Castilleja ambigua is a species of Indian paintbrush known by the common name Johnny-nip. It is native to western North America from British Columbia to California, where it is most common along the coast in salt marshes and scrub. This is a highly variable annual herb growing to a maximum height near 30 centimeters. The leaves are 1 to 5 centimeters long and lobed or not. The inflorescence is up to 12 centimeters long and a few wide. It is packed with bracts that have white to light purple ridged tips. Between the bracts emerge the lobed flowers, which are yellow to light purple or rose. The fruit is a capsule about a centimeter long. This is a highly variable annual herb growing to a maximum height near 30 centimeters. The leaves are 1 to 5 centimeters long and lobed or not. The inflorescence is up to 12 centimeters long and a few wide. It is packed with bracts that have white to light purple ridged tips. Between the bracts emerge the lobed flowers, which are yellow to light purple or rose. The fruit is a capsule about a centimeter long. Subspecies. There are three subspecies, two of which are endemic to California. The Humboldt Bay owl's clover, Castilleja ambigua ssp. humboldtiensis, is considered a threatened plant in Northern California.