Las Pilitas Nursery has it right!

I have quoted this before, but it continues to be by far the best thing I have read on how "new" oak "species" and "varieties" get named.  It's on the web site of Las Pilitas Nursery in Santa Margarita, CA.  The best part is now I'm only a half away from them, and definitely hope to visit the nursery soon!

Quercus dumosa is the most messed -with tree in the state. The botanists have divided up the species into all sorts of forms, most of which exist on the hillsides of both nurseries. McMinn said it in 1939 “Several varieties of this species have been described, but the characters used in attempting to distingish them fail when specimens collected throughout the range of this polymorphic species are examined.” Amen.

Double amen.  Then again, McMinn is also the dude who, in 1949 along with partners in crime Babcock and Righter, "discovered" Quercus x chasei McMinn, Babcock and Righter (Q. agrifolia x kelloggii), a hybrid that had already been "discovered" many miles to the south in 1944 and named Quercus x ganderi C.B. Wolf... so ol' McMinn didn't do much to simplify things.  Pot/kettle/black.  This is a common theme in oak taxonomy: When someone else tries to split a population into a new species or variety, they are "splitters" out to make a name for him/herself and in the process causes unwarranted complication.  When you split a population into a new species or variety yor are bringing specificity and clarity to bear on the situation, and those who disagree with your are "lumpers" who aren't smart enough to discern the subtle differences that are so clear to you.

It seems that every few years a budding botanist blunders out of his or her ivory tower and discovers that there are bushy oaks outside. Now these oaks do not key in the floras easily (keying is wandering through a flora's (a book) selection process that is supposed to be based primarily on reproductive parts of the plant). So, Mister or Ms. hot shot botanist writes a paper describing his or her “new” oak. Every time a 'new' oak is described it leads to more confusion and more 'new' oaks. These oaks below should probably all be considered various forms of Scrub Oak ( Quercus dumosa).
Quercus Xacutidens
Quercus berberidifolia- new name for Q. dumosa, given to new plants that are supposed to only occur in San Diego but are elsewhere. The landscape trade only recognizes old Q. dumosa, so in the name of 'restoration' the gene pool is being replanted with oaks from all over the state.
Quercus cornelius-mulleri (Very much like Q. john tuckeri or Q. xalvordiana. A wonderfully clean beautiful small tree. I actually figured this one out once.)
Quercus dumosa var. elegantula
Quercus durata var. gabrielensis (let's see you separate Q.durata from Q. dumosa by leaf roll, and this form has no leaf roll; maybe it's Q. dumosa?)
Quercus grandidentata (Q. engelmannii X Q. dumosa)
Quercus xhowellii (Q. dumosa X Q. garryana)
Q. john tuckeri (Q. turbinella var. californica) probably was originally a hybrid between Q. douglasii and Q. dumosa
Quercus X kinselae (Q. dumosa X Q. lobata)
Quercus X macdonaldii (Q. dumosa X Q. lobata)
Quercus X townei (Q. dumosa X Q. lobata)
Quercus dumosa var. turbinella
AND, the live oaks have dwarf forms that can also mimic Quercus dumosa.

I absolutely love this passage (especially the "budding botanist blunders..." part).  It's dripping enough sarcasm to water Las Pilitas Nursery for a week, and it sums up the situation with oak taxonomy perfectly.  Exactly the same could be said for the Southeast, and (in spades) for the Big Bend region of Texas. 

Three separate names for Q. dumosa x Q. lobata!  Sheesh, I really have my work cut out for me trying to key out the oaks of my (latest) adopted state.

Continuum, people.  Oaks falls on a continuum, not into isolated, unrelated groups.
About which much more soon...