The sweet pea and Lathyrus species information site
The Origin of the Spencer Sweet Pea
The mutation which gave rise to the large flowered English Spencer sweet peas seems to have occurred simultaneously in two or three locations. Most famous of these was at Althorp House, seat of the Spencer family, where the gardener, Silas Cole, named the new variety 'Countess Spencer'. It is now generally accepted that this occurred as a sport of the popular Eckford variety 'Prima Donna'.
Cole's own account, however, was very different. It is worth remembering that the work of Gregor Mendel was virtually unknown at his time, and so the implausibility of Cole's account would not have been apparent. It would seem likely that Cole was trying to protect the commercial potential of his new variety by publishing a misleading version of its origin.
“Being very fond of sweet peas, I turned my attention to them in 1898. That summer I crossed the variety Lovely with Triumph, saved the seed and the following year 1899 there were two or three promising seedlings, the rest being rubbish. The good ones I crossed with Prima Donna and the next season that was 1900 there was one plant among the seedlings much stronger than any of the other varieties. That proved to be the original Countess Spencer. I just managed to save five seeds - one pod only. The following spring, after sowing them, I lost three of them in one night through mice. The stock was then reduced to two plants but from them I saved 90 seeds. It was from these plants I exhibited at the old Royal Aquarium for the first time. In 1902 I sowed all the seeds, every one came true but owing to it being a wet summer I only managed to save 3,000 seeds. 2,200 of these were sent in 1903 to America to be grown for stock by Mr Sydenham. Those that came back from America were a mixture of all sorts but no more like my true Countess Spencer than night is like day.”
It has been suggested that the stock of Countess Spencer became mixed with another batch of sweet pea seed which Sydenham had sent to America for bulking, and that this was the reason that Countess Spencer gained a reputation for not being 'fixed'. It is also true that Countess Spencer was the first sweet pea variety to have an open rather than a clamped keel, and so would have been more at risk of cross pollination than the earlier sorts.