Botany word of the month.

It appears that my intentions and reality do not mesh, yet again…a Botany Word of the Week is just simply too much for me to maintain on top of all my other projects.  But I love creating these posts and I hope you enjoy reading them – so I’ll switch to a monthly format which should be far easier for me to complete. We’ll see…intentions, you know….

Dehiscent

If you have a medical background, you’ll already know what this term means…except I’m going to use it in relationship to fruits.

When they are mature and dry enough, dry dehiscent fruit split open to release their seeds. Dehiscence is this act of breaking open at a seam. The part that splits is the pericarp (comprised of ovule-bearing structures of the flower called carpels).

The dry dehiscent fruit you are probably most familiar with belong to legumes.  Peas, beans, and lentils fall into this category.  They all have one carpel and if you’ve ever shelled garden peas, you’ll recognize the way that carpel splits open (except that you’re facilitating the split before it’s “supposed” to happen. When you allow peas to dry for harvesting, and they split open, then you’re letting them do their thing).

Do you remember this post I did a couple of years ago about the ‘Le Puy’ lentils I grew?  What I’m describing there is the explosive way the dehiscent fruit burst open when they’re ready.  And I’ll never forget the way that the seed pods of the Caragana shrubs that lined the driveway to my childhood home audibly crackled and violently burst on hot, late summer days, showering the seeds everywhere.

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‘Le Puy’ lentils…not yet dry enough to split open.

Peanuts are one dehiscent legume that don’t – thankfully – burst open when dry.   You have to help them along by breaking them open yourself.

There are always exceptions. Some legumes have indehiscent fruit, and their carpel does not split open when dry.  If you have a honey locust growing in your yard, that’s a good example.

Legumes aren’t the only dry dehiscent fruit.  There are capsules, which have more than one ovule.  Lilies and poppies have capsules.  There are also follicles, of which plants such as columbines have more than one.  Siliques are another.  These are a type of elongated fruit that kind of resemble legumes.  If you’ve ever allowed your radishes to set seed, that pod you’re looking at is a silique.  Just for fun, there are also silicles, which are not as long as siliques.  Honestly, I’m not making this up, even if it sounds a bit giggle-inducing.

What is your favourite dry dehiscent fruit to grow?  

 

Some links for further reading:

https://www2.palomar.edu/users/warmstrong/termfr1.htm

http://science.jburroughs.org/resources/flower/fruit2.html

 

Jicama: how to grow and cook it.

Another entry in my unofficial “unfamiliar tuber” series ;), Pachyrhizus erosus ‘Agua’ (jicama, also known as yam bean or Mexican turnip) graced my dinner plate for the first time last night.  Native to Mexico and Central and South America, and widely cultivated in the Philippines, Indonesia, China and southeast Asia, jicama is a member of the legume (Fabaceae) family and bears an edible root that looks sort of like a large brown turnip.  Peel the thick, dry skin away and you have a watery, starchy white vegetable that can be eaten raw or cooked.  The funny thing about jicama is that it keeps its crunchy texture no matter how it is prepared – it’s like water chestnuts that way.  It’s a bit on the sweet side, but I think you really need to marry it with other flavours to truly enjoy it – apparently in Mexico, it’s commonly served raw with chilies and a dash of lime juice.   I roasted mine in a little olive oil, with garlic, cracked pepper, and rosemary – yum!

As befitting a legume, jicama grows up to 5 metres long on twining vines, and can be trained to climb a trellis, or allowed to creep as a groundcover.  Blue or white flowers resemble those of peas, but to encourage the plants to direct energy to the production of roots, flowers must be pinched off.  (Bear in mind that all parts of jicama aside from the tubers are poisonous, so it’s necessary to wear gloves when deadheading.  The seeds actually contain a natural form of rotenone, a common pesticide ingredient).    Our northern Canadian climate isn’t warm enough to successfully grow jicama:  up to 9 months of sun, heat, and even moisture are required to produce decent-sized roots.  (“9 months of sun and heat” – sounds like the best tropical vacation EVER!).  Pachyrhizus erosus usually forms roots that weigh up to 2 kg; the ones you pick up at the grocery store normally hover around the half a kilogram mark.  (A record root weighing 23 kg was produced in 2010 in the Philippines by a related jicama species, Pachyrhizus tuberosus).

Give this refreshing taste of the tropics a go in your kitchen!

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See Garden Guides and Food Reference for more jicama fun.