Give latin name. Is it a true broom?

I don't think there is a Latin name beyond Candidatus spp.. It's a phytoplasma caused growth aberration that is many axilary breaks from a single growth/leaf axil.
Witches Broom is fairly common in plant pathology literature, most often as a symptom of phytoplasmas (that used to be called MLOs, Micoplasma Like Organisms. Asters Yellows is a common one.)
The link below is a good intro to what some of the phytoplasma caused symptoms look like.

Here is a link that might be useful: Good intro to phytoplasmas

I haven't seen any recently, but I did run into that down home a few years ago. For those that aren't familiar, here are some pics.

Here's an article that gives more information about these for anyone interested.

Here is a link that might be useful: Witches' Brooms in Celtis (a.k.a. Hackberry)

BTW what is the easiest way to differentiate the Northern and Southern (Sugarberry) species? Smoother trunk? Smaller leaves? From what I have gathered, there seems to be both in the valley. If I am correct in my identification, Sugarberry is slightly more common that Northern.