Do the roots emerge from the calluses? 

I've seen pictures of roots growing way down at the bottom of the cutting, right at the edge. 

I've also read roots come from a node, but don't they also grow along the "trunk" between nodes?

What exactly is a root initial?  "R"? - sorry, I couldn't resist LOL LOL

Yes.
Those roots are usually growing from the calluses
Yes they come from the small dots that you see at or near the nodes.
The "initials" are "Initial root" the white formations from which roots emerge.

Under the proper conditions, roots can emerge almost everywhere on the cutting. Hope this helps.

Most of my cuttings grow the roots from the very bottom edge. Some roots may grow from the nodes and even anywhere in between. I started my cuttings in cups.

Thanks!  I set up a bin, I think I will do some cups with perlite and sp moss.

JoAnn,
    If you have those initials on your cuttings, then you are real close to having actual roots at some point in the near future(the time varies from variety to variety).  Some folks plant them as soon as the initials start to show, others wait until they see actual roots(I usually wait a little, but I've heard that both methods work).  So it sounds like you are well on your way with the rooting process.  Good Luck.

You are certainly not the first to ask these questions  :)  Check this thread out, especially post 4 and on.  And also

http://en.wikipedia.org/wiki/Lenticel

I would guess that a lot of people see lenticels and think they're root initials.    You can tell the difference by letting the cutting sit in the air for a while.  When not wet the lenticels will recede (shrink) while roots wont.  Prominent lenticels are a sign the environment doesn't have enough air.

Am I wrong to think that often times roots form at the lenticels? I have always thought that when I see a swollen lenticel with hard white material (not fluff) in the center that tiny root tips would be following soon after. Maybe I just assumed it was solid and not fluff.
Great, now I am going to be poking around in the sphagnum more than I do already. I will have to limit the excessive poking to one or two cuttings.

Lenticels.....new word for today!  Nice :)

Seems like if the bottom cut is just below  a node, then roots form at the bottom, otherwise, they seem to have no clue where to form and form all over.  If I can, I try re-cut them so the cut is just below the node!

The lenticels themselves are not root forming tissues.  A root could form nearby.  Most of my roots form at the bottom of a cutting just deep to the bark.  It doesn't matter if there's a node or not there.

Bob, thank you so much for the link to that thread!  When I acquired some cuttings last June, I had not known about the signs of the growing/rooting process with the cuttings.  As a result, I thought I had a lot of white mold on the cuttings.  In hindsight I was more successful then I thought, I was ignorant.  Now, since I have more knowledge, I hope I will be successful and realize it to further the growing process.  I will make it a point to use the correct verbiage when the time comes ;)