[G]orse seedlings [transplanted] from a vacant lot in Daly City to our greenhouse [developed] abnormal growth: continued production of juvenile leaves and stunted shoot tips with reduced, thickened scale leaves or even clublike apices. Examination of the shoot tips revealed colonies of eriophyoid mites living among the appressed leaves. These mites were [initially identified as Aceria genistae but research published nearly 20 years after this paper appeared has established that they belong to the related species, Aceria davidmansoni.] ... The mite’s damage to gorse and French broom in Daly City appears to be negligible and is often inconspicuous. [The authors speculate that greenhouse conditions may have produced greater damage than occurred in the field ...

a complex of cryptic Aceria species [is] associated with the brooms and gorse ... the mites from U[lex] europaeus and G[enista] monspessulana in California, USA, previously misidentified as A[ceria] genistae ... are in fact A. davidmansoni. In both cases, A. davidmansoni can be clearly distinguished from A. genistae qualitatively by the pattern on the prodorsal shield and quantitatively by several characters such as the number of annuli on the hysterosoma ...