Oxypolis rigidior (L.)

TABLE OF CONTENTS
Common Names/Synonyms
Taxonomy
Identification
Geography
Natural History
How to Encounter
Additional Information
References

Photograph Courtesy of University of Georgia Herbarium, Copyright 1978, Dept. of Botany, Univ. of Ga, Athens. All Rights Reserved



COMMON NAMES

Rigid Cowbane, Stiff Cowbane, Common Water Dropwort, Hog Fennel

SYNONYMS

Oenanthe ambigua Nutt.
Oxypolis longifolia (Pursg) Small
Oxypolis rigidior (L.) var. ambigua (Nutt.) B.L. Rob.
Oxypolis rigidior (L.) var. longifolia (Pursh) Britton
Oxypolis turgida Small



TAXONOMY

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida or Dicotyledenae
Order: Apiales
Family: Apiaceae or Umbelliferae
Subfamily: Apioideae
Genus: Oxypolis
Species: rigidior (L.)

Wisconsin Vascular Plants (http://www.ies.wisc.edu/scripts/herbarium/detail.asp?SpCode=OXYRIG)



IDENTIFICATION

Oxypolis rigidior:

    A perennial herb with an erect stem reaching to heights of six feet. Its leaves are alternately arranged in a pinnate formation of seven to thirteen leaflets. The venation is also pinnate in form. The leaves may be up to five inches long and two inches wide. They are pointed at the tip and taper to the base where they are attached to the primary stem without stalks. Oxypolis rigidior is distinguished by its coarsely serrated leaves, sometimes having zero to three teeth on each leaflet.
    The flowers are considered inflorescences, more specifically termed "umbels" hence the alternate family name Umbelliferae. The characteristic umbel consists of individual flower pedicels (stalks) that originate from a common point on the peduncle (ray). These are all different lengths that raise the single flowers to the same height, forming a level, flat-topped, densely packed umbel. These are white in color. Oxypolis rigidior has five sepals, five petals, and five stamens. Its blooming season is July to September. The fruits of this herb are elliptical and flattened in shape with lateral wings.

 Click here for another example of Oxypolis rigidior

    ". . . leaves simply pinnate, the larger ones with 3-15 narrowly obovate, oblong or lanceolate subcoriaceous coarsely 3-several-toothed or entire leaflets 2.5-15 cm. long and 0.4-4 cm. broad; leading umbel 0.6-1.6 dm. broad, without primary involucre or with only 1-few slender bracts; fruits ellipsoid to ovoid, more than half as thick as broad, 3-7 mm. long, the wings about as broad as the coarsely ribbed body; oil tubes mostly slender . . ." (Woodland, 1977)

 Here is a web page demonstrating a structural example of Oxypolis rigidior and its fruit.

Authority:

    Several authorities were observed, depending on the search of the synonym used. These were Carl Linnaeus, Coulter and Rose, Small, B.L. Rob., and Nutt. No information could be found about the holotype and paratype of this herb.

Identification Keys:

Key to Taxa Determined by Characteristics of Leaves
7a. Leaves reduces to modified or hollow, septate petioles, 12.
    12a. Stem filiform creeping; umbels simple; plant of brackish or saline mud flats...21.Lilaeopsis
    12b. Stems erect or ascending; umbels compound; stems thick; leaves represented by cross
    septate phyllodes, 1-2 dm. long..........................................................................27.Oxypolis
Key to Taxa Determined by Characteristics of Leaflets
26a. Leaflets 5 or more, 29.
    29a. Flowers yellow, leaflets broadly ovate, oblong to obvate, toothed, lobed, or coarsely
    serrate...............................................................................................................29.Pastinaca
 26b. Flowers white, leaflets lanceolate to linear, (ovate in 35), serrate, or sometimes with cleft, 30.
    30a. Leaflets entire or with five or fewer teeth on each edge; umbel without primary involucre;
    fruits flattened, without prominent ribs..................................................................27.Oxypolis

                                                        (Fernald, 1950)


GEOGRAPHY

Found in the Eastern United States including: Alabama, Arkansas, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Mississippi, Missouri, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia, Wisconsin.

 Click for a link to a map showing the distribution of Oxypolis rigidior in the United States

 Can't believe it? Well, here's another map for you.

Oxypolis rigidior (L.)


AREA
STATUS
REFERENCES
North America
Continental United States
& Canada
Eastern Regions
 Woodland, 1997
Eastern North America
United States East of Mississippi;
Ontario and Eastern Canada
yes
 Woodland, 1997
Southeastern United States
AL AR DC DE FL GA KY MD NC SC
TN VA WV
yes
 Woodland, 1997
Southern Appalachian States
AL GA KY MD NC SC TN VA WV
yes
 Woodland, 1997
Coastal Plain
yes
 http://www.npwrc.usgs.gov/resource/othrdata
/PLNTGUID/species/oxyprigi.htm
Piedmont
possible
 no specifics available
Blue Ridge Mountains
possible
 no specifics available 
Great Smoky Mountains National Park
possible
 no specifics available 
Ridge and Valley
possible
  no specifics available
Cumberland Plateau
unknown
 unknown
Georgia
yes
 http://plants.usda.gov
Clarke County, GA
yes
UGA Herbarium



NATURAL HISTORY

Habitat:
    Oxypolis rigidior prefers to grow in moist to wet soil. It is sturdy and can withstand full sunlight to moderate shade. It is a  perennial herbaceous plant.

Life Cycle: Perennial

Reproduction: Sexual

Corbon Dioxide Fixation: C3

Population Dynamics: Unknown



HOW TO ENCOUNTER

    Oxypolis rigidior can be found in bogs, swamps, wet woods, and damp rocks (Woodland, 1997). It prefers to grow in or near streams, wet prairies, and wet meadows.



ADDITIONAL INFORMATION

    Roots and leaves are poisonous.
    Contact with all parts of the plant may cause dermatitis.



REFERENCES

Brown, M.L. & R.G. Duncan. 1984. Herbaceous Plants of Maryland. Port City Press, Inc. Baltimore                         Maryland. 299-300.

Fernald, M.L. 1950. Gray's Manual of Botany-Eighth Edition. American Book Company. USA. 692-694.

Frohne, D. & H.J. Pfander. 1983. A Colour Atlas of Poisonous Plants. Wolfe Publishing Ltd. Germany.

Heywood, V.H. et al. 1978. Flowering Plants of the World. Mayflower Books, Inc. New York, NY. 219-221.

Hickey, M. & C. King. 1997. Common Families of Flowering Plants. Cambridge University Press. Cambridge, United Kingdom. 106-107

Woodland, D.W. 1997. Contemporary Plant Systematics-Second Edition. Andrews University Press. Berrien Springs, Michigan. 1102.

http://www.csdl.tamu.edu/FLORA/Apiaceae/AP0040.JPG

http://www.fs.fed.us/ne/delaware/ilpin/2059.co

http://www.ies.wisc.edu/scripts/herbarium/detail.asp?SpCode=OXYRIG

http://www.npwrc.usgs.gov/resource/othrdata/PLNTGUID/species/oxyprigi.htm

USDA, NRCS 1997. The PLANTS database. (http://plants.usda.gov). National Plant Data Center, Baton Rouge,     LA70874-4490 USA.

This page was prepared by Stephanie P. Gamble
 sgamble@arches.uga.edu
Biology/Microbiology Major
University of Georgia
Institute of Ecology
June 7, 1999