Amphicarpaea - The Talented Mr Talet

A while back I made clear my suspicion regarding plants with animal prefixes like pig, horse, dog and so on.  The implication is clear:  they're food  fit for dogs, hogs and horses, not humans.  Horses, dogs and hogs are all thoroughly worthy animals, but, generally speaking, although they may want our food, we tend not to want theirs. 

I am now about to break my own rule, but like a proper merchant banker I shall retain a clear conscience, if not a six figure bonus.   Amphicarpaea bracteata is the hog peanut, a widespread North American legume with a fascinating reproductive system. Of more immediate interest is its production of tasty underground beans, 
which can be harvested in the autumn.

In order to circumvent my own rules, I have therefore unilaterally elected to rename Amphicarpaea bracteata  "talet" rather than "hog peanut".  First of all, it's not a peanut, Arachis, although it does form underground pods. It's recognisably a bean. Secondly the beans  are definitely worth fighting over with the hogs. A pod isn't a root, as avid botanists amongst you will have already spotted;  this is assuredly an egregious deviation from my mission statement, but just as the first potatoes in Europe were thought to be truffles, I consider hog peanuts to be an honorary root crop. They do grow underground  in a rootlike way and are sometimes even erroneously referred to as tubers.   

So why talet you may ask?  Talet is the name given to the hog peanut in the milpas (traditional cornfield polycultures) of the Sierra Norte de Puebla, Mexico, where it is semi-domesticated, or, perhaps more correctly, an encouraged weed.   Seeds are sown with the corn and then harvested and toasted on a skillet when the fields are ploughed at the end of the season.   

Surprisingly, perhaps, they seem to grow quite well here.   The plants have trifoliate leaves and look a bit like mini French beans. They're actually rather pretty in an understated sort of way.   This photo, courtesy of Frank van Keirsbilck , provides an impressionistic sweep of talet foliage.  

The shoots will climb up any stems in their vicinity and after a while, long horizontal side branches power out from the leaf axils.  These produce thin stalks, like long antennae, that burrow into the ground. At their tips are tiny flowers  and each one has the potential to form a bean. These flowers are cleistogamous, that is they never open and are self-pollinated.  At the same time, all unbeknownst and invisible, similar shoots are developing underground straight from the parent seed. 

Later in the season the aerial flowers appear, first in the form of single cleistogamous flowers, which may go unoticed and somewhat later still  as small clusters of open- pollinated (chasmogamous)  flowers, with pale lilac petals.  So that gives the plant a range of seed types:  soft fleshy ones underground from the cotyledonary shoots, similar ones from the long aerial side shoots, both of which are self-pollinated.  Then there are the small hard seeds from the aerial flowers, some of which are self-pollinated and some of which  are open-pollinated.   In a good season the big seeds will survive until the following spring and produce big plants.  If things get a bit tricky, the small hard seeds will probably make it through until conditions improve again, perhaps several years later.   They may get carried some distance from the original plants during this time.   Their genetic variability will show up in the seedlings, some of which may be better suited to the prevailing conditions.  If they like what nature dishes up, they'll produce lots of the big seeds once more.  The technical term for this botanical bet hedging  is amphicarpy.   If you understood any of that, well done.  I think I'll go and lie down for a bit. 

Another advantage of Amphicarpaea is its abilty to fix nitrogen.  The correct strains of Rhizobium bacteria for effective nodulation  belong to the "cowpea miscellany" (weren't they a progressive rock band circa 1976?).  These tend to be absent from British soils, so I just plucked some nodules from my Apios plants, crushed them in water and poured them over the Amphicarpaea plants. It seemed to do the trick with lots of nodules developing afterwards.  

There's a closely related species in Asia, Amphicarpaea edgeworthii.  The Japanese, who leave no stone unturned when it comes to testing things for edibility, have even investigated it as a potential crop plant.  The Japanese name, "yabumame", means, apparently,  "bush soy", which is suggestive of innate potential.    I had to laugh when I saw a plant growing, oh-so-nonchalantly, right outside the dormitory building in Tsukuba,  Japan where I stayed for a couple of weeks  in 2007.  It was even funnier to step into the greenhouses and see, wholly unexpectedly,  oca, ulluco and mashua plants, but that's another story.  
I can see talet being grown as a living mulch around root crops, like, oh, I don't know, oca for example, or in a modification of its Mexican cornfield  habitat, as a ground cover in a sweet corn patch.   At the moment it expends a lot of energy producing long runners that deposit seeds far and wide.  Maybe with selection, varieties with shorter runners and bigger yields could be obtained.   The abstracts of Japanese papers I've read on the subject seem to suggest this. 

Although the plants themselves are frost tender, I have frequently noticed seedlings popping up from unharvested seeds the following May.  A tasty underground legume that can actually survive here and emerge in spring - that's no peanut.

Talet apparently needs short days to initiate flowering.  As  A. bracteata occurs right up into Canada, it's possible that varieties better suited to our long day summers might be found there.  Anyone who can provide me with seeds from such northerly locations will earn my undying gratitude and an honourable mention on the blog. 

OK, the yields are unimpressive, but this a wild plant.  Compare your average King Edward with a wild potato progenitor, say, or a wild carrot with a nice juicy Chantenay Red Core.  It's unlikely they'd be mainstays of the British diet had they not undergone rigorous selection for size and taste.   No, in my opinion, talet has definite potential. Accentuate the positive: tasty bean, grows well; eliminate the negative: low yield, daylength sensitivity and do mass selection in between.

Another interesting observation, which could be advantageous, is that, in my experience, talet doesn't want to bake in the sunniest spot in the garden.  Plants in full sun seem altogether dejected and yellow.  Give them a bit of shade and they're big and vigorous.  A shade tolerant, nitrogen-fixing bean crop that grows in Britain - Gimme! Gimme! Gimme!  Apologies to ABBA, but who'd want a man after midnight when they could spend the preceding few hours munching on handfuls of delicious talet beans from their own polyculture plot? 

Double the yield, reduce the excessive vigour and we might just have a really useful new temperate legume crop.  What are we waiting for?


Catofstripes said…
Thanks, new and interesting stuff.
Anonymous said…
Perhaps some research into lost psychedelics of the America's? Surely there's someone in the UK who's experimenting with home brew Ayahuasca? Sounds like more fun than yeast and barley malt.
my names Lou and a friend of yours (Pauline) gave me your blog address as i am searching for ulluco tubers at the moment. Laughed greatly at you descriptions of their taste and viability,now enjoying reading all your other blogs!Both informative and amusing . I'll be adding hog nuts to my list of "must have's". If you ever manage to find anymore ulluco please let me know (cheesy grin)
Thank you for a damm good read.
yours Lou
Rhizowen said…
Hello Lou

Thank so much for your very kind comments. Please be aware that you are now entering a twilight world of obsession, scruffy parcels and shrivelled tubers of dubious provenance. Just like Ebola virus and the Boogie Disease, this thing is contagious, very contagious: "Thought I'd boogie to the doctor, boogie to the nurse; Gonna keep on boogiein' till they put me in the hearse."

Good luck

Ottawa Gardener said…
May I saw that I love your blog and now, I am on the lookout for some of these (did I already buy some?) but if I get ahold of some Canada born seeds, I'll be sure to send you some.
Thank you so much Owen! sorry for the delay in replying, im afraid i was busy with scruffy envelopes of dubious origin! :)
I was talking to Niel (HSL) the other day & he mentioned that Mashua,Oca an ullacoo were held as part of the collection a while back and were unfortunately lost due to overwinter storage problems (& virus weakness).
i'll let you know how i get on, ive got shoots already! getting excited!!
cheers lou x
Mark said…
Your blog is excellent. Nice to know that other people love plants as much, and tubers especially.
Rhizowen said…
Thanks Mark for your kind comments

It's always great to hear from others who share passion.
Mark said…
Just tracked down some interesting info regarding rhizobia for this species. It requires a certain kind of rhizobial symbiotic bacteria (specifically Bradyrhizobia)and it must produce a type of chemical called rhizobitoxine. This seems to cause chlorosis in soybeans. So that could be an amswer to low unimpressive problem find sick soybeans with cholorosis get the soil and you may have healthy productive Amphicarpaea. Could be useful information, in case low yields cause you to forget about this crop.
Mark said…
Have tracked it down, the inoculum must be a species called Bradyrhizobium elkanii. The United States Department of Agriculture stocks inoculum numner USDA61 this prduces the right growth hormone rhizobitoxine. No idea whether you can just ask them to supply some or what.
Rhizowen said…
Interesting . My hog peanut plants seem to nodulate OK with either nodules from Apios, or from the soil from previous Amphicarpaea experiments. Matthew Parker told me that he believes the North American hog peanut consists of two species with slightly different morphologies and (if I remember correctly) rhizobial symbionts. Apparently Bradyrhizobium elkanii doesn't work on Amphicarpaea edgeworthii, the Asian species, which i grew for the first time this year. As it spent its life in intensive care on the windowsill, I didn't get round to inoculating it.

As we all knew, the only good soybean is a sick soybean.
Mark said…
Glad that is sorted out. Matthew Parker was author of some of the key refs I tracked down. So he ought to have some idea. Wonder what rhizobia A.edgeworthii uses?