Well, I don't know Grays views on race in detail, but I'd guess they were decidedly liberal. He was a strong opponent of the scientific racism of the day (e.g. Josiah Knott, Samuel Morton, Louis Agassiz, etc) although this may have been because he saw these works as apologies for slavery. Gray was a very passionate abolitionist (as was Darwin). Their shared glee at the start of the Civil War -- which both immediately saw as a war against slavery, long before Lincoln came to see it so -- was almost unseemly.
As an abolitionist, Gray was most certainly a Republican.
The parting of the ways with Gray would have come over the relevant passages to race in Descent.
You surmise incorrectly again. Gray reviewed Descent favorably, and their friendship and correspondence continued through the rest of their lives.
Interesting to note also that Fiske includes a very extensive list of those who he felt contributed to the understanding of Darwin's theory in that age, and that Asa Gray is nowhere mentioned.
An odd oversight on Fiske's part. Gray reviewed all of Darwin's books prominently and favorably, led the debate against Darwin's primary opponent in America, Louis Agassiz, incorporated evolutionary theory deeply into his own botanical studies, and wrote one of the more widely read popular books on evolution: Darwiniana: Essays and Reviews Pertaining to Darwinism (1876).
It would be interesting to see if Gray ever taught anything on Darwin, but I doubt it.
You're batting a thousand. Gray not only taught evolution to his own students, and probably before anyone else in America did so, but he also was also the first to include evolution in textbooks. (Gray's botany textbooks and manuals, written for both children and adults, were far and away the most popular and successful of the late 19th Century.)
The work of Darwin only really begins to show up after the Civil War
Uh, DUH! The Americans were a tad preoccupied with slaughtering each other.
Asa Gray is more likely in the ID camp, which is the in the line of Newton's clockwork universe, where the maker builds it, winds it up and walks a way. Not found in Fiske
Did you even read that ASA article I linked for you? Gray's views were similar to Fiske's, in viewing design as due to ongoing supervention by God of the smallest details of nature, in contrast to Darwin's view that design -- if it existed at all -- was only to be found in "general laws".
Yet you call Fiske eccentric, but not Gray. In any case, their viewpoint came after the origin of intelligent design and makes God imminent in the world. You took great delight in thinking you were countering that argument while you documented my point precisely which that it was not an odd or hardly accepted viewpoint.
If you ever get around to reading some more Darwin, you will yet find he thought so too.
Nice work
Asa Gray: American Botanist, Friend of Darwin by A. Hunter Dupree
It's usefully read in conjunction with: