These photos show leaves and staminate catkins of Quercus sadleriana....a very distinctive species.

This shrub-sized, evergreen oak is found in the general environs of the Klamath Mountains region of Northwestern California & Southwestern Oregon (see the BONAP county distribution map).

The somewhat thick & leathery leaves are unlike any other CA oak: large and ovate-elliptic (with no hint of lobing), with a very well-defined & regular venation pattern. There is a single mid-rib, from each side of which emanate (at an acute angle) 10 or more straight, parallel, uniformly-spaced secondary veins...each ending in a single, small (non-spinose) tooth which together form the serrate leaf margin. The species is also unusual among CA oaks in having persistent, densely long-silky stipules...which are clearly visible in the full-size versions of the images here.

It's believed that Q. sadleriana is an ancient relictual species which formerly had a much larger range but now only persists in the refugium provided by the Klamath Mountains. Studies indicate that the duo of Q. sadleriana and Q. pontica...another shrubby, evergreen, relictual species with a localized modern range in Eurasia (in the environs of Armenia)...comprise a distinct clade within Quercus. According to recent work of McVay, Hipp, & Manos(2017) there is ''unabiguous support'' for the conclusion that:

''The sister group relationship of two narrow endemics, one from the Siskiyou and Klamath Mountains of western North America (Q. sadleriana), and the other from the Caucasus Mountains (Q. pontica), forms the earliest branch of the white oaks.''