Buckthorn and California coffee

Buckthorn noun - A shrub or shrubby tree of the genus Rhamnus; fruits are source of yellow dyes or pigments.

California coffee and buckthorn are semantically related. In some cases you can replace phrase "California coffee" with "Buckthorn", this terms are similar.

California coffee noun - Evergreen shrub of western United States bearing small red or black fruits.

Buckthorn and California coffee are semantically related. You can use "Buckthorn" instead a noun phrase "California coffee".