The reddish-pink leaves on the left are black oak. The V-shaped tree in front is a valley oak, covered in lace lichen, denuded by oak moths. These represent two different California oak evolutionary lineages. Hybrids are common within a lineage, but not across lineages; these oaks cannot hybridize. The black oak is in the red oak (or "black oak") lineage (subgenus Erythrobalanus), with the coast live oak. The valley oak is in the white oak lineage (subgenus Lepidoalanus), along with the blue and leather oaks. Note that evergreen and deciduous (both drought deciduous and winter deciduous) oaks are in each lineage. The third evolutionary lineage, intermediate oaks (subgenus Protoblanus), has one rare representative at JRBP: the canyon live or maul oak (Q. chrysolepis). (Source: Pavlik et al, Oaks of California, Cachuma Press & California Oak Foundation,1991.)