Inkweed, Thickleaf Drymary

Drymaria pachyphylla



Inkweed is a smooth, hairless, short-lived annual with bluntpointed, circular leaves usually about as wide as they are long. The plant grows close to the ground in a circular pattern 5 to 10 inches in diameter. Small flowers are produced in the leaf axils.


Inkweed grows on sites with sparse vegetation, most often on heavy, alkaline clay soils and in low areas subject to occasional flooding. It is generally not locally abundant except on disturbed sites. Inkweed is found in western Texas, southern New Mexico, west to southeastern Arizona and south into Mexico.

Toxic Agent

The plant poisons cattle, sheep and goats. Its toxic agent is unknown. All parts of dry and green plants are toxic. Most poisoning occurs on overgrazed ranges. Plants are most often grazed in the early part of the day when they are swollen with water and more upright. Feeding experiments have shown that a lethal dose is 0.6 percent of body weight for a sheep; 0.4 percent for a cow and 0.9 percent for a goat.

Signs of Livestock Ingestion

Signs appear 18 to 24 hours after a toxic dose is ingested. Death usually occurs less than 2 hours after the first clinical signs occur. Signs appear in this order: Loss of appetite; Diarrhea; Arched back and tucked up abdomen; Coma; Death.

Management Strategies

Inkweed is very unpalatable to all classes of livestock. Poisoning generally occurs only when other forage is limited. Range management practices that improve range conditions and increase forage diversity help reduce losses to inkweed. Take special caution in drought years.