickly,
decomposes slowly, and is highly flammable. Without fire, aboveground
biomass peaks in just 3 or 4 years, resulting in a dense "wiregrass
rough" [31]. In presettlement times, this was one of the primary fuels
to sustain lightning-caused fires in Coastal Plain savannas. The
natural fire regime was one of frequent, low-intensity, summer surface
fires. Christensen [6] estimated that Coastal Plain savannas burned
every 2 to 8 years. Clewell [8] estimated presettlement fire
frequencies in longleaf pine savannas at 2 to 4 years.

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".

More info for the terms: cover, fire exclusion, fire-free interval, fuel, herbaceous, prescribed fire

Cattle grazing considerations: Prescribed fire is used to increase the
nutritional quality of pineland threeeawn. In general, protein content
and digestibility increase significantly, but return to preburn levels
within 2 or 3 months. When pineland threeawn was burned in January or
February in Georgia, protein content on March 15 was 10 percent on
burned sites, but only 3 percent on unburned sites. By June 10, protein
content of burned and unburned plants was similar at 4.2 and 4 percent,
respectively [16]. Without periodic burning pineland threeawn
hearbaceous yeilds decline rapidly. After 6 to 8 years without fire,
herbaceous yields are reduced by 50 percent [26]. Season of burning
greatly affects short-term yields. Pineland threeawn produced two and
four times as much herbage 60 days after burning when burned in May or
March, respectively, as compared with burns in October or November [25].
Hughes [40] suggests that grazing should be deferred following burning
until pineland threeawn grows 6 to 8 inches (15-20 cm) tall.

Effects of fire suppression: Pineland threeawn becomes decadent after
just 8 to 10 years without fire [17]. After 10 to 20 years of fire
exclusion, many clumps become dormant and inconspicuous [8]. On the
Alapaha Experimental Range in Georgia, cover was reduced from 12 to 1
percent after a fire-free interval of 21 years [17]. However, plants
that have survived fire exclusion in a decadent or dormant state for
decades are rejuvenated and grow vigorously after fire [8].

Fuel buildup: Within 3 or 4 years after fire, a steady state of
aboveground biomass is reached in pineland threeawn stands, which may
equal 5,500 to 7,000 pounds per acre (6,200-7,800 kg/ha). About 70
percent of this is mulch [31]. Pineland threeawn-dominated stands
produce enough fuel to burn annually [16]. Prescribed fire on a 2-year
rotation is carried out in south Florida flatwoods dominated by pineland
threeawn [12,40].

More info on this topic.

More info for the term: geophyte

Geophyte

More info for the term: association

Pineland threeawn is the principal grass of longleaf and slash pine
savannas and flatwoods [8,31]. It also grows on dry sandhills in
association with turkey oak (Quercus laevis), in scrubby flatwoods and
dry prairies, and in seasonally wet grass-sedge bogs, where it grows on
elevated tussocks [2,8].

Soils and soil moisture: Most pineland threeawn habitats are
characterized by relatively infertile sands and sandy loams [8]. The
soils of longleaf pine-pineland threeawn savannas are often psammaquods
or sandy ground water podzols [5]. These soils are typically composed
of over 90 percent fine sand with the water table ranging between 20 and
40 inches (50-100 cm) below the soil surface [5]. Pineland threeawn
tolerates seasonal flooding, but does not survive on sites where the
water table is within 2 inches (5 cm) of the soil surface year-round
[8].

More info on this topic.

This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

More info for the term: hardwood

69 Sand pine
70 Longleaf pine
71 Longleaf pine - scrub oak
83 Longleaf pine - slash pine
84 Slash pine
85 Slash pine - hardwood
98 Pond pine
111 South Florida slash pine

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

FRES12 Longleaf - slash pine
FRES13 Loblolly - shortleaf pine
FRES14 Oak - pine

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the term: forest

K111 Oak - hickory - pine forest
K112 Southern mixed forest
K114 Pocosin
K115 Sand pine scrub
K116 Subtropical pine forest

The fibrous composition, abundance, and high percentage of dead leaves
make pineland threeawn highly flammable [8]. Burning pineland threeawn
stands at any time of the year tends to remove all aboveground biomass,
leaving only a thin layer of ash on the soil [5,31].

Pineland threeawn provides primary cattle forage in recently burned pine
flatwoods in Florida and Georgia [14]. Following burning, it is grazed
primarily in the spring, after which cattle shift to other grasses such
as bluestems (Andropogon spp.) and panicums (Panicum spp.) [27,37]. In
areas not burned for 2 or 3 years, cattle do not graze pineland threeawn
because of large accumulations of dead material [14].

More info for the terms: cover, herbaceous, shrub, shrubs, swamp, xeric

Pineland threeawn is the dominant grass cover in xeric longleaf pine
(Pinus palustris) savannas and nearly all slash pine (P. elliottii)
flatwoods [7,8]. It is also a major component of many grass-sedge
(Carex spp.)-pitcher plant (Sarracenia spp.) bogs [8].

Associates: Common herbaceous associates include Curtis dropseed
(Sporobolus curtissii), toothachegrass (Ctenium aromaticum), lovegrass
(Eragrostis spp.), bluestems, beak rush (Rhynchospora spp.), bottlebrush
threeawn (Aristida spikiformis), and panicums. Shrub associates include
saw palmetto (Serenoa repens), gallberry (Ilex glabra), fetterbush
(Lyonia lucida), scrub oaks (Quercus spp.), and ericaceous shrubs
[2,20,23].

Published classifications that describe pineland threeawn community
types include:

Plant communities of the Coastal Plain and their succesional
relationships [39]
The phytosociology of the Green Swamp, North Carolina [20].

More info for the term: graminoid

Graminoid

More info for the term: seed

Timber/Soil/Ecosystem Management: To reduce competing vegetation and
facilitate easy planting of pines, mechanical site preparation is a
common management practice following timber harvest in pine savannas and
flatwoods. Chopping or disking, which is most common, nearly eliminates
pineland threeawn because it has shallow roots. These practices have
destroyed thousands of acres of pineland threeawn annually, promoting
growth of weedy grasses. Once removed from a site, pineland threeawn
does not reestablished, even after several decades, because of
negligible seed production [2,8,30].

Grazing: Pineland threeawn increases slowly on areas burned annually
and grazed year-round. It decreases in areas grazed heavily in spring
and left ungrazed during summer and fall [22].

More info for the term: fire management

Mature pineland threeawn is a low quality forage. Compared with other
native forage grasses, it is poorly digested and nutritionally inferior
[18,27]. Nutritional quality is greatly increased by prescribed burning
[see Fire Management Considerations].

AL FL GA MS NC SC

On unburned range, pineland threeawn is largely unpalatable to grazing
animals. New growth is tender and nutritious, and highly palatable for
about 6 weeks [8,14].

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Growth begins in January in south Florida, and in March in Georgia.
Leaf blades grow 6 to 8 inches (15-20 cm) in 4 weeks [22]. Flowering in
Florida typically occurs from July through September [31], and from
September through November in the Carolinas [33].

More info for the terms: cover, prescribed fire

Vegetative growth: Following fire, pineland threeawn quickly initiates
new top-growth from undamaged underground regenerative structures. The
leaves grow rapidly, and preburn cover is regained within a few months.
In southern Florida, pineland threeawn grew to a height of 8.6 to 9.4
inches (22-24 cm) 30 days after burning in March and May. Sixty days
after burning, plant heights were 10 inches (25 cm) on March burns, and
12.6 inches (32 cm) on May burns [40].

Flowering: Season of burning greatly affects pineland threeawn's
flowering response. In Florida, it responds vegetatively with little or
no flowering following dormant-season burns, but flowers vigorously
following burning in May, June, or July [1,25]. Platts and others [32]
found that following summer burning, 78.5 percent of pineland threeawn
tillers produced flowering culms, but only 5.9 percent produced
flowering culms following dormant season burns. Season of burning
appears to be less important in North Carolina. Prescribed fire in a
longleaf pine savanna in late February resulted in 94 percent of
pineland threeawn plants flowering [5]. Throughout pineland threeawn's
range, fire-stimulated flowering is short lived. No flowering occurs
during the second fall after fire [31].

Tussock graminoid

More info for the terms: natural, seed

Pineland threeawn sexual reproduction is extremely rare. Plants flower
in the summer or fall only if defoliation (i.e., fire, grazing, mowing)
has occurred within the previous 9 months. Season and type of
defoliation greatly affect flowering vigor. In general, late spring or
summer burning results in the most vigorous flowering, and sometimes
abundant seed production [5,31]. Plants may flower following fire at
other times of the year, but seeds are rarely formed.

Seedling establishment is poor. Because of high optimum germination
temperatures (85-95 degrees Fahrenheit [30-35 deg C]) and after-ripening
requirements, germination cannot begin until the growing season after
dispersal [8,31]. In the long interum between dispersal and
germination, seeds are susceptible to destruction by fungi and seed
predators, resulting in scant natural germination [8]. In the
laboratory, germination has varied greatly from 2 to 97 percent [31],
and 20 to 25 percent [36].

Vegetative regeneration: Following disturbance which removes top-growth,
pineland threeawn initiates new growth from underground meristems [8].
Vegetative expansion is slow and complicated. As the central portion of
older and larger clumps die, the clump becomes doughnut-shaped. As the
clump expands the doughnut-shaped clump fragments, forming many small
clumps, each of which have the potential to expand and form a doughnut
of their own [8].

More info on this topic.

More info for the terms: fire exclusion, hardwood, shrubs

Facultative Seral Species

Pineland threeawn dominates fire-maintained southeastern grasslands and
savannas. These communities are probably best described successionally
as "fire-maintained sub-climax or climax" [31]. In the absence of
frequent fire, hardwood trees and shrubs, especially saw palmetto and
gallberry, quickly invade and dominate savanna understories. At the
Tall Timbers Research Station in Florida, hardwoods begin to dominate
savanna understories after just 4 to 8 years of fire exclusion [7].
Pineland threeawn is somewhat shade tolerant. It can persist in the
shade of invading hardwoods for 20 to 40 years, but is eliminated if
fire does not occur after that time [8].

The currently accepted scientific name of pineland threeawn is Aristida
stricta Michx. [33]. There are no recognized subspecies or varieties.

More info for the terms: natural, restoration, seed

Longleaf pine/pineland threeawn ecosystems have been reduced by as much
as 98 percent since presettlement times and are considered endangered
[30]. Pineland threeawn establishment is essential for restoration of
these ecosystems, yet little is known about pineland threeawn
propagation [9]. Research has shown that pineland threeawn can be
regenerated from seed collected in natural stands 5 to 8 months after
summer burning [36]. This suggests that pineland threeawn can be
reestablished by direct seeding or by transplanting container-grown
material.

Perennials, Terrestrial, not aquatic, Rhizomes present, Stems nodes swollen or brittle, Stems erect or ascending, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes solid or spongy, Stems with inflorescence less than 1 m tall, Stems with inflorescence 1-2 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades very narrow or filiform, less than 2 mm wide, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Leaf blades more or less hairy, Ligule present, Ligule a fringe of hairs, Inflorescence terminal, Inflorescence an open panicle, openly paniculate, branches spreading, Inflorescence a contracted panicle, narrowly paniculate, branches appressed or ascending, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence with 2-10 branches, Flowers bisexual, Spikelets pedicellate, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets solitary at rachis nodes, Sp ikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating above the glumes, glumes persistent, Spikelets disarticulating beneath or between the florets, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes distinctly unequal, Glumes equal to or longer than adjacent lemma, Glumes awned, awn 1-5 mm or longer, Glumes 1 nerved, Lemma coriaceous, firmer or thicker in texture than the glumes, Lemma 3 nerved, Lemma glabrous, Lemma apex acute or acuminate, Lemma distinctly awned, more than 2-3 mm, Lemma with 3 awns, Lemma awns about equal in length, Lemma awn less than 1 cm long, Lemma awn 1-2 cm long, Lemma awned from tip, Lemma margins inrolled, tightly covering palea and caryopsis, Lemma straight, Callus or base of lemma evidently hairy, Callus hairs shorter than lemma, Palea present, well developed, Palea membranous, hyaline, Palea shorter than lemma, Palea 2 nerved or 2 keeled, Stamens 3, Styl es 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.

Aristida stricta is a warm-season grass, native to North America, that dominates understory vegetation in sandhills and flatwoods coastal plain ecosystems of the Carolinas in the Southeastern United States. It is known as wiregrass (due to its texture) and pineland three-awn grass.

Its common name, wiregrass, gave rise to the naming of the Wiregrass Region in which it is located.

This is a fast-growing species that regenerates quickly after fires. The plant depends on regular summer burning in order to stimulate flowering and seed production.