The Truth about the Blue Nivalids (P. youngeriana)

Of the Blue Nivalids, this perhaps one of the easiest species to write about. That is because it is little known, probably only collected once ever, by Sherriff and Taylor (PDF) , on the Mira La, Tibet in 1938. A search of the Chinese Virtual Herbarium turns up no Chinese collections and that could be because to get to the Mira La is a two day hike and suitable elevation isn't accessible via road in that area. Above is the holotype from the British Museum (specimen BM00099651).

Mira La, Tibet (Namcha Barwa Peak in the right background)

The Mira la is a pass of 15,800 ft (slightly higher on Google Earth), NW of Tsela Dzong (on the Tsangpo river) and SW of Bayi (Nyingchi on Google Earth). The area is drier than surrounding valleys and mountains, is less forested, and screes predominate, though many high alpine lakes dot the landscape including a small one at the foot of the pass on the south side.

Primula littledalei (under boulder to right) habitat similar to P. youngeriana

Primula littledalei, Mi La, Tibet

In the original description, the species is compared with Primula obtusifolia, another nivalid but from the NW Himalaya. The habitat where P. youngeriana was found - growing under huge boulders in dry moss, is strongly similar to that of P. obtusifolia but also to P. littledalei which was growing in abundance on the Mira La too. Sherriff mistakenly thought P. littledalei was P. rotundifolia which has similar orbicular leaves. P. obtusifolia has oblong leaves like P. youngeriana.

Sherriff thought that P. youngeriana was an unusual form of Primula macrophylla var. macrocarpa (now P. megalocarpa) but with flaccid leaves and copious white farina, not something new. What makes P. youngeriana so distinctive is that the bracts are long, linear and acute at the tip and the calyx is large (1-1.5cm) and cut to the base into lanceolate, patent (spreading) lobes which are acute and densely farinose inside. P. megalocarpa also has calyces which are cut to the base but that species differs in other characteristics.

A portion of E00024585
courtesy of the Royal Botanic Garden Edinburgh

The flowers of P. youngeriana are deep blue-violet, sometimes lilac, with a white eye and the corolla lobes are entire. See P. littledalei, P. rotundifolia, P. obtusifolia and P. megalocarpa in the Species Gallery. 
 

This post is one in a series about Chinese blue nivalids. See the introduction post.

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A Trip to Utah, USA

 

For two weeks in October, 2015 I was able to take a short holiday in Utah, USA. Being very late in the season, I wasn’t able to see any Primula in flower but I did see plants in seed. According to the Flora of North America, Primula species that grow in Utah include Primula parryi, Primula cusickiana var. maguirei, Primula cusickiana var domensis, Primula specuicola and Primula incana.

 Wet Seepages in Zion

 

Dodecatheon pulchellum var. zionense

 

While in Zion National Park, we hiked to several places where there were wet, cool seepages that provided a unique habitat for plants unable to withstand the hot dry environment that dominates the Utah summer. One plant that caught my eye was a Primula-like species that had large green leaves and unmistakable Primula seed capsules. Not having a wildflower identification book with me, it wasn’t until I was able to consult information at the visitor’s center that I found out this was Dodecatheon pulchellum var. zionense. Without the telltale flowers to indicate a Dodecatheon, I was very struck with how very Primula like this species was and perhaps now I am more convinced of the results of genetic testing that indicates that the Genus Dodecatheon should be part of the Genus Primula. If so, the new name is Primula pauciflora var. zionensis.

Primula specuicola

Several days later, I had a short time in the Moab area and was able to visit a known location for Primula specuicola. This is a truly lovely species that is copiously covered in white farina that contrasts nicely with the purple-pink umbels of relatively large flowers. This species grows in exactly the same type of wet seepages that I had seen in Zion supporting Dodecatheon pulchellum. Again the similarity of environmental preferences between the Dodecatheons and Primulas in this area was evident.

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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!

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