Friday, August 11, 2017

Tree of the Month: the Poison Nut Tree

Poison Nut Tree, Strychnos nux-vomica; artist unknown (BHL on Flickr).

It was Dr. William Roxburgh, botanist with the East India Company, who introduced me to the Poison Nut Tree. Actually, it was the beautiful illustration by his anonymous artist-assistant, now on Flickr. And to be honest, the chilling scientific name grabbed me first: Strychnos nux-vomica. That's strychnos as in strychnine (the poison’s name was derived from the plant’s), and nux-vomica for the deadly, nausea-inducing seeds (nuts, nux).

Roxburgh arrived in India in 1776, having been hired by the Company as a surgeon (physician). He also was a botanist, and it appears he did as much botanizing as doctoring. His dream job landed in his lap three years later, when the Company’s Madras botanist retired. Roxburgh gave up medicine, and moved to the coast of Coromandel, on the Bay of Bengal. It was a botanist’s paradise, with a diverse, fascinating, and—perhaps best of all—unknown flora.

The Company’s interest in the Coromandel coast was understandable. Areas rich in natural resources lay in close proximity, and the mouths of several rivers served as ports. Surprisingly, given how long Europeans had been in India, the flora was poorly known. It was hoped that species of value would be discovered—“such articles as may prove beneficial to the inhabitants as well as the natives of Great Britain, and which ultimately may tend to the extension of the national commerce and riches.”

Building on the work of his predecessor, Roxburg explored, collected plants of interest, and wrote descriptions that included features useful for identification.
“Leaves opposite, short petioled, round-oval, shining, smooth on both sides, entire, three-five-nerved, differing in size, from one and a half to four inches long, and from one to three broad. Stipules none. Flowers small, greenish white, collected on small terminal umbells …”
“Berry round, smooth, size of a pretty large apple, covered with a smooth somewhat hard shell, of a rich beautiful orange colour when ripe, filled with a soft jelly-like pulp. Seeds from two to five, immersed in the pulp of the berry.”

Roxburgh also noted native uses of plants.
“The wood of this tree is hard and durable, and is used for many purposes by the natives. It is exceedingly bitter, particularly that of the root, which is used to cure intermitting fevers, and the bites of venomous snakes (1) … The seeds are employed in the distillation of country spirits, to render them more intoxicating.”
This use of Strychnos seeds in alcoholic beverages is intriguing. True to its name, the Poison Nut Tree’s strychnine-laced seeds (nuts) are toxic. Even a single seed reveals its evil nature within minutes: racing heart, rapid breathing, convulsions, and muscular spasms with grotesque arching of the back and neck. (Contrary to the specific epithet, nux-vomica, nausea is rare.) Death almost always follows—through cardiac arrest, respiratory failure, multiple organ failure, or brain damage. The drama of death by strychnine has made it popular with murder-mystery writers, including Agatha Christie and Arthur Conan Doyle.
Strychnos seeds are rock-hard; unless crushed before consumption, they pass through intact (source).

Roxburg needed illustrations to go with his plant descriptions, so he hired native artists. In a sense, these artists were skilled botanical illustrators; plants, leaves, and flowers were common motifs in the exquisite patterns popular in Indian artwork. But left to their own devices, they produced illustrations in their own style—bold contrasting colors, plant parts appealingly arranged, and almost nothing to provide a sense of depth. Details important to botanists were often omitted when not critical to overall composition.
Floral decoration on tomb of Empress Noor Jahan, Taj Mahal (Wellcom Trust).
More realistic plant portraits were required, with shading and depth, and with all parts necessary for identification shown in detail. So the Indian artists were given training in proper botanical illustration. The result was what Richard Mabey (2015) called “cultural fusion … an exotic fusion of European precision and Mughal stylisation that revelled in the pure patterning of plants.” Critical botanical details were included, but in an appealing composition. This hybrid style is distinctive enough to have a name: Company Art.
Sappan, Caesalpinia sappan; artist unknown (BHL on Flickr).
Strychnos nux-vomica: Company Art (left) and a more traditional illustration, from Köhler’s Medizinal-Pflanzen, 1883 (source).

Roxburgh was a passionate botanist and hard worker. From 1791 through 1794, he shipped parcel after parcel of descriptions and illustrations to the Royal Botanic Gardens, Kew, in London—500 species in all. From these, the distinguished botanist and President of the Royal Society, Sir Joseph Banks (2), selected 300 for publication.

Plants of the Coast of Coromandel was published over a period of 25 years, 1795–1819. It was a grand three-volume set, with detailed descriptions and hand-painted copper engravings—a full-page illustration for each of the 300 plant species. In the Preface, botanist Patrick Russell praised Roxburg’s dedication: “Such commendable zeal in the service has not passed unnoticed by the Court of Directors [of the East India Company], which has lately honoured him with a handsome present of botanical books, as well as with other marks of approbation.”

Russell also recognized the contributions of pioneering botanist John Gerard Koenig, “to whom Indian Botany stands so highly indebted.” But nowhere were the botanical illustrators acknowledged, nor even named. The only reference was this: “[Roxburgh] had retained a painter constantly employed in drawing plants …”

The size and lavishness of Plants of the Coast of Coromandel guaranteed it would be accessible only to the privileged—wealthy enthusiasts, and individuals associated with botanical gardens and other institutions. But fortunately, times have changed. Dr. Roxburg has joined the open access movement! Now, anyone with internet access can indulge themselves in Coromandel plants and elegant Company Art.
Flame of the Forest, Butea superba; artist unknown (BHL on Flickr).

In 2007, Plants of the Coast of Coromandel from the Missouri Botanical Garden’s Rare Books Collection was digitized, and added to the Biodiversity Heritage Library (BHL). Six years later, the illustrations were uploaded to Flickr. It was on Flickr that I met Dr. Roxburgh and the Poison Nut Tree, through my role as a tagger.

In building online collections, machines and software do the lion’s share of the work, but there are tasks that only humans can do. A machine can scan a page of text, which is then interpreted by optical character recognition software. Plant names can be flagged in the process. But illustrations are incomprehensible, and so the plants remain hidden and undiscoverable until tags are added, by a human. Only then will they show up in searches.

Most days I spend a little time, usually less than 30 minutes, adding tags for names and geographic information to illustrations by Roxburgh's anonymous artists, slowly progressing through the plants of the Coromandel coast. Gorgeous engravings of exotic plants more than make up for any tedium. The challenge of updating 18th-century nomenclature also keeps me from getting bored.
I started tagging because of its worthiness. I use online collections regularly—specimens, literature, images—so I know the value of tags. But soon there were other reasons to continue. I enjoy reading accounts of botanical exploration in the 18th and 19th centuries, and I love the exotic plants and delightful artwork.
Rosy Milkweed Vine, Oxystelma esculentum; artist unknown (BHL on Flickr).

The Biodiversity Heritage Library needs more taggers!! No experience required—taggers range from fledgling citizen scientists to professionals. The Flickr collections include many kinds of organisms, not just plants, so you can work on your favorites. Want to learn more? Check out this example, a persuasive post about the value of tagging, and the BHL Tagging Tutorial.


(1) Strychnos nux-vomica is recognized in alternative medicine circles as a treatment for many conditions, but most claims aren't supported by experimental evidence. However, one study found that whole-seed extract of S. nux-vomica—in low doses—effectively neutralizes venom from the viper Daboia russelii (in mice; Chatterjee et al. 2004).

(2) The first version of this post mistakenly assigned responsibility to Joseph Hooker.


Mabey, R. 2015. The Cabaret of Plants. WW Norton & Co.

Roxburgh, W. 1795-1819. Plants of the coast of Coromandel: selected from drawings and descriptions presented to the hon. court of directors of the East India Company. Accessed 7 Aug 2017.

Wikipedia. Strychnos nux-vomica, and Strychnine.; Accessed 7 Aug 2017.

This is my contribution to the August gathering of tree-followers kindly hosted by The Squirrelbasket.


  1. Well, how fascinating was all that!
    I recall the words "nux vomica" from something I read as a child - probably Arthur Mee's Children's Encyclopedia, but I hadn't heard it for years.
    Isn't the word "Coromandel" romantic?
    Isn't it just typical those native artists did all the work for no credit!
    I will definitely have a look at those Flickr images - your tagging work is so worthwhile.
    I often wonder how we found out plants were poisonous. There must have been a lot of mistakes on the way. And isn't it amazing that even a poison can cure certain snake bites.
    Thank you so much for another great contribution to our knowledge of trees!
    All the best :)

    1. Thank you, Pat! I agree -- Coromandel sounds so romantic, the promise of exotic adventure :-) Thanks considering the Flickr images, if you have any questions please ask. Of course the challenge is finding time. Too many neat things to do in this world! (that's NOT a complaint)

  2. Your research, as always, is impeccable and far-ranging - and great to read. I always liked how in the 'olden days' that a lot of doctors would also be botanists. I guess in those days knowing a plant and what it looked like was important so you're treating the patient with the correct medicine (although I have read books with examples of doctors who had no idea and just bought whatever the herbalist was selling - reminds me today of doctors and drug companies, but I won't get into that!).
    I was really interested to read about the tagging project too.

    1. Tim, thanks for reading. My posts have gotten less frequent and longer, and are now basically "articles" or "stories". That's the kind of writing I like, and blogging is great practice, a place to try things out. I know my writing has improved because of blogging. Btw, I had several pieces accepted this year :-)

    2. That's very exciting. Are any of those pieces available online? You're writing is very good, I wouldn't be surprised if one day I'm on Amazon buying a book authored by you.

    3. Thanks, Tim!! The article just published was in our paper, which has a paywall. But I will post it, along with a few more photos. The second will be online and free--Yellowstone (National Park) Science. It will be up in October, and I'm sure I'll post about it ;-)

      A book?! seems beyond my abilities at this point ... but who knows
      best wishes

    4. I will look forward to you posting those articles. Best wishes :)