Several cuttings showing variation in leaf shape and color. These are probably all ssp. californica though some show significant white on the bottom of the leaves.
Bottom left, 'Slender Curls' from Gray Whale Cove are narrow and curved in/cupped and dark-topped like 'Leatherleaf', bottom right from Montara Mountain. This same cupped leaf shows up south west of the summit of San Bruno.
'Mound San Bruno typically has neat little leaves and is one of the most compact selections. This same form grows on Bayview Hill, San Francisco and Sweeny Ridge.
'Eve Case, bottom center is white underneath with deep veination. You won't see the white underneath without turning it over. Eve Case is the off-spring of 'Seaview', a ground cover sized coffeeberry from Skyline near Crystal Springs with small leaves.
Middle-right, 'Acuminata' has deep veination like Eve Case and tapered pointy tips which point up and look like chinquapin leaves. Bright green underneath.
Top left are tomentose selections from San Bruno Mountain. Some fade to dark green as the leaves get older.
Abridged note from Jepson:
"Frangula californica grows throughout most of California and the subspecies are somewhat separated geographically, but intermediates and variants in California exist between almost all the subspecies.
In California, ssp. ursina occurs only in San Bernardino Co.,
ssp. californica is the most coastal, growing from the western Klamath Mountains south to Agua Tibia Mtn in southern California.,
ssp. occidentalis is characteristic of mafic and ultramafic substrates in northwest California; plants on other substrates approach ssp. californica, but leaf blades are equally green (not yellow-green) on both surfaces.
Wolf reported that "from San Francisco Bay region to Santa Barbara Co. is a form of Rhamnus californica in which the leaves are whitened beneath, but upon examination show pubescence much shorter than that in Rhamnus tomentella. In older leaves it often disappears. This form is very abundant".
Plants in Los Angeles and Orange counties have leaf blades with sparse (not dense) tomentum and a few long hairs beneath as in ssp. cuspidata.
Intermediates between ssp. crassifolia and ssp. tomentella are rare in northern California,
but many plants in San Diego Co. "have leaves narrowly to broadly elliptical and many would pass for ssp. crassifolia in the Inner Coast Range." He considered these plants variants of ssp. tomentella.
Some plants in southern Oregon vary in leaves from those of ssp. occidentalis.
The Frangula californica complex needs study using modern techniques."