Exotic Species: Sandwort Drymary

Caryophyllaceae (Pink family)

At a Glance

  • Perennial
  • Spreading herb
  • Linear, opposite leaves
  • White flowers are solitary in the leaf axils.
  • Fruit is an egg-shaped capsule.
Sandwort drymary plant with several small white flowers
Sandwort drymary is a spreading, perennial herb that can be as long as 8 inches.

© Wynn Anderson (CC BY-NC-SA 3.0)

Habitat and Ecology

Sandwort drymary (Drymaria arenarioides), also known as alfombrilla, is native to northwestern Mexico, but it has been reported within a few miles of the U.S. border. It grows best in acid, sandy soils and tends to spread into dry areas and stressed rangelands. In general, it is well adapted to similar soils and climates as grama (Bouteloua) and three-awn (Aristida) grass communities. Because it grows profusely in the early spring and late fall, when warm season grasses are dormant, sandwort drymary can out-compete native vegetation. Sandwort drymary is highly toxic for cattle, sheep, and goats, and it has caused severe damage to the cattle industry in Chihuahua, Mexico.


Opening fruit capsule against a gray background and beside a scale showing it to be about 4-5mm
The fruit is a capsule that opens at maturity.

Julia Scher, US DA APHIS PPQ, Bugwood.org

Sandwort drymary is a spreading, perennial herb that can be as long as 8 inches. It has a long, slender taproot, and it reproduces by seeds.

The leaves are opposite and have smooth margins. They are linear and 0.2 to 0.6 inches long, gradually becoming smaller towards the top of the stem.

Flowers and Fruits
The flowers are white with five petals that are each 0.15 to 0.25 inches long. The petals have six to eight lobes. The flowers occur individually in the spaces between the leaf and the stem.

The fruit is an egg-shaped capsule (a dry fruit composed of more than one carpel that opens at maturity) with 15 to 25 seeds. Each seed is shaped like a ”C,” but with the ends touching.

Similar Species

Sandwort drymary is closely related to inkweed (Drymaria pachyphylla), which is found from western Texas to southeastern Arizona.


Duke, J. A. 1961. Preliminary revision of the genus Drymaria. Annals of the Missouri Botanical Garden 48(3): 173-268.

Sanchez-Munoz, A., H. L. Morton, Gonzalez, M. H., Hull, H. M., and J. Jabalera-Ramos. 1978. Ecology of Alfombrilla. Proceedings of the First International Rangeland Congress: 370-372.

Scher, J. Drymaria arenarioides. In Federal Noxious Weed Disseminules of the U. S. Available at http://keys.lucidcentral.org/keys/FNW/FNW%20seeds/html/fact%20sheets/Drymaria%20arenarioides.htm.


Prepared by Kelly Reeves, Southern Colorado Plateau Network Inventory and Monitoring Program, 2010.

Download PDF

Last updated: May 3, 2016