Leaf Inkweed, Thickleaf Drymary (Drymaria pachyphylla) Description Inkweed is a glabrous, short-lived annual with blunt pointed leaves that are usually about as wide as they are long. The plant grows close to the ground in a circular pattern eight to ten inches in diameter. Small flowers are produced in the axils of the leaves. Distribution and Habitat Inkweed grows on sites with sparse vegetation, most commonly on heavy, alkaline clay soils and in low areas subject to occasional flooding. The plant is usually not locally abundant except on disturbed sites. It is typically found in western Texas, southern New Mexico, west to southeastern Arizona, and south into Mexico. Regions: 10. Toxic Agent Cattle, sheep and goats are known to be poisoned by this plant. The actual toxic agent contained in inkweed is unknown. Both dry and green plants are toxic as well as all parts of the plant. Most poisoning occurs on overgrazed ranges and plants are most commonly grazed in the early part of the day while they are turgid. The period between the onset of symptoms and death is unusually brief and is characteristic of drymary poisoning. Due to this, symptoms are not easily observed under range conditions. Feeding experiments have shown that 0.6% of the body weight of the plant will kill a sheep, 0.4% a cow and 0.9 percent a goat. Symptoms appeared 18-24 hours after ingestion of a toxic dose.

Livestock Symptoms Animals poisoned by inkweed usually die before symptoms are noticed. Death usually occurs less than two hours after the first symptoms occur. Symptoms in the order of their occurrence are as follows: loss of appetite diarrhea arched back and "tucked up" abdomen coma death Integrated Management Strategies Inkweed is very unpalatable to all classes of livestock. Poisoning generally occurs only when other forage is limiting. As such, range management practices that promote improved range conditions and increased diversity of forage will be beneficial in reducing loss of livestock to inkweed. Special caution should be observed during drought years. Printable Version (PDF)