If you buy a desk for $25 an it appraises for $500, you don't have taxable reportable gain. You have an increased Worth. Your basis still is $25. If you "trade" it for a service, you and that other person just agreed on the FMV of the two items: non-cash for service of the same value. This is just like the trailer example I used previously on this forum: If you bought a $30,000 trailer for $10,000, you have a $10,000 Asset and not a $30,000 Asset. If it truly was "worth" $30,000 then why didn't you pay $30,000 for it?

@sharonbretStill hasn't identified where is the "missing" value that you seem to determine is Income?

Try thinking through it like this: You have basis and not generating the gain by selling it first, means the gain is still invested in the stock. When you donate the stock, you just donated basis + gain, inclusive. You have Unrealized Gain, so you didn't get the benefit of "touching" the gain first, so you have No Income to report. You gave appreciated stock and you gave both parts of its value: Basis + gain = FMV.