The first appearance of this strain was in Dutch smartshops. It was available as a fresh mushroom shortly after the dead of Terrence McKenna. We belief this strain was named after Terrence McKenna in order to honor him. This could be a marketing trick from the smartshops, but still it's very honorable to name a strain after Terrence Mckenna.
The following info is according to the website of one of our sponsors, which offers this strain as a Growkit:
"The McKennaii might be even stronger than the popular but difficult to grow Hawaiian (Copelandia cyanescens). No doubt the McKennaii is the strongest cubensis in our catalog. This one is for the more visually interested. Dark brown caps with an odd shape and thick sturdy stems."
Also this info could be part of the marketing trick!

source - www.fsre.nl