Finding Primula stirtoniana (updated)

As for any species, understanding comes with information and particularly so for the rare Primula stirtoniana. In 2006, I grew a plant identified as P. stirtoniana and at the time I was happy enough with that identification as it matched roughly the drawing in John Richards’ book and the description of leaves “only some of which tend to be lobed”.  However, since that time I have read the description by Smith and Fletcher which describes the plant as having the leaves “particularly the upper two-thirds, strongly incised-dentate”. Since I am a visual person, it wasn’t until I saw a painting by Lawrence Greenwood that I was able to get a good idea of what this species looked like (and realise that wasn’t what I was growing). The type material is sparse, but now that it is available online, the description of the species is much easier to match especially when you look at the dissected plant on the isotype E00024518 at Royal Botanic Garden Edinburgh.

Courtesy: Royal Botanic Garden Edinburgh

Type Location
According to the protologue in J.Linn. Soc., Bot. 20: 15. 1882 and repeated in Hook.f. Fl.Brit. Ind. iii. 495 , the type is “G. Watt, Kanglanamo Pass, alt. 14,000-16,000 ft.” in the Sikkim Himalaya. According to Smith and Fletcher, this species was discovered by George Watt (#5419) in 1881 on the Surkia La, near the Kanglanama La, on the NW Sikkim-Nepal border. I have been unable to find the exact location of the Surkia La, but according to Douglas Freshfield in his book “Round Kangchenjunga” he says “it is doubtful if the Kangla Nangmo is a pass at all. It appears rather to be the name given to the plateau N of the Kang La, which sends down glaciers on both sides of the ridge”. So that means that our type location is somewhere near 27°31'21.26"N 88° 3'35.88"E. From Smith and Fletcher, Primula stirtoniana was also collected on the Pey-kiong-la near Jongri (Dzongri) (exact location unknown) and the Nyegu La (exact location unknown) near the Nepal frontier and then at Dungshinggang (Mountain), Bhutan by Ludlow & Sherriff. Unfortunately, other than a low resolution, black and white image in Fletcher’s “A Quest of Flowers” pg 52, taken by Sherriff at Dungshinggang, I have no images of P. stirtoniana from these locations.

A Species From Arunachal Pradesh

In 2011, images came back from Arunachal Pradesh between Lugathang and the Zelung La of plants which looked like Primula waddelili though the corollas did not have the characteristic deeply bifid lobes. Looking at Ludlow and Sherriff’s field notes revealed a collection #751, from Mago on August 2, 1934 which had been identified as P. stirtoniana. On August 1, 1934 Ludlow and Sherriff had parted ways for a few days with Ludlow making his way from Mago toward Lugathang which is about 11kms away in a direct line but there is no indication in the field notes which person made this collection. This collection isn’t online but a friend was able to go to the British Museum and photograph it. The collection is only one small plant but is seems to match the 2011 images.

Careful tracking of the Ludlow & Sherriff 1934 route and comparing with the field notes reveals that collection #751 was made by Sherriff near to the Debong La, just to the west of Dyuri and about 9 miles in a straight line from from the Zelung La.

So is this species from Arunachal Pradesh a match for P. stirtoniana?
Firstly we can look at the protologue for Primula waddellii in Notes of the Royal Botanic Garden Edinburgh 9: 56. 1915 in which Balfour speculates that P. waddellii may be a microform of P. stirtoniana but that there are differences, mainly in the leaves. I have images of Primula waddellii from Bhutan and Tibet, so below are a series of images comparing P. waddellii to our mystery plant which I will call “aff stirtoniana”.

Calyx: aff stironiana has ovate-lanceolate lobes with an acute apex whereas waddellii has lanceolate lobes with a blunt apex. Both are scabrid.

Flower: purple color, white eye, hairs in the throat compare favorably; shape varies in aff stirtoniana but never reaches the extreme of P. waddellii.

Leaf: Both are spoon shaped with teeth in the apex or upper half and are scabrid. The number of teeth vary from 3-7 in aff stirtoniana and 6-14 in waddellii.

 

Toshio Yoshida Images

Toshio has three images labelled P. stirtoniana from Nepal on his website. Though the resolution isn’t enough to see fine detail, in Y00673, in Y00672, we see leaves with finely incised apex. In image Y00674 we see a species with oblanceolate leaves and obvious runners. Though P. flagellaris is not listed for Nepal, this image matches that species and we shouldn’t be surprised that flagellaris is here as the type location is in the Zemu Valley, Sikkim, only 40 Kms to the NE of Kanglanamo – so if P. stirtoniana can be in Nepal, so can P. flagellaris. Hara lists specimens of P. stirtoniana from West, Central and Eastern Nepal in “AnEnumeration of the Flowering Plants of Nepal, V3”.

 

Conclusion

As I said to start, the more information we have, the better will be our conclusions. Our mystery plant from Arunchal Pradesh seems to approach more closely P. stirtoniana but there is a lot of variation in the plants – more so than can be illustrated here. A return visited to the type location at Kanglanamo, and a good set of detailed images would certainly help the situation. Also being able to review the existing herbarium material (which is not online) and to see detailed images from Nepal and Bhutan of P. stirtoniana and P. waddelli would be beneficial.

 

But what was the plant you originally grew? And how does this relate to the similar species P. muscoides? I guess that will be another post!