CPC Plant Profile: Tweedy's Sand-verbena
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Plant Profile

Tweedy's Sand-verbena (Abronia ammophila)

  • Global Rank: G1 - Critically Imperiled
  • Legal Status: N/A
  • Family: Nyctaginaceae
  • State: WY
  • Nature Serve ID: 155919
  • Date Inducted in National Collection: 01/01/2005

Abronia ammophila, a.k.a. the Wyoming sand verbena, is an upright, multi-branched perennial herb that is a member of the Nyctaginaceae family. It was first collected at the mouth of Pelican Creek along the north shoreline of Yellowstone Lake in 1885 by Frank Tweedy, and later named by Greene. Sticky glands cover the plant, except the corolla, causing the plant to be covered in sand. Leaf blades are succulent, oval to diamond-shaped, 1-2.5 cm long, and 0.6-1.5 c m wide. It starts flowering in the middle of June, and continues to bloom into September (or until the first frost), producing 15-35 greenish-white flowers subtended by membranous bracts (Galloway 1975, Greene 1900, Heidel 2007, Tweedy 1886, and Anderson and Harmon 2002). A. ammophila was a Category 2 candidate for listing under the Endangered Species Act in 1993. However, the U.S. Fish and Wildlife Service excluded this category in 1996 (USFW 1993 and 1996).

Participating Institutions
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  • 07/29/2020
  • Reproductive Research

Saunders and Sipes (2004) conducted ecological studies of pollination and reproductive systems of Abronia ammophila in 2003.

  • 07/29/2020
  • Seed Collection

A. ammophila seed was collected by the Denver Botanic Gardens in 2005 and is stored in the National Center for Genetic Resources Preservation in Fort Collins, Colorado.

Nature Serve Biotics
  • 05/02/2017

Endemic to Yellowstone National Park, Wyoming. Intrinsically rare. Some habitat has probably been lost to development of campground and recreational facilities on Yellowstone Lake.

Akiko Okawado
  • 01/01/2010

Threats include small population size, limited distribution, thermal activity and recreational use in this species' habitat or in the immediate vicinity of the plants (Heidel 2007 and Anderson & Harmon 2002). Almost all individuals are concentrated i

Akiko Okawado
  • 01/01/2010

The total estimated population was 8325 individual plants in 1998 (Anderson and Harmon 2002), with 96% of the population found in a single large colony at Mary Bay (Heidel 2007).

Akiko Okawado
  • 01/01/2010

- A. ammphila seed was collected by the Denver Botanic Gardens in 2005 and is stored in the National Center for Genetic Resources Preservation in Fort Collins, Colorado. - Saunders and Sipes (2004) conducted ecological studies of pollination and reproductive systems of Abronia ammophila in 2003.

Akiko Okawado
  • 01/01/2010

All known occurrences of this species are protected in Yellowstone National Park.

Akiko Okawado
  • 01/01/2010

Research needs involve all aspects of this species' ecology and life history.

Akiko Okawado
  • 01/01/2010

Not Available


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Taxon Abronia ammophila
Authority Greene
Family Nyctaginaceae
CPC Number 15422
ITIS 184206
Common Names Tweedy's Sand-verbena | Yellowstone sand verbena | Wyoming sand verbena
Associated Scientific Names Abronia ammophila | Abronia fendleri | Abronia arenaria | Abronia cheradophila | Abronia nelsonii
Distribution Wyoming Sand verbena is found only at Yellowstone Lake in Yellowstone National Park (Galloway 1975).
State Rank
State State Rank
Wyoming S1

This species is found on open, sandy, sparsely vegetated lakeshores within 40 meters of the shoreline. These open habitats might be maintained by erosion and fluctuation in water level (Anderson and Harmon 2002). Elev. 2,300-2,500 m. (Galloway 2003). A. ammophila is associated with Phacelia hastate, Rumex venosus, Polemonium pulcherrimum, and Lupinus argenteus (Heidel 2007).

Ecological Relationships

A. ammophila has the ability to cross- or self-pollinate. This attribute may be a factor in limiting inbreeding depression from the intrinsically small population. The main pollinators appear to be Noctuidae (noctuid moths) and Sphingidae (hawk moths). Butterflies (Lepidoptera) and bumblebees (Hymenoptera: Apidae: Bombus) may also be important pollinators for this species (Saunders and Sipes 2004).

Common Name Name in Text Association Type Source InteractionID
Bumble bees Bombus fernaldae Floral Visitor Link
Bumble bees Bombus mixtus Floral Visitor Link
Bumble bees Bombus sylvicola Floral Visitor Link
Butterflies & Moths
Brush-footed butterflies Aglais milberti Floral Visitor Link
Noctuid moths Autographa pseudogamma Floral Visitor Link
Noctuid moths Copablepharon viridispara Floral Visitor Link
Blues Glaucopsyche lygdamus Floral Visitor Link
Noctuid moths Hada sutrina Floral Visitor Link
Sphinx moths Hyles lineata Floral Visitor Link
Noctuid moths Papestra quadrata Floral Visitor Link
Brush-footed butterflies Polygonia faunus Floral Visitor Link
Whites Pontia occidentalis Floral Visitor Link
Lead Institution State Reintroduction Type Year of First Outplanting

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