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Millennium Seed Bank blog

Welcome to the Millennium Seed Bank blog. There is a lot going on behind the scenes at Kew's Millennium Seed Bank (MSB) - not only here at Wakehurst but also with our partners all over the globe. We will be blogging about our seed collecting trips, local events, research projects and discoveries as well as everyday goings on.

We currently have seeds from more than 30,000 species of wild plants in long term storage and continue to receive seed collections from all over the world. It is an amazing place to work and we hope to share our passion for seed conservation with you via our blogs. 

Find out more about Kew's MSB | Adopt a seed for £25 or save a species outright

Ever had an ice cream bean for dessert?

By: Wolfgang Stuppy - 31 Aug 2012
This month the Millennium Seed Bank's Seed Morphologist, Wolfgang Stuppy, has us salivating over the remarkable fruits of the ice cream bean (Inga edulis).
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Ever since I can remember I have been fascinated by plants, especially all things edible that come from them. And the more exotic the plant, the better! After blogging about the cashew nuts, a very well-known exotic treat, I decided to now choose a seedy delicacy that is less well-known, at least in our temperate climate.  

Sweet seeds

The legume family (Leguminosae or Fabaceae) is an amazingly diverse (nearly 20,000 species worldwide!) and incredibly useful group of plants. They feed us with beans, peas, lentils, soya and loads of other pulses and they treat us with delicious peanuts, tamarinds and liquorice. When travelling to far-away tropical countries, we are likely to encounter lesser spotted members of this miraculous family and some of them bear strange-looking but excitingly delicious fruits. One of these scrumptious exotics is the South American ice cream bean, Inga edulis, locally called ‘guaba’ (pronounced ‘wuba’). Behind this mouth-watering name lies a beautiful tree with a remarkable fruit.

Fruit of Inga edulis
 Fruit of the ice cream bean tree (Inga edulis, Leguminosae) photographed in its native Brazil 

A two metre long candy bar!

Reaching a height of up to 30m (96ft), an ice cream bean tree produces cylindrical and often spirally twisted bean-like pods that grow up to more than two metres(!) in length. This is no hoax! One of my colleagues at Kew, Dr. Terry Pennington, is a specialist on the genus Inga. Whilst discussing this blog with him, he told me that he was supervising Inga trials in Amazonian Peru in the early 90’s, they had a competition on the local radio to find the longest ice cream bean. The winner brought one which measured 2.07 m long.

Inside, lined up in one row, the pods contain numerous large purple-black seeds embedded in an edible, translucent-white pulp. The sweet flavour of the spongy pulp resembles that of vanilla ice cream, hence the name. Basically a yard-long candy bar that grows on a tree, most people will be sufficiently impressed by the size of this fruit and its delicious flavour. As a practicing ‘seed nerd’, however, I find something else quite extraordinary, too. 

Inside an ice cream bean

Inside an ice cream bean lie the juicy delicious seeds


Seeds of Inga edulis

Seeds of Inga edulis with and without their white fleshy seed coat. What is left after the white juicy part has been eaten is the bare naked embryo

Unlike most fleshy fruits, the sweet pulp of the ice cream bean is not produced by the fruit wall but by the seed itself. Usually, seeds are covered by a hard seed coat to protect the precious embryo inside against both the elements and hoards of seed-eating critters. In the ice cream bean, however, the entire seed coat becomes soft and fleshy. Once you have nibbled a hole in it at one end, you can basically strip it off like a sock and suck the sugary treat! What remains is the purple-black embryo. Although it looks very dark on the outside, underneath its black skin, the embryo is actually green.

Embryo cross section of ice cream bean seed

Cross section of the embryo of an ice cream bean (Inga feuillei, see below) showing that underneath its dark purple skin the embryo is actually green.

The genus Inga contains about 300 species of shrubs and trees, all native to the warm and tropical parts of the Americas (including the Antilles) and most of them occurring in the Amazon rainforest. Although Inga edulis (edulis meaning ‘edible’) is the most common species that is referred to as ‘ice cream bean’, there are a number of other Inga species that spoil us with equally delicious fruits, for example Inga feuillei (called ‘pacay’ in Peru), I. rhynchocalyx, and I. spectabilis. Their fruits differ in shape and size but inside they are very similar.

Because of their delicious taste, ice cream beans are very popular in many parts of Central and South America, where they are almost always eaten raw. During the tropical wet season when fruits are abundant, monkeys and birds feast on the sweet pulp and scatter the soft embryos.

But aside from their edible fruits, Inga trees are also useful in other respects. Like many members of the legume family, Inga trees have the ability to fix nitrogen with the help of Rhizobium bacteria which they house in specialized root nodules. Because they introduce nitrogen from the air into the soil, these root nodules act like fertilizer and help to improve soil fertility. Moreover, Inga trees have long been grown by indigenous Amazonians for food, shade and timber and they have also proven very useful as shade trees in cacao, coffee, tea, black pepper and vanilla plantations.


Fruit of Inga rhynchocalyx

Another delicious ice cream bean: Inga rhynchocalyx, a native of the Amazon rainforest

But it’s not only the fruits that make Inga trees so very special. Their flowers, which produce the delicious ice cream beans, are pretty amazing too. They only open for one night and wither very quickly in the early morning. Like many other nocturnal flowers, they are large, white in colour and arranged in dense clusters (inflorescences). The individual flowers consist mainly of a brush-like tuft of stamens with long filaments. Flowers of this type are typically pollinated by bats. Their furry faces get powdered with pollen as they search for nectar at the base of the flower. Recent research into Inga has shown that at least in some species (e.g. Inga sessilis), hummingbirds are the first visitors just after the flowers open, followed by bats as well as hawkmoths throughout the night.


Inga rhynchocalyx flowers

The nocturnal, brush-like flowers of Inga rhynchocalyx only last for one night and are mainly pollinated by bats 

One last thing...

In my blog post on the cashew nut I was raving about eating embryos and how delicious they are. Those of you who read this blog might wonder as to why the birds and monkeys that feast on ice cream beans don’t also eat the embryos wrapped inside the juicy seed coat. Good question indeed since hungry animals usually devour everything they find palatable and digestible. The answer to this is not only a fascinating example of the co-evolution between plants and animals but also a lively illustration of how plants pursue different strategies to achieve the same goal: in seeds it’s all about the safe dispersal of their embryos.

Ice cream bean embryo

Why would animals only eat the fleshy seed coat and not the large soft embryo (here cut in half) inside?

When it comes to protecting their seeds, animal-dispersed fruits that offer edible rewards to attract animal dispersers have two options to increase the chances of their seeds to escape destructive mastication: mechanical or chemical protection. Plainly this means that either seeds are encased in a really hard shell (see my blog on the Texas mountain laurel) or they are laced with bitter-tasting substances (usually tannins) and/or poisonous chemicals that teach uninitiated animals enjoying a particular fruit for the first time a lesson they won’t soon forget. If you need experimental evidence for this, try chewing the seeds of grapes, apples, oranges, avocados or papayas. In the unlikely event that you actually enjoy the experience, please do note that the seeds of apples and other members of the rose family (e.g. plums, apricots and bitter almonds) contain highly toxic cyanide (actually a cyanogenic glycoside called amygdalin, to be precise). But fear not! You are unlikely to have sufficient apple seeds at your disposal to actually poison yourself. For example, one kg of Fuji apple seeds contain the equivalent of c. 700-800 mg hydrocyanic acid (see this article from Food Chemistry for more information). When ingested, the lethal dose is about 50 mg of cyanide (depending on your body weight) so you would have to eat about 60-70 g of fresh apple seeds. That doesn’t sound like a lot but how many seeds is that? Since I couldn’t find any reliable figures for the weight of an average apple seed, I chopped up my Braeburn that I bring for lunch every day. I found three seeds in it that weighed 211 mg altogether, so that’s 70 mg per seed. To get to the potentially ‘lethal dose’ of 70 grams of seeds I would need 1,000 apple seeds. My cherished lunchtime Braeburn yielded only three fully developed seeds so I would need over 300 more Braeburns before I could contemplate to seriously poison myself. Hmh...

Returning to the actual matter of this blog, in the case of the ice cream bean this means that in the absence of even the slightest mechanical protection, the embryo is almost without doubt (I haven’t tried it!) very bad-tasting, usually bitter, if not actually poisonous.


- Wolfgang -

 All photographs by Wolfgang Stuppy



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Love nuts? Love seeds! But which one is the tastiest of all?

By: Wolfgang Stuppy - 24 Jul 2012
After previously exploring colourful, enigmatic, poisonous and sadistic seeds, in his new blog, Wolfgang goes nuts about nuts.
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I absolutely love nuts! They are healthy, taste great and being a Seed Morphologist, I obviously have a very special relationship with them. The latter is fuelled by the strange awareness that every time I eat a nut, I eat an embryo. Yuk? Well, read on!

To me, the most delicious nut of all is the cashew. No other nut can match its fine flavour and soft creamy texture. If you are also nuts about nuts, you will undoubtedly know cashews, even if you (incomprehensibly) prefer macadamias, Brazil nuts or pecan nuts. I wonder, though, how many people know the plant that cashew nuts come from and how unusual and amazing the actual fruit they are borne in looks like. Hence this blog...

Cashew fruits

The vibrantly colourful fruits of the cashew tree, Anacardium occidentale

Cashew apples and cashew nuts

Cashew nuts grow on trees with large, beautiful bright green leaves. Nowadays cultivated and naturalised almost all over the tropics, the cashew tree (Anacardium occidentale, Anacardiaceae) is originally native to the coastal plains of north-eastern Brazil, where it forms part of the so-called restinga* vegetation. Long before European colonisation in the sixteenth century, Brazilian Indians have relished the delicious fruits. Called ‘acajú’ by the members of the Tupi tribe, the name was converted by the Portuguese into ‘cajú’ and eventually became ‘cashew’ in English.

Cashew Tree

A cultivated cashew tree (Anacardium occidentale) in Brazil


Cashew flowers

Young cashew fruits with their stalks starting to swell, top right: flowers 

From very humble, tiny, first white, then pink flowers arise rather large, brightly coloured (there are orange-red and yellow varieties) and somewhat weird-looking fruits. When ripe they resemble a very soft pear with a hard, kidney-shaped nut tucked in at one end. The pear-like part, also called ‘cashew apple’ (whoever came up with that name has never seen an apple next to a pear!) is extremely juicy and sensitive to pressure which is why you can’t find them in our supermarkets. In Brazil I have seen them offered in roadside stalls where they were carefully displayed in egg trays.

Cashew fruits on the tree

Ripe cashew fruits on the tree  

Cashes fruits in egg tray

'Cashew apples' are so soft, they need to be treated like raw eggs (here in a roadside stall in Lindóia, Brazil) 


Hard sell methods aside, what’s most unusual about the cashew fruit is that the fleshy bit is not formed by the swollen ovary of the flower as in ‘normal’ fleshy fruits. Rather, the cashew apple is formed by the hugely swollen stalk of the flower which is why you wouldn’t find any seeds in it. If you want to find the seed you must open the fertile part that is formed by the ovary of the flower, namely the hard, kidney-shaped ‘appendix’, better known as the ‘cashew nut’.


Image 007_Cashew apple section

A longitudinal section of a 'cashew apple' proves its origin from the flower stalk; there are no seeds, just flesh 


Ever had to stuff your mouth with a cotton ball soaked in milk?

Sounds delicious but here’s a word of warning to those who love to travel in the tropics. If you ever encounter a fruit-laden cashew tree, restrain your enthusiasm, at least for the ‘nutty’ bit. Whilst the amazingly succulent cashew pear, err... apple, is harmless and best enjoyed by sucking out the sweet juice and discarding the stringy-fibrous residue, the shell of the cashew nut is poisonous owing to an acrid phenolic oil, called urushiol. Urushiol causes dermatitis which is why the cashew nut was once also called ‘blister nut’. The same nasty oily chemical is found in other members of the Anacardiaceae. Among these close relatives of the cashew tree are notorious plants such as the poison ivy (Toxicodendron radicans), poison sumac (Toxicodendron vernix) and poison oak (Toxicodendron pubescens & T. diversilobum) but also mango (Mangifera indica; urushiol is found in the sap and fruit peel!).

If you try to crack a fresh cashew nut with your teeth, you will soon be blessed with a painful blistering rash in and around your gob (if it’s any comfort, the pain can be soothed by stuffing your mouth with a cotton ball soaked in milk). That’s also the reason why you will never find unshelled cashew nuts on supermarket shelves whereas other nuts like walnuts, hazelnuts, almonds and pistachios are quite often sold ‘whole’. 

Image 008_roasting cashew nuts

How to prepare 'home-grown' cashew nuts: roasting the nuts in a fire destroys the poison and the charred shells can easily be removed


Why cashew nuts are expensive

Because of the problems caused by the toxic shell of the nut, Latin Americans, West Indians and West Africans have long used only the succulent ‘cashew apple’ making it into wine and refreshing beverages, similar to lemonade, such as the Brazilian ‘cajuado’. However, on a worldwide scale the seed of the cashew tree is still the main commercial product, despite the laborious cleaning process that makes cashew nuts one of the most expensive of all nuts (at least in the UK macadamias cost a lot more than cashews). The safest way to enjoy ‘home-grown’ cashew nuts is to roast them in a fire and then remove the charred shell as shown in the pictures above.

In the wild, the brightly coloured, 5-10 cm long cashew apple acts as a tasty reward for the animals it needs for seed dispersal. Fruit bats, monkeys and bats pick the fruits to feed on the yellow- to scarlet-coloured apple but discard the poisonous nut, leaving the seed inside unharmed. 

Image 009_bag of cashew nuts

Cashew nuts off the supermarket shelf as we all know and love them


About eating embryos

Every nut contains a seed and as such, logically, also an embryo (i.e. a little baby plant that ‘hatches’ from the seed upon germination). Therefore, every time you eat a nut, you eat an embryo. But this is not like eating a microscopically small embryo when you eat a chicken egg. The edible part of the nuts we eat as nibbles consists of nothing else but the embryo. Here’s an experiment for you that proves my point: next time you eat a cashew try pulling it apart and you will see that it splits into two halves, the cotyledons of the embryo. There is even a tiny shoot axis with miniscule leaves in between them! 

Cashew nut in half

A whole cashew nut, botanically an embryo, and one split in half, revealing its true nature: a baby plant with two leaves (cotyledons) and a shoot axis



Oh, one more thing....

We botanists use the term ‘nut’ in a very different and much more rigorous sense than ‘ordinary people’ do in their everyday language. For the food industry, chefs and 'regular' consumers who enjoy a tasty nibble, any large edible kernel that requires forceful liberation from a hard shell before consumption is unscrupulously addressed as a ‘nut’. In a botanical sense, a ‘nut’ is only a nut if it consists of nothing but the mature ovary of an indehiscent (= non-opening) fruit with a hard, dry shell, usually harbouring a single seed. This is true for hazelnuts (Corylus avellana, Betulaceae), walnuts (Juglans regia, Juglandaceae), pecan nuts (Carya illinoiensis, Juglandaceae), acorns (Quercus spp., Fagaceae), and unshelled peanuts (Arachis hypogaea, Leguminosae), though the latter often (and annoyingly to botanists!) contain more than one seed. Other culinary ‘nuts’ are, in fact, the stones of drupes (= stone fruits), such as unshelled almonds (Prunus dulcis var. dulcis, Rosaceae), pistachios (Pistacia vera, Anacardiaceae), and, in all honesty, also cashew nuts (Anacardium occidentale, Anacardiaceae). I didn’t want to make things too complicated but, working for Kew, I finally have to break the truth about the cashew nut. Although hardly recognizable as such, the shell of a cashew nut does indeed display the three defining layers of a drupe: an outer skin, a very thin, quick-drying but nevertheless soft middle layer, followed by the dominating hard, woody stone.

As a final blow to the culinary nut-concept, it has to be unveiled that unshelled Brazil nuts (Bertholletia excelsa, Lecythidaceae), macadamias (Macadamia integrifolia and M. tetraphylla, Proteaceae), ginkgo nuts (Ginkgo biloba, Ginkgoaceae) and pine nuts (Pinus pinea, Pinaceae) are purely seeds in a botanical sense because their shell consists of the seed coat.

- Wolfgang -

All photos by Wolfgang Stuppy

*Restinga: a distinct type of tropical and subtropical forest found on acidic, nutrient-poor soils at the the Atlantic coast of Brazil.


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Pretty little liars

By: Wolfgang Stuppy - 18 Jun 2012
In his fourth 'Seed of the Month' series, Wolfgang Stuppy exposes some fraudsters of the plant kingdom including the pretty but poisonous seeds of Abrus precatorius.
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In my last blog I debunked some sadists of the plant world and now it is time, as promised, to expose the fraudsters of the plant kingdom. Hang on a moment, you may think! How could plants commit fraud when they can’t think? Well, it seems that evolution has done the ‘thinking’ for them.

Take the pretty but dangerous crab’s eye or rosary pea (Abrus precatorius), a member of the legume family (Leguminosae/Fabaceae) that is found throughout the tropics. When its fruits open, they reveal some very attractive looking shiny bright red-and-black seeds. The gaudy display catches the attention of birds. After all birds have very similar colour vision to humans (even better, in fact - they can see part of the UV spectrum!). In ‘dispersal sign language’, the colour ‘red’ is generally understood to advertise something juicy and edible, such as a sweet berry or stone fruit (think cherry!), for example.

Dispersing seeds of Abrus precatorius

Dispersing seeds of Abrus precatorius (Image: Gwilym Lewis)  

The lollipop effect

By the way, this colour scheme already works with very small children. As many parents can testify, children clearly understand the message sent out by a red lollipop from an early age, and – worryingly dangerous - also from any red fruit they encounter in the garden. So to birds, the shiny round seeds of the crab’s eye represent the equivalent of sweet lollipops. But in reality these seeds are very hard and dry and have nothing edible to offer. Birds hungry or curious enough to pick up one of the seeds may carry it for a short distance but discard it as soon as they discover the scam. Those birds that are not so clever might even swallow the seeds and as long as they haven’t got a strong gizzard, like the specialised seed eaters, the seeds pass through the bird’s gut without harming it.

 Abrus precatorius seeds

 Bright red seeds of Abrus precatorius (Image: Wolfgang Stuppy) 

Pretty but dangerous

Whilst the seeds of the crab’s eye are useless to birds, they are treasures to makers of botanical jewellery. In many tropical countries, seeds are strung together into beautiful necklaces, earrings and bracelets.

Abrus precatorius necklaceAbrus precatorius bracelet

Botanical jewellery made from the seeds of Abrus precatorius (Image: Wolfgang Stuppy)

However, handling some seeds is a very dangerous business and those of the crab’s eye are the most dangerous of all. Despite their great beauty, the seeds of Abrus precatorius contain abrin, one of the strongest plant poisons known. With an estimated lethal dose for humans of between 0.1 and 1 microgram per kilogram of body weight (experiments to determine the precise dosage are difficult to conduct!), less than 0.003 grams could kill a child. Fortunately, the seeds have a very hard seed coat and as long as they are not damaged, they are harmless, even if swallowed (don’t try this at home!). However, the manufacture of botanical jewellery can become a hazardous occupation if holes have to be drilled to thread seeds together. The dust from crab’s eye seeds can cause blindness on contact with the eyes, and inhalation or contact with open wounds has even worse consequences. 

What a way to go!

Symptoms of poisoning appear only hours or perhaps days after contamination; they include nausea, vomiting, severe abdominal pain, diarrhoea and a burning sensation in the throat. Later, drowsiness and ulcer-like lesions in the mouth and oesophagus, convulsions and shock finally lead to coma and death. Not a nice way to go! For adventurous types of the kind that indulge in fugu (Japanese for puffer fish), there is a simple way to detoxify the perilous seeds. At temperatures above 65°C, abrin breaks down so that the seeds are even allegedly edible after boiling (and don't try this at home either!). 

The crab’s eye is not the only cheater

Apart from the crab’s eye, there are other examples of fraudulent seeds, most of which are also members of the legume family. Because of their hardness and shiny colours, all of them star prominently in botanical jewellery. Among the favourites are the pure red seeds of coral trees (members of the genus Erythrina) and others such as the red bead tree (Adenanthera pavonina) from south-east Asia and Australia, and the Texas mescal bean (Dermatophyllum secundiflorum), a native of the south-western United States and Mexico (see my previous blog on the Texas mountain laurel). 

Flowers of Erythrina caffraErythrina herbacea seed pod

Image left: Flowers of Erythrina caffra; image right: Seeds of Erythrina herbacea (Images: Wolfgang Stuppy)

Even more eagerly sought are bicoloured red-and-black seeds like those of Abrus precatorius and others. Apart from the crab’s eye, such seeds can occur in certain species of Ormosia and Rhynchosia from Central and South America as well as in coral trees (Erythrina spp.), such as the Malagasy Erythrina madagascariensis

Necklace made from Ormosia seedsNecklace made from seeds of Ormosia spp

Botanical jewellery made from Ormosia spp. (Images: Wolfgang Stuppy) 

Ormosia coccinea seeds

Seeds of Ormosia coccinea (photo by Wolfgang Stuppy) 

One last thing... some people like to toy with their necklaces by putting them into their mouth. If you happen to be an aficionado of botanical jewellery, this might not be a good idea!     

- Wolfgang-

All above images by Wolfgang Stuppy are copyright Board of Trustees, Royal Botanic Gardens, Kew



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The sadistic dispersal strategy of the puncture vine

By: Wolfgang Stuppy - 08 May 2012
In his third 'Seed of the Month' blog series, Wolfgang Stuppy warns us of the 'dangerous' seeds of Tribulus terrestris.
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Traveling with animals is surely the most successful dispersal strategy that plants have evolved. Some want their fruits and seeds to be swallowed so that they travel as stowaways in the gut of an animal, whereas others prefer to latch onto the outside of passers-by.

Tribulus terrestris flower

The puncture vine: flower with fruit below

Sticky hitchhikers

After a walk through the countryside we often find some ‘sticky hitchhikers’ on our socks and trousers. The means by which they manage to attach themselves is simple and consists of small hooks that readily become entangled with the fur of mammals or the tiny loops of thread in the fabric of clothes. It was the microscopic structure of these diaspores that in the 1950s inspired the Swiss electrical engineer George de Mestral to develop the hook and loop fastener that we nowadays all know under the name Velcro®(based on the French velour = velvet, and crochet = hook). The ‘Velcro’ means of seed attachment is the gentle version and one very tenacious but harmless example is our native 'stickywilly' - also known as cleavers (Galium aparine).  

Galium aparine

Fruits of Galium aparine 

Other plants are less gentle and some are, in fact, rather sadistic when it comes to achieving the dispersal of their seeds.

Medieval weapons

One example, the so-called puncture-vine, is found in warmer parts of Europe where its diabolical insidiousness has earned the fruits of this little plant the name 'devil’s claw' or 'caltrop' (See Note:1 below for Wikipedia's definition of a caltrop).

Tribulus terrestris fruitsMSB Tribulus terrestris single fruit

 Puncture vine (Tribulus terrestris) fruits

The tribulation inflicted by the fruits on unwitting animals (and sometimes people) is even reflected in the plant’s scientific name (Tribulus terrestris). As the fruits of the puncture vine, a member of the Zygophyllaceae family, mature, they split into five ‘nutlets’. Each nutlet is armed with two large and several smaller spines. In whatever position the nutlets end up on the ground, some of their spines will always point upward, like a medieval caltrop, ready to penetrate the skin of an animal or even the soles of shoes. For example, on the Hungarian plains the prickly hitchhikers used to cause sheep farmers considerable trouble by inflicting suppurating wounds on their animals, which hampered their ability to walk.

Martynia annua fruit

Martynia annua mature fruit showing ferocious spines

Martynia annua showing fruits

Three mature fruits of Martynia annua showing their ferocious spines and with one fruit still with its soft green cover on it

Claws of the devil

Other ruthless and brutal examples of ‘devil’s claws’ occur in the dry tropical and subtropical semi-deserts, savannahs and grasslands of America, Africa and Madagascar. Like the fruit of the puncture vine, they bear sharply pointed spines, claws or horns which bury themselves into the flesh rather than gently ‘velcro-ing’ to the fur of animals.

The North American devil’s claws belong to species of the genus Proboscidea (esp. Proboscidea louisianica) and their smaller relative Martynia annua, and are both members of the Martyniaceae family.

Proboscidea louisianica fruit

Proboscidea louisianica mature fruit with its two sharp hooks widely spread ready to catch onto the hoof of an animal

In South America it is their carnivorous relatives in the genus Ibicella that produce very similar devil’s claws, or unicorn fruits as they are also called (e.g. Ibicella lutea). All of them have harmless looking green fruits which only reveal their true nature after their fleshy outer part has withered away. As the exposed endocarps dry out, their elongated beak splits down the middle to produce a pair of curved, sharply pointed, spurs turning the diaspore into a vicious contraption, poised to cling around the feet of hoofed animals and bore into their skin.

Grappling hooks

The old-world members of the sesame family (Pedaliaceae) honour their close relationship with the Martyniaceae by sharing the same ruthless concept of dispersal and produce even meaner traps. As the author can testify from his own experience, the fruits of the Malagasy genus Uncarina are undoubtedly the most tenacious fruits of all. With their radiating spines crowned by a pair of sharply pointed, recurved hooks, they not only rip into skin with great ease but are also impossible to untangle without using a secateur.

Uncarina species fruit 

Uncarina species showing spines and hooks

The most infamous member of the sesame family is Harpagophytum procumbens, aptly called grappling hook, grapple plant or, like its New World relatives, devil’s claw. Used as mouse traps in Madagascar, the almost preposterously horrid looking woody pods can inflict gruesome wounds to animals with cleft hoofs or relatively soft soles.

Besides being cruel, plants can also be fraudsters, as you will find out in my next blog.

- Wolfgang-

All above images by Wolfgang Stuppy and copyright Board of Trustees, Royal Botanic Gardens, Kew


Note 1: A caltrop consists of four spines arranged to point to the four corners of a tetrahedron so that however it falls, it will sit on three of the spines with the fourth one pointing up in the air. Caltrops were first used as a means to slow down pursuers on horseback but later proved to also work on pneumatic tyres in the motorised age. Iron caltrops were used as early as 331 BC at Gaugamela according to Quintus Curtius (IV.13.36). They were known to the Romans as tribulus or sometimes as Murex ferreus, the latter meaning 'jagged iron'. (from Wikipedia)



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Behind-the-scenes of the Jodrell

By: Jean Helliwell - 23 Apr 2012
Millennium Seed Bank volunteer Jean Helliwell recounts her recent opportunity to visit the Jodrell Laboratory at Kew.
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My name is Jean, and I have been a volunteer for the Millennium Seed Bank Partnership for three years, and a Friend of Kew for many more. I work at the Seed Bank one day a week cleaning seeds and doing germination tests. I thought the chance to tour the Jodrell laboratory was too good to miss.

On hearing of this tour, which was open to Friends of Kew, I immediately booked places for myself and my fellow volunteer Val (who has notched up some seven years’ service).

Photo of the Jodrell Laboratory at Kew

The Jodrell laboratories at Kew Gardens


The first stop on our tour was the Cytogenetics lab, where research is carried out into the chromosomal makeup of plants. It seems that there is a wide variation in the number of chromosomes in plants. A few plants have just two pairs of chromosomes (humans have 23) whereas others have many more. One plant (a fern) from India is reported to over a thousand chromosomes per cell.

DNA extracts and molecules

Next was the Molecular Lab. All the DNA extracts which Kew has produced are listed on a database available to all. In addition, the extracted samples are available to researchers all over the world, through the DNA Bank.

Another important area of research is in the identification of plant compounds that have medicinal potential. Some 70% of these are plant-derived even now, because they are either impossible or too costly to synthesise. A compound from the Madagascan periwinkle (Catharanthus roseus) has increased the survival rate in childhood leukemia from about 20% to more than 90% in little more than a decade, and there are many more beneficial compounds yet to be discovered.

Photo of a woman working on a microscope

Inside the Jodrell laboratory


Finally, we visited the Fungarium, which used to be called a Mycology Herbarium or Fungus Herbarium. However fungi are not plants - indeed they are more closely related to animals than plants! The oldest specimens date back to 1730, and some were originally collected by Charles Darwin.

All in all I found this a fascinating behind-the-scenes tour, and an insight into the importance to the community as a whole of the work done at Kew.

- Jean -

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About us

Staff at the MSB

The Millennium Seed Bank Partnership works with over 80 countries worldwide as we work towards our current goal of collecting and storing seeds from 25% of the world's wild plant species. To complete such a target requires a wide range of skills and expertise including training, research, seed processing, database management and fundraising.

There are five teams based at Kew's Millennium Seed Bank at Wakehurst in West Sussex. You will hear from all of us at some point through this blog.

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