While looking through the CP database, I came to Sarracenia x 'Evendine'. Looking at its description, it claims the standard is missing. I was sure I'd seen a photo of it in a book, and sure enough, there is a photo of it on page 176 of Adrian Slack's 'Carnivorous Plants'. It is also accompanied by a caption that gives a much more detailed description than is on the CP database. Is this not valid for some reason, or was it just not noticed when listing Slack's cultivars?
Doesn't look like it. The real thing starts of green before turning red, with little white colouration.
Don't get too hung up on it though. Some of Slack's cultivars weren't exactly special in my opinion. Pioneering yes, but the wider range of plants in circulation now make for more attractive and special cultivars in my view.