Who's on guitar for The Mamas & the Papas song 'California Dreamin'?

Who is playing guitar on the 1966 track 'California Dreamin' by The Mamas & the Papas? A common quirk of the wonderful music made in the 1960s is that the name credited on the song you're singing along with doesn't always let you know who was really playing on the record. Take The Monkees, for instance, where the four could each play their instruments, but you won't hear them playing any themselves on 'Saturday's Child' or 'I'm a Believer', or take The Byrds' debut single, 'Mr Tambourine Man', where the 12-string guitar is supplied by bandleader Roger McGuinn but none of the other instruments you can hear are being played by his fellow Byrds. Or most of the music on The Righteous Brothers' chart-topping classic 'You've Lost That Lovin' Feelin', and even 'Good Vibrations' by The Beach Boys. Actually, all of those songs, and thousands more besides, featured members of the very same backing band: The Wrecking Crew. When you consider the consistent quality of the excellent session teams and studio bands in the 1960s, whether that be The Funk Brothers at Motown or Booker T & the MGs at Stax, it's really no wonder that so much of the music being made in that magical decade was so much better than practically anything ever since. Most of the songs from the era that we still love and listen to every single day were made by the same musicians, just the frontmen and singers changed between songs. Some of those backing bands and session groups were made up of wider pools of musicians than the others, but none of them would allow anyone to join except the very best, which is evident from looking at The Wrecking Crew, which had Hal Blaine, Carol Kaye, Glen Campbell, James Burton, Leon Russell, Barney Kessell, Dr John and countless other supremely talented players among their ranks. Among the countless songs The Wrecking Crew played on was also the only number-one hit that The Mamas & the Papas ever had in the USA, 'Monday, Monday'. You can also hear various combinations of Wrecking Crew players across each of the four albums The Mamas & the Papas released in the 1960s, including Hal Blaine on drums, Larry Knechtel on the piano and Joe Osborn on the bass, on their most famous, enduring, recognisable and defining song, 'California Dreamin'. A song now so synonymous with the 1960s, and so definitive of the flower-power sound of California itself, it's the vocal harmonies of Denny Doherty, Cass Elliot and John and Michelle Phillips that stay in your head once the song has stopped, but it's that iconic guitar intro which announces the song in the first place, and so quickly sets the autumnal mood that persists throughout. If you listen closely, you can hear a rhythmic acoustic strumming coming through from one of the Papas, John Phillips, but that intro was supplied by, of course, one of The Wrecking Crew, PF Sloan. Alongside that intro, you've also heard his playing on hit songs like 'Secret Agent Man' by Johnny Rivers and 'A Must to Avoid' by Herman's Hermits, sometimes even earning co-writer credits. I guess when you've come up with a part as immortal as the 'California Dreamin' intro, you don't really need to stick around and do anything else on the rest of the song. Your work is done long before the leaves begin to brown and fall from the trees.