My sources show Co C, 8th Va Inf as the Evergreen Guards (first known as Bull Run Rangers), Prince William County; enlisted 5/8/1861, for 1 year; reorganized 4/26/1862
Captains: Edmund Berekeley [to Major 1863], Robert Horner Tyler

I have no listings for "Morgan Guard" although the 89th Va Militia may have been referred to as such, as they were out of Morgan County (west) Virginia, with companies A to K, all listed by the Captain's name.

Confederate Military Land Units by W.J. Tancig
A Guide to Virginia Military Organizations, 1861-1865 byLee A. Wallace, Jr.