Silktree, Mimosa

Albizia julibrissin

Fabaceae (Legume family)


Description

Silktree is a brittle-stemmed, short-lived tree that grows up to 40 feet tall. It is often broader than it is tall, with a flat top and an umbrella-like shape. The leaves are composed of several sets of small, pale-green leaflets on the short stems. The showy flowers are borne in clustered heads at the ends of branches. The red or pink color comes from the multitude of stamens, which extend far beyond the other parts of the flower. The flat, thin-walled, persistent seed pods measure about 0.5 to 1 inch across and 5 to 8 inches long, and contain numerous flat, brown seeds.


Habitat

Mimosa is a native of Asia and is widely planted as an ornamental across Texas. It has escaped and become naturalized primarily in the eastern third of the state.


Toxic Agent

The legume (bean) contains a neurotoxic alkaloid that is responsible for the nervous signs and is thought to act as a pyridoxine (vitamin B6) antagonist. Poisoning occurs when trees with green or mature pods are made available to cattle, sheep or dogs. They may gain access because of windfall or when trees have been pruned and the limbs with legumes are discarded where animals have access to them. The lethal dose is about 1.5 percent of an animal's body weight in green or brown legumes containing seeds.


Signs of Livestock Ingestion

Signs of poisoning occur 12 to 24 hours after intake of the legumes and include: Exaggerated response to stimuli; Muscular twitching; Labored respiration; Salivation; Convulsive seizures; Death.


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