Arctostaphylos myrtifolia is a species in the Ericaceae (Heath) family known by the common name Ione Manzanita. It is a rare species, endemic to the Sierra Nevada foothills of California where it grows in the chaparral and woodland on a distinctive acidic soil series in western Amador and Calaveras Counties. This is a red-barked, bristly shrub reaching just over a meter in maximum height. The small bright green leaves are coated in tiny hairy hairs and are shiny but rough in texture. They are less than 2 centimeters long. The flower cluster is a raceme of urn-shaped manzanita flowers on bright red branches. The fruit is a cylindrical drupe only a few millimeters long. A major threat to this rare endemic plant is a pair of fungal diseases. A branch canker caused by species of Fusicoccum, including F. aesculi, causes some mortality, and root and crown rot caused by Phytophthora cinnamomi has destroyed entire stands of the manzanita and prevented its regrowth in patches of infested soil.