Wright's Rosette Grass Dichanthelium wrightianum (Scribn.) Freckmann

Herbarium specimen from Florida Karen MacClendon

Herbarium specimen from Florida
Karen MacClendon

Class
Monocotyledoneae (Monocots)
Family
Poaceae (Grass Family)
State Protection
Endangered
Listed as Endangered by New York State: in imminent danger of extirpation in New York. For animals, taking, importation, transportation, or possession is prohibited, except under license or permit. For plants, removal or damage without the consent of the landowner is prohibited.
Federal Protection
Not Listed
State Conservation Status Rank
S1S2
Critically Imperiled or Imperiled in New York - Especially or very vulnerable to disappearing from New York due to rarity or other factors; typically 20 or fewer populations or locations in New York, very few individuals, very restricted range, few remaining acres (or miles of stream), and/or steep declines. More information is needed to assign either S1 or S2.
Global Conservation Status Rank
G4
Apparently Secure globally - Uncommon in the world but not rare; usually widespread, but may be rare in some parts of its range; possibly some cause for long-term concern due to declines or other factors.

Contents

  1. Summary
  2. Conservation and Management
  3. Habitat
  4. Range
  5. Identification Comments
  6. Taxonomy
  7. Additional Resources
  8. About This Guide

Summary

Did you know?

The name for the genus comes from the Greek words meaning two-flowering, and refers to the two flowering periods of these grasses, once on the primary stalk in the spring and again on the branches in late summer. This species was named for its discoverer, 19th century botanist Charles Wright (Fernald 1950). Wright collected plants from Texas for Asa Gray and has many plants named after him (Wikipedia contributors).

State Ranking Justification

There are three existing populations but the population size is only known in one of them. This population has hundreds of plants. There are four historical populations from the early 1900s and one from 1966 which have not been rediscovered although habitat still exists.

Short-term Trends

Repeated surveys have not been performed for any of the populations so short-term trends are unknown.

Long-term Trends

This plant has always been rare in New York and at very low levels where it remains today. This trend should continue into the foreseeable future.

Conservation and Management

Threats

Some ponds have seen too much development along the shoreline which threaten populations with direct disturbance by trampling and ATV use. Road runoff is also a threat to one population.

Conservation Strategies and Management Practices

The pondshores need to be protected from direct disturbance by ATVs and excessive trampling. Exotic invasive species must be prevented from colonizing the shores. A natural buffer of at least 200 feet should be established around the ponds to prevent excessive runoff and pollution events.

Habitat

Habitat

The few known occurrences for D. wrightianum in New York are from the edges of ponds or vernal ponds along the coastal plain, sometimes within pine barrens (New York Natural Heritage Program 2010). Moist, sandy or peaty areas, low pine savannahs, bogs, the margins of ponds, and cypress swamps (FNA 2003). Wet ground, beaches, and borders of ponds (Gleason and Cronquist 1991).

Associated Ecological Communities

  • Coastal plain pond shore (guide)
    The gently sloping shore of a coastal plain pond with seasonally and annually fluctuating water levels. Plants growing on the pond shore vary with water levels. In dry years when water levels are low there is often a dense growth of annual sedges, grasses, and herbs. Submerged and floating-leaved aquatic plants, such as fragrant waterlily and pondweeds, may become "stranded" on the exposed shore. In wet years when the water level is high only a few emergents and floating-leaved aquatics may be noticeable. T
  • Pine barrens vernal pond (guide)
    A seasonally fluctuating pond and its associated wetlands that typically occurs in pine barrens. The water is intermittent, usually a pond in the spring but sometimes losing water through the summer to become a mostly vegetated wetland at the end of the summer. These ponds and wetlands may be small.

Range

New York State Distribution

This grass is only known from the eastern end of Long Island.

Global Distribution

This grass occurs on the coastal plain from Massachusetts and New York south to Florida and west on the Gulf Coast of Texas. It is rare from North Carolina north to Massachusetts. It also extends south to Cuba, Mexico, Central America, and northern South America.

Identification Comments

General Description

This species is a perennial grass which forms small clumps. The erect or ascending stems are from 15 to 50 cm tall, usually hairy, and arise from a basal rosette of ovate to lance-shaped leaves. The nodes are swollen and darker than the internodes. There are 4 to 7 stem leaves, with blades 2-4.5 cm long, 2-5 mm wide, and finely hairy on the lower surface. The primary panicles are 2.5-5.5 cm long and about 1/3-2/3 as wide, and the pedicels are slightly sticky. The spikelets are only 0.8 to 1.1 mm long, the lower florets sterile, and the upper (fertile) ones 0.7 to 0.9 mm long (FNA 2003). Like other Dichanthelium species, Wright's Panic Grass produces two sets of flowers. The descriptions above refer to the primary infloresence. In the "fall phase", from July to October, the stems produce numerous new branches from the nodes. The secondary infloresence consists of panicles hidden in the leaf axils of these new branches, containing cleistogamous (hidden), self-fertilizing flowers (FNA 2003).

Best Life Stage for Proper Identification

Stems with leaves and mature fruits, preferably including both primary and secondary (late season) infloresences are needed for identification.

Similar Species

D. wrightianum is most similar in appearance to D. ensifolium and D. chamaelonche, which are southern species not found in New York (FNA 2003). It differs from its closest New York relative, Dichanthelium villosissimum var. villosissimum, by having smaller spikelets (<1.0 mm long versus 1.1 to 2.5 mm for D. villosissimum) and narrower leaves (3 to 5 mm wide versus 3 to 13) (Gleason and Cronquist 1991).

Best Time to See

The mature fruits develop and are visible from late July through October.

  • Fruiting

The time of year you would expect to find Wright's Rosette Grass fruiting in New York.

Wright's Rosette Grass Images

Taxonomy

Wright's Rosette Grass
Dichanthelium wrightianum (Scribn.) Freckmann

  • Kingdom Plantae
    • Phylum Anthophyta
      • Class Monocotyledoneae (Monocots)
        • Order Cyperales
          • Family Poaceae (Grass Family)

Additional Common Names

  • Panic Grass
  • Wright's Panic Grass

Synonyms

  • Panicum wrightianum Scribn.

Additional Resources

References

Fernald, M. L. 1950. Gray's manual of botany. 8th edition. Corrected printing (1970). D. Van Nostrand Company, New York. 1632 pp.

Flora of North America Editorial Committee. 2003. Flora of North America, North of Mexico. Volume 25. Magnoliophyta: Commelinidae (in part): Poaceae, part 2. Oxford University Press, New York. 783 pp.

Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.

Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.

New York Natural Heritage Program. 2010. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.

New York Natural Heritage Program. 2023. New York Natural Heritage Program Databases. Albany, NY.

Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://newyork.plantatlas.usf.edu/, Albany, New York

Links

About This Guide

This guide was authored by: Stephen M. Young

Information for this guide was last updated on: September 20, 2012

Please cite this page as:
New York Natural Heritage Program. 2023. Online Conservation Guide for Dichanthelium wrightianum. Available from: https://guides.nynhp.org/wrights-panic-grass/. Accessed June 6, 2023.

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