purpletop tridens (Tridens flavus)
SCIENTIFIC SYNONYMS: There are no scientific synonyms for
TAXONOMY: The currently accepted scientific name for purpletop
tridens is Tridens flavus (L.) Hitchc.
NATIVE STATUS: Native, United States; Introduced, Canada.
GENERAL BOTANICAL CHARACTERISTICS: Purpletop tridens is
a bunchgrass with erect tufted culms. It is 35 to 75 inches tall. Leaf blades
are flat, often less than 1/2 inch wide and 10 to 27 inches long, lax, smooth,
and glossy green. The leaf sheath is flattened near the base, keeled (has a
central rib), and overlapping. The ligule (projection up from inside leaf
sheath where sheath meets blade) is a ring of short hairs. The seedhead is
an open cluster, 8 to 14 inches long, spreading, pyramid shaped, usually
purple, sometimes nearly black. The seedheads droop and are covered with
an oily or grease-like substance. There are 465,000 seeds per pound.
REGENERATION PROCESS: Purpletop tridens propagates itself by
reseeding. Purpletop seedlings are slow to develop and competition from
weeds and/or cool season grass may overwhelm the stand on the better
HABITAT TYPES: Habitats include woodland openings, savannas,
woodland borders, meadows in wooded areas, powerline clearances in
wooded areas, limestone glades, fields, roadsides, and areas along rail-
roads. Areas with a history of disturbance are preferred.
SITE CHARACTERISTICS: Purpletop tidens is adapted to soils that
are well- drained to droughty, shallow and rocky, fertile to sterile. Purple-
top tridens prefers partial to full sun, moist to dry-mesic conditions, and
soil containing loam or clay-loam. It is tolerant of road salt and often col-
onizes roadside sites, especially in Pennsylvania and south.
SEASONAL DEVELOPMENT: The blooming period occurs from mid-
summer to early autumn, lasting about 1-2 weeks for a colony of plants.
GENERAL DISTRIBUTION: Purpletop tridens is adapted to areas of
the eastern United States with more than 30 inches of rainfall, from Maine
to eastern Nebraska to eastern Texas to Florida. It is not common in north-
ern New England or New York, especially on inland sites, where poor
winter hardiness is a problem.
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 purpletop tridens has not been determined.
IMPORTANCES AND USES: Purpletop tridens is a perennial, warm
season grass that is consumed by all grazing livestock. It is well adapted
to shallow, droughty, infertile soil and provides forage in the summer and
on sites where cool season forages do not produce well. It can be planted
alone or in mixes with other warm season grasses. When not actively cul-
tivated, purpletop tridens can become a weed of hay fields, pastures, aban-
doned fields and roadsides.
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Sky Meadows Park
Crooked Run Valley