Eryngium constancei is a species of flowering plant in the family Apiaceae known by the common name Loch Lomond button celery, or Loch Lomond coyote thistle. It is endemic to California, where it is known from only three occurrences north of the San Francisco Bay Area. One of the populations is at the Loch Lomond Vernal Pool Ecological Reserve at Loch Lomond in Lake County. The plant appears mainly in vernal pools. It is endangered on the state and federal levels.