deertongue (Dichanthelium clandestinum)
Panicum clandestinum L.
TAXONOMY: The current accepted scientific name for deertongue
is Dichanthelium clandestinum (L.) Gould.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS: This perennial
grass is 1½-4½' tall. The culms are unbranched during the vernal phase
of their development, while during the autumnal phase of their develop-
ment they branch occasionally. The culms are light green, terete, and
glabrous (or nearly so). Alternate leaves occur along each culm; they
are ascending to widely spreading. The leaf blades are 2-10" long and
½-1½" (12-40 mm.) across; they are narrowly lanceolate, flat, and
smooth along their margins, except near the culms, where the lower
margins of the leaf blades are often ciliate. The upper blade surface is
yellowish green, medium green, or dark green and lacking significant
hairs, while the lower surface is similar, except it is a more pale shade
of green. The bases of the blades clasp their culms. The leaf sheaths are
light green or yellowish green, longitudinally veined, and either hairless
or hairy; the upper sheaths are especially likely to be hairy. Each vernal
culm terminates in a panicle of spikelets about 2½-6" long that is exerted
from the uppermost sheath; this panicle has a pyramidal shape with a cen-
tral rachis and ascending to widely spreading lateral branches. At inter-
vals along the rachis, these lateral branches are whorled. The branches
divide into branchlets or pedicels that terminate in solitary spikelets. The
rachis, branches, branchlets, and pedicels of the panicle are light green,
slender, and slightly wiry. Individual spikelets are 2.5-3.0 mm. long,
about one-half as much across, ovoid or broadly ellipsoid in shape, hair-
less to sparsely pubescent, and light green to greenish purple. Each spike-
let consists of 2 glumes, 2 lemmas (one fertile and the other sterile), and
a perfect floret with 2 feathery stigmata and 3 stamens. The smaller glume
is only one-third the length of the spikelet, while the larger glume and ster-
ile lemma are the same length as the spikelet. Both outer sides of each
spikelet, consisting of the larger glume and sterile lemma, have about 7 longitudinal nerves. For the vernal culm, the blooming period occurs from
early to mid-summer for about 1-2 weeks. The florets are cross-pollinated
by the wind. Afterwards, each culm continues to branch, developing se-
condary culms in its autumnal form. This causes each plant to become tall-
er. The autumnal culms and their leaves have the same characteristics as
the vernal culm and its leaves, except several panicles of spikelets are pro-
duced that remain inserted within their sheaths (and thus they are hidden
from view). Compared to the vernal panicle, these autumnal panicles are
reduced in size and they are cleistogamous (self-pollinating). Both vernal
and autumnal spikelets produce grains about 2.0-2.5 mm. long that are
ovoid and slightly flattened. After hard frost kills the autumnal culms and
their leaves, they are replaced by low winter rosettes of basal leaves. The
root system is fibrous and rhizomatous. Colonies of clonal plants are of-
ten produced from the rhizomes.
REGENERATION PROCESS: Deertongue propogates itself by reseed-
vegetative spread (rhizomes).
HABITAT TYPES: Habitats include moist depressions in rocky upland
woodlands, sandy woodlands, sandy savannas, sand prairies, acidic gravel-
ly seeps, sandy swamps, low areas along streams and ponds, and abandon-
ed sandy fields. This grass is more common in moist sandy habitats than
elsewhere and it tolerates some disturbance.
SITE CHARACTERISTICS: Deertongue prefers partial sun, moist
conditions, and sandy soil. In some situations, this grass can spread ag-
gressively via its rhizomes.
SEASONAL DEVELOPMENT: For the vernal culm, the blooming per-
iod occurs from early to mid-summer for about 1-2 weeks.
GENERAL DISTRIBUTION: Deertongue is naturally found throughout
the eastern United States and Canada, from Florida to the Maritime Provin-
ces of Canada (except New Brunswick and Newfoundland), east to Texas
north to the lower Plains States. It also occurs in Quebec and Ontario, Can-
SKY MEADOWS DISTRIBUTION:
Grass specimens can be found on trails marked in red.
Appalachian Trail/Old Trail
South Ridge/North Ridge
Rolling Meadows/ Lost Mountain
The specific distribution of deertongue has not been determined.
IMPORTANCES AND USES: Insects that feed on deertongue grass and
other panic grasses (Dichanthelium spp., Panicum spp.) include the cater-
pillars of Polites themistocles (tawny-edged skipper) and other skippers,
the larvae of such moths as Idioglossa miraculosa and Cycloplasis panici-
foliella, the leaf beetle Chalepus bicolor, Sphenophorus callosus (southern
corn billbug), Oebalus pugnax (rice stink bug), the stilt bug Jalysus spin-
osus, the plant bugs Collaria meilleurii and Collaria oculata, Anoecia
cornicola (white-banded dogwood aphid) and other aphids, the leafhoppers Polyamia herbida and Polyamia rossi, and Arphia sulfurea (sulfur-winged grasshopper). Among vertebrate animals, the seeds of panic grasses are an important source of food to many birds, especially sparrows. The seeds are
also consumed by some small rodents, such as the wild house mouse and
prairie deer mouse. The young foliage is palatable to many mammalian herbivores, including cattle, horses, sheep, deer, and rabbits.
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