Rubus ulmifolius Santa Cruz County

Both the revised Jepson Manual and Flora North America Vol. 9 treat several non-native blackberries for California which are not fully documented, including R. allegheniensis Porter (p. 35): “...introduced in British Columbia and California, where rare and in at least California, probably no more than a waif.” and Rubus ulmifolius Schott “found primarily in coastal California from the San Francisco Bay region southward.”

Plants that match R. ulmifolius occur in Santa Cruz County, along the upper tidewater reach of Moran Lake.  These plants are unarmed, the canes without any prickles, and would diagnose to R. u. ssp. anoplothyrsus Sudre. (synonym var. inermis).

Diagnosis: stems somewhat pruinose, NO prickles; lower leaf surface not white-pubescent

There are no CCH specimens for Santa Cruz County or Monterey County (these are my #21516, Jan 28 2015).

Overall, based on the distribution given in FNA Vol. 9, there are possibly several other non-native Rubus lurking in California, apomitic microspecies aside.    They are, relative to their invasive potential, understudied here.

Growth Habit

Lower Leaf Surface

Upper Leaf Surface