https://www.inaturalist.org/observations/48989713 by @lagoondon

They all may have fuzzy leaves resembling the ears of America’s favorite pack animal, but the group of plants commonly known as “mule’s ears” belong to at least 3 different genera, with multiple species, only one of which is native to San Diego County. Southern Mule’s Ears (Agnorhiza ovata) is found in our upper foothills and mountains.

They are conspicuous, but not common. The herbarium at the San Diego Natural History Museum holds only 53 voucher specimens of this species collected from our county. Observations from San Diego County of this species on iNaturalist which have been verified by Jon Rebman total only 46.

All too often observations of Southern Mule’s Ears are incorrectly identified as Woolly Mule’s Ears (Wyethia mollis) on iNaturalist. Unfortunately, when photos of Southern Mule’s Ears are uploaded to iNat, Wyethia mollis usually appears as the top suggestion given by iNat’s computer vision model. (Agnorhiza ovata did not appear in the list of suggested species at all when I tested the system with multiple photos of Southern Mule’s Ears probably because of the small number of observations of the plant.) Young leaves of both plants are typically fuzzy or woolly making it easy to be led astray by the “Woolly Mule’s Ears” common name of the top computer vision suggestion. The issue is compounded by the fact that Agnorhiza ovata is still listed under its synonym, Wyethia ovata, by several sources, including Jepson eFlora and Checklist of Vascular Plants of San Diego County, so that Wyethia mollis may “sound right” even though it is not.

Wyethia mollis is found in the central Sierra Nevada Mountains and farther north, not in Southern California. In addition to distributional range, the plants have other differences. The flower heads of A. ovata are smaller with fewer ray flowers compared to W. mollis. In general, the leaves of A. ovata are ovate and have a distinct petiole; W. mollis’s leaves are lanceolate and may not have a distinct petiole. Agnorhiza ovata lacks basal leaves, while W. mollis has more basal leaves than cauline (distributed along the stem) leaves. The outer phyllaries of A. ovata are leaf-like but those of W. mollis are narrow and barely, if at all, leaf-like.

Our local species of mule’s ears is assigned to a genus that was apparently given its name from the Greek agnostos (unknown) and rhiza (root), due to initial uncertainty about the plants’ roots. Despite its name, don’t be agnostic when you identify mule’s ears! Be confident that mule’s ears observed in San Diego County are Agnorhiza ovata.