Frangula californica (USA)

Rhamnus californica (syn. Frangula californica), commonly known as coffeeberry and California buckthorn, is a species of flowering plant in the family Rhamnaceae, the buckthorns. It is native to the southwestern United States and Baja California in Mexico.^[1] It is an introduced species in Hawaii.^[2]

The 1/8″ greenish flowers occur in clusters in the leaf axils, have 5 sepals, and 5 shorter petals.^[3] It blooms in May and June.^[3]  The fruit is a juicy drupe which may be green, red, or black. It is just under a centimeter long and contains two seeds that resemble coffee beans.

This shrub is a member of many plant communities and grows in many types of habitat, including chaparral, coastal sage scrub, and woodlands. It grows in forest types such as foggy coastal oak forests, redwood forests, and mountain coniferous forests. It can be found alongside chaparral whitethorn (Ceanothus leucodermis), toyon (Heteromeles arbutifolia), skunkbush (Rhus trilobata), redberry (Rhamnus crocea), and western poison oak (Toxicodendron diversilobum). In brushy mountain habitat it grows among many species of manzanita.^[4]

The plant reproduces sexually by seed and vegetatively by sprouting. After wildfire or cutting, the plant generally resprouts from its root crown. Reproduction via seed is most common in mature stands of the plant. It produces seeds by 2 or 3 years of age. Seeds are mature in the fall. Seed dispersal is often performed by birds, which are attracted to the fruit; some plants are so stripped of fruit by birds that hardly any seeds fall below the parent plant.^[4]

This long-lived plant is persistent and becomes a dominant species in many habitat types, such as coastal woods. In the absence of wildfire, the shrub can grow large, with a wide spread that can shade out other flora. When fire occurs, the plant can be very damaged but it readily resprouts from the surviving root crown, which is covered in buds for the purpose. It reaches its pre-burn size relatively quickly.^[4]

Parts of the plant, including the foliage and fruit, are food for wild animals such as mule deer, black bears, and many birds, as well as livestock.^[4]

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Cultivated Bush For ID : California : 02NOV14 : AK-4 : 5 posts by 2 authors. Attachments (2).  

Bush seen at the Golden Gate Park on 30th Sept,14.

Frangula californica (Eschsch.) A. Gray

Syn: Rhamnus californica Eschsch.

California coffeeberry in fruit, photographed from Fremont California, 18-10-2017.

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References: The Plant List Ver.1.1  GRIN  Wikipedia