Yellow adder's tongue, or Erythronium americanum, is a species of flowering plant that is native to North America. This vibrant yellow spring wildflower is often used in gardening and landscaping due to its striking appearance. However, if you are searching for synonyms for the phrase "yellow adder's tongue," it may be helpful to consider descriptive words and phrases that evoke a similar image. For example, you could use terms like "golden lily," "sunny daffodil," "canary flower," or "buttercup bloom." Each of these alternatives captures the bright, cheerful essence of the yellow adder's tongue and could serve as an excellent substitute depending on the context of your writing.