CPC Plant Profile: Harperella
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Plant Profile

Harperella (Ptilimnium nodosum)

Harperella occurs in rocky or gravelly areas along swift-flowing streams or on the edges of ephemeral ponds along coastal plains (shown here in rocky habitat). Photo Credit: Johnny Randall
  • Global Rank: N/A
  • Legal Status: N/A
  • Family: Apiaceae
  • State: AL, AR, GA, MD, NC, SC, TVA, VA, WV
  • Nature Serve ID: 161024
  • Date Inducted in National Collection: 02/09/1992

Harperella grows along rocky shoals of clear swift-flowing streams, and requires a very narrow range of hydrologic conditions in order to survive. The water depth can't be too high nor too low and the water quality must be good. This has made the species highly vulnerable to any seemingly minor or major changes in their habitat either in the immediate vicinity of their location, or upstream from there. Because of this, half of the known populations of this species have been destroyed. The ten remaining populations are scattered across Alabama, Arkansas, Georgia, Maryland, North Carolina, South Carolina, and West Virginia where stream quality is still relatively high, and development and pollution is relatively low. (Arkansas Natural Heritage Commission 2002) This delicate wildflower grows up to three feet tall and is a member of the economically important family of plants (Apiaceae) that includes such food products as carrots, dill, and horseradish, as well as several plants with known medicinal value. The tiny white clusters of this rare species resemble those of its common relative, Queen Anne's Lace. However, where most members of its family have fern-like (highly dissected) leaves, the leaves of this species are nothing but short, hollow "quills". (Maryland Department of Natural Resources 2002)

Participating Institutions
CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.
Michael Kunz
  • 12/02/2021
  • Seed Collection

NCBG staff conducted a brief survey for Ptilimnium nodosum in NC.  The effort was to locate individuals for seed collection to update aging banked seeds and to contribute seeds to the IMLS seed longevity study.  After a couple hours of searching, we found no plants.  However, since we did not have boats or adequate ways to travel further down stream, the survey was incomplete.  Larger surveys and collection efforts will continue in 2022, as well as germinating seeds from this same population for a seed increase.

Center for Plant Conservation
  • 08/19/2021
  • Orthodox Seed Banking

In 2021, CPC contracted North Carolina Botanical Garden to recollect seed from a population currently held in long term orthodox seed storage as part of an IMLS-funded seed longevity experiment. The National Laboratory for Genetic Resources Preservation will evaluate how germination tested viability and RNA Integrity of seed lots decline over time in storage.

Nature Serve Biotics
  • 05/02/2017

Approximately 45 occurrences (24 drainages/watersheds) are believed extant in scattered localities in the southeast, mid-Atlantic, and, somewhat disjunctly, in the Ouachita Mountains of Arkansas. The largest population concentration occurs along the West Virginia/Maryland border, with a second large population concentration in Arkansas. The species is dependent on narrow hydrologic conditions and is vulnerable to alterations to the natural hydrologic regime, siltation and erosion, water quality reductions, disturbance and trampling, and, possibly, competition from invasive plants; land-use conversion is also a threat at some sites. Many of the occurrences are at least partially on federal or state lands, under a conservation easement, or managed for conservation, but, particularly for the riverine populations, protection/management of occupied sites alone may be insufficient to ensure persistence in the face of watershed-level threats. Also, of the five pond populations believed extant, only one is protected. A few of the riverine populations are large, but appear to be declining. Many historically-known sites have been lost; at least 25% of mapped occurrences are considered historical or extirpated.

  • 01/01/2010

Vulnerable to pollution of the riverine habitats where this species occurs Susceptible to changes in stream hydrology, such as draining of its habitat or areas upstream for conversion to agricultural land, or drowning of it by stream impoundments

  • 01/01/2010

Approximately 10 populations remained at the time of listing (USFWS 1988); six stream populations in Alabama, Maryland, West Virginia, and North Carolina, and four pond populations in South Carolina and Georgia. However, populations were found in five counties in Arkansas in 1990 (Arkansas Natural Heritage Commission 2002).

  • 01/01/2010

Kress et al. studied the genetic variation of this species (1994). North Carolina Botanical Garden has attempted to germinate seeds of this species, but have found them extremely difficult to germinate, possible because, like many other wetland plants, their seeds do not tolerate storage well.

  • 01/01/2010

None known.

  • 01/01/2010

Little is known about the habitat requirements of Ptilimnium nodosum, including the effects of fire and fire suppression. (USFWS 1991)

  • 01/01/2010

Continue to work on propagation protocols.


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Taxon Ptilimnium nodosum
Authority (Rose) Mathias
Family Apiaceae
CPC Number 3675
ITIS 29554
Common Names Harperella | Piedmont mock bishop-weed
Associated Scientific Names Ptilimnium nodosum | Ptilimnium fluviatile | Ptilimnium viviparum | Harperella fluviatilis | Harperella nodosa | Harperella vivipara | Ptilimnium fluviatile var. viviparum
Distribution Alabama, Arkansas, Georgia, Maryland, North Carolina, South Carolina, and West Virginia (Maryland Department of Natural Resources 2002; Arkansas Natural Heritage Commission 2002).
State Rank
State State Rank
Alabama S1
Arkansas S2
Georgia S1
Maryland S1
North Carolina S1
South Carolina S1
Tennessee Valley Authority S
Virginia S1
West Virginia S1

A wetland-dependent plant, this species occurs in two specific habitat types:1) shoals and margins of clear, swift-flowing streams2) on the coastal plan along the edges of shallow, intermittently flooded ponds and wet meadows(USFWS 1988)

Ecological Relationships

Relies on natural flooding cycles to maintain open ground for favorable habitat. Seeds disperse via water.

Common Name Name in Text Association Type Source InteractionID
insects Suspected Pollinator Floral Link
Lead Institution State Reintroduction Type Year of First Outplanting
North Carolina Botanical Garden North Carolina Reintroduction 2006
North Carolina Botanical Garden North Carolina Reintroduction 2019

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