Primula sinensis....or Not

Primula sinensis is a familiar houseplant, though perhaps not as popular as it has once was. Like Primula obconica, this species is known for its beautiful variations in flower colour and form . Because of this variability and its availability at the time, it was the subject of some of the first studies done on genetics and heredity. Using the principles of Gregor Mendel ,  R.P. Gregory conducted experiments with Primula sinensis from 1903 until his death in 1918, investigating 18 pairs of characteristics as described in a posthumous paper by co-collaborator William Bateson (see also Mendel's Principles of Heredity, A practical Example starting pg 293, with color illustrations). With all its variations, it is no wonder it was a popular garden plant, still desired, but unfortunately it can cause allergic contact dermatitis which may have contributed to its scarcity today.

Primula praenitens from Bot. Reg. 7:t 539. 1821.

The origins of Primula sinensis in the wild are unknown as the original material came from gardens at Canton (Guangzhou), China. It was described with illustrations twice in 1821, as Primula sinensis Sabine ex Lindley in Coll. Bot. (Lindley) t. 7. 1821 and as Primula praenitens Ker Gawler in Bot. Reg. 7: t. 539. 1821. The description by Ker Gawler points out the previous use of the name Primula sinensis by Loureiro in 1790 which is given as the reason for using a different name than that given by Sabine. Though this is indeed the case, it was thought that Loureiro's name was invalid and so the name Primula sinensis has been used since. However, it is now determined that Loureiro's description is valid and so Primula sinensis Sabine ex Lindley is now "nom. illeg." The name Primulidium sinense (Sabine ex Lindley) Spach was also published in Hist. Nat. Veg. (Spach) 9:355. 1840 but this is deemed nom. illeg. as being superfluous for Primula praenitens.

So the correct name for this species is Primula praenitens!

According to John Richards, the name "Primula sinensis" is "conserved", but I can find nothing official in the International Code of Nomenclature list of Conserved & Rejected Names though the most recent version is not yet available online. Richards also notes that Primuls sinensis may be only the cultivated form of the wild species, Primula rupestris which was described in 1918 by Balf.f. & Farrer.
Halda considers Primula rupestris to be a synonym of Primula sinensis and discusses this in his book "The Genus Primuls in Cultivation and the Wild", pg 63.
The Flora of China published the name Primuls sinensis but the online version notes that the correct name should be P. praenitens. It lists Primula sinensis as being from Guizhou and Sichuan and Primula rupestris from W Hubei and S Shaanxi and the two are distinguished in the key by Primula sinensis having a larger calyx in fruit and not retaining old leaves around the base of the plant (and by location).

Historical images taken by Ernest Henry Wilson are here and here. A beautiful image from the wild can be seen here.

So what is the species described by Loureiro as Primula sinensis? I guess that will be the subject of another post!