Toxic Weed: Catsear

The plant is native to Europe, but has also been introduced to the
Americas, Japan, Australia and New Zealand.  The plant is also known as false dandelion, as it is commonly mistaken for true dandelions. Both plants carry similar flowers which form windborne seeds. However, catsear flowering stems are forked and solid, whereas dandelions possess unforked stems that are hollow. Both plants have a rosette of leaves and a central taproot. The leaves of dandelions are jagged in appearance, whereas those of catsear are more lobe-shaped and hairy. Both plants have similar uses.

Catsear is considered a noxious weed in pastures and lawn. Currently it is only classified as noxious - not toxic or harmful for livestock. However, Hypochaeris (presumably this species) is suspected of causing stringhalt in horses if consumed in excess.  Stringhalt Is a sudden flexion of one or both hind legs in the horse. It is most easily seen while horse is walking, or trotting. Best while backing up slowly, turning on affected leg, or suddenly frightened. It involves one or both hind limbs. It is a spasmatic contraction of the lateral extensor tendons of the hind legs