Heteroecus sanctaeclarae, also known as the mushroom gall wasp (because it looks like a toadstool cottage in a children's book about woodland creatures), is a species of cynipid wasp that induces galls on huckleberry oaks and canyon live oaks on the Pacific coast of North America.

[1][2] It has also been called the steeple gall wasp because the tops of the galls look like the onion domes of Eastern Orthodox churches.

[3] The larval chamber lies in the bottom section at the seam between the two sections of the gall.

[1] According to gallformers.org, the bud galls induced by this wasp come in many colors, including beige, grey, pink, purple, and white.

[4] This species may have first been described in 1911 by David T. Fullaway as Callirhytis sanctae-clarae.