J. D. Hooker and Primary Data Sources (Primula pulchra)

P. denticulata, a common species near Lachen, Sikkim

The easiest way to investigate a species is to read secondary sources of information. These are often such works as monographs or regional floras. We are now at least one generation removed from some of the prominent explorers and plant hunters of the Himalaya, such as George Sherriff (1898-1967), Frank Ludlow (1885-1972), Frank Kingdon-Ward (1885-1958) and even further removed from such explorers as Joseph Dalton Hooker (1817-1911). When William Wright Smith and Harold Roy Fletcher wrote a series of articles (see bottom of this book list) in the 1940's on Primula, they effectively wrote a monograph of the Genus. This is a secondary source of information, but the great advantage of their work was that they could personally consult some of the explorers. Now that those explorers are no longer alive, we can't ask their opinion on the distinction between two species, or what the wild habitat was like or even the most obvious question : Where exactly did you discover that species?

Joseph Dalton Hooker (public domain)

Secondary sources can be frustratingly vague on that most basic of questions by copying the location given on the herbarium sheet or in the field notes. Often this location is given as the name of the nearest prominent place to the collection site - not where the specimen was actually collected. Such is the case of Primula pulchra (see my related blog post "Primula pulchra - Hide and Seek with P. gambleana". Hooker gave his unnumbered collection as the type of the species and cited the location as "Lachen, 12,000ft", June 8, 1849. Since Lachen is actually at an elevation of approximately 8,700ft, it is obvious that this is not the actual collection location. So exactly where did Hooker make this collection?

Hooker wrote a two part book called the Himalayan Journals about his travels in this area. Unfortunately this isn't a day-by-day account and so we have to piece together his route by reading several pages starting at pg 47 in Volume 2. We find that he was in the Zemu Valley, and camped at the junction of the Zemu and Thlonok rivers at a place we now call Tallem 27°46'50.48"N 88°29'31.50"E which is at an elevation of approximately 10,700ft - still not high enough to be the collection site. On page 50, Hooker tells us that he repeatedly ascended the north flank of Tukcham mountain (now called Lamo Angdang), but that he also went up the Zemu valley, either of which could get him to the correct elevation of 12,000ft.

Looking from Lachen to the head of the Zemu Valley (L side)
Photo: Abhinaba Basu (Flickr, CC)

Luckily we have access to a primary source of data - Hooker's diary and letters from that time. Thanks to Cam Sharp Jones at the Joseph Hooker Correspondence Project, Kew, I was able to read Hooker's diary entries for June 7th and 8th, but it was still unclear as to exactly where Hooker had ascended on June 8th. Luckily, Hooker wrote a letter to Archibald Campbell on June 9th describing in detail his activities on June 8th. Included is a hand drawn map showing his camp spot which is on the south side of the river, not the north side where modern expeditions camp. He describes his ascent of the mountain (Tukcham) to the south of his camp:

"I went up to nearly 14,000ft by a steep torrent, snowed the whole way up i.e. from 11,000ft up to perpetual snow at 13,500ft, which was there continuous and flanked by lofty black precipes wholly inaccessible. The fatigue of the ascent was very great from the snow, slipperiness, and enormous rocks which are constantly tumbling from above."

There is a gully rising up the mountain from Hooker's camp spot and there is no doubt in my mind that this is where Hooker went. There is an image of this gully
on a website detailing a trip up the Zemu. This a dangerous place to ascend and it is a testament to Hooker that he was able to do it without being injured, especially considering the rock fall. It is likely that Primula pulchra will be found in the nearby Kishong La or up the Zemu valley towards Green Lake, so I have hopes that someone will soon take images of this elusive species.

Pam Eveleigh © 2017

 

 

Read More

Primula pulchra - Hide and Seek with P. gambleana

In 1882, An article was published in the Journal of the Linnean Society titled "On some Undescribed and Imperfectly known Indian Species of Primula and Androsace" by George Watt. It was actually J.D. Hooker that wrote this article in Watt's name, using Watt's notes, though revising them where needed, and with the intention that this would be used in the Flora of British India that was being written at the time by Hooker.


Primula pulchra or not? (Smith collection)

The first new species of Primula described in the article is P. gambeliana (a spelling mistake of P. gambleana) from a collection (Watt 5483) made at "the Tra Cha Kumpa Kubra Rock (Black Kabur?) above Jongri (Dzongri), Sikkim 27°30'29.99"N 88° 9'9.45"E. It grows in moss and often in crevices of steep wet cliffs.

P. pulchra is the second new species described in the article, from a collection (s.n. 12,000 ft) made by Hooker at Lachen, Sikkim (27°43'2.18"N 88°33'29.02"E, probably in the Zemu valley according to Hooker's Himalayan Journals). Also noted is a syntype collection (Watt 5406) made at the upper Ratong Chu Basin, Jongri (27°32'38.68"N 88° 8'4.47"E) for which Watt 5268 is given as equivalent. This location is very close to the type location for P. gambleana.

Both of these species are figured: P. gambleana - Tab I, and P. pulchra Tab II. A (see image below). Hooker makes the comment under P. gambleana in the Flora of British India: "petiole not sheathed at the base as in P. pulchra, which this a good deal resembles".

Drawings from the Journal of the Linnean Society

If you compare the two drawings side by side, there are a lot of similarities between the two species. Both having a sheathing base, but the scales are much larger in P. pulchra. The most obvious difference is the leaf shape with the leaves of P. gambleana shown as orbicular though Smith & Fletcher later described them as "ovate-cordate or ovate-oblong rather than orbicular" and noted that the figure shows the leaves as more orbicular than is usual. The leaf base is described as usually deeply cordate but occasionally truncate. Smith & Fletcher describes the leaves of P. pulchra as oblong to ovate-oblong with a rounded or slightly cordate base. Both species are shown with an obvious scape with 1-10 flowers. The relative size of the plants on the types specimens are similar.

P. pulchra? capsule (L), P. gambleana capsule (R)
courtesy Royal Botanic Garden Edinburgh

Apparently, the most distinguishing feature is the seed capsule which was not known when the two species were described. P. gambleana has a cylindrical capsule, twice as long as the calyx and dehiscing by longitudinal valves. Seen in only one collection of P. pulchra (Tari, Sikkim, no collector) at Edinburgh is a subglobose capsule equalling the calyx dehiscing by a crumbling wall (Section Petiolares type). This collection is of 6 thin, sparsely flowered plants, and none show the sheathing base that is seen in similar plants in the type collections. Is this really P. pulchra in seed or is it another petiolarid species?

Primula sp Yak Desha = P. pulchra Smith?

In about 1985, George Smith made a collection from the area near Kanchenjunga that was identified as P. pulchra. It was awarded a PC in 1991 and may still be still in cultivation. This clone does not seem to produce the tall scapes of the type collection and it makes me wonder if it really is P. pulchra. In addition to this is a recent image from Yak Desha, Nepal which seem to equate to the Smith collection but again does not seem to be the same as the type collection of P. pulchra!

Perhaps the Smith collection is true P. pulchra, but it is important to get it right because it affects other related species P. chamaethauma and P. chamaedoron which have been lumped into P. pulchra by some authorities.

What is needed is lots of images, including the capsules, of both P. pulchra and P. gambelana from Sikkim in the Ratong basin (near HMI Base Camp) and the cliffs around Black Kabur, near Dzongri and also the Zemu valley. Only with this additional information can this puzzle be solved. If you can help, please contact Pam Eveleigh.

Pam Eveleigh © 2017

Read More