Coralloid Roots

[Tracy]

Yes Cycads are descendants of some ancient plants.  They also produce those cool coralloid roots.  If you don't already know about them, I'll borrow some info I found in an abstract for a paper on them:

Cycads are the only gymnosperms and among the few plant lineages that evolved a specialized root organ to host symbiotic bacteria. Their lateral roots can develop into coralloid roots, a dichotomous and coral-like small cluster of roots, typically growing above ground, that acquire symbiotic bacteria (Norstog and Nicholls 1997). Its main function is nitrogen fixation for the plant (Bergersen et al. 1965; Grobbelaar et al. 1987), similar to the adaptive functions in legume nodules, but having appeared millions of years before them. In natural habitats coralloid roots appear in early life stages of the plant (Halliday and Pate 1976); and in adults mainly in habitats with poor or inaccessible nutrients, such as sand dunes, sclerophyll forests, steep rock outcrops with high exposure to salt, and lowland forests with recurrent fires (Grove et al. 1980; our observations). It is possible that coralloid roots and their bacteria are a key early trait that enabled cycads to thrive and adapt to changing environments during millions of years.

So I was out trimming some of the lower leaves off my Cycas thouarsii and noticed a big clump of corralloid roots exposed at the base of the caudex of one and decided to photograph and share them.  These aren't the only ones exposed in my garden, but it was a substantial clump of them.  Feel free to share any on your cycads and let us know which species cycad they are from.  At least one of the small pups on this female Cycas thouarsii is pushing out a new leaf in mid-winter.

 

[Tracy]

More coralloid roots popped up next to the emitter on this Encephalartos princeps.  A much smaller clump than on the Cycas above.

 

[Tracy]

Again, more coralooid roots popping up next to an emitter, but this time, I'm not sure which cycad is associated.  There are three in the neighborhood, an Encephalartos longifolius, an E eugene-maraisii, and probably the closest is a Cycas thouarsii x cupida  (center of photo with the other two off to the sides).  The emitter is actually for the Pseudophoenix which can also be seen in the photo.

[Tracy]

The Encephalartos eugene-maraisii does have some coralloid roots adjacent to its caudex shown below.

[NOT A TA]

15 hours ago, Tracy said:

If you don't already know about them, I'll borrow some info I found in an abstract for a paper on them:

Thanks for posting, I've learned something new today!

[Tracy]

Do you remember learning in pre-school that "sharing is caring"?  Well apparently one of my cycads adheres to that moto.  I was looking at the base of this Chrysalidocarpus decipiens which has split into four trunks over the years.  Do you see what I see at the base?  Yes, coralloid roots.  The question is which cycad's coralloid roots.  On the other side of the wall and a few feet away, there is a Cycas szechuanensis ssp fairylakea, but also nearby are Encephalartos lehmannii, Encephalartos longifolius and an Encephalartos natalensis x horridus.  I suspect I will never know, but hope that the Chrysalidocarpus decipiens is ok with sharing it's water and root space.

[gurugu]

That Decipiens could be called "multicaule". 👍👍

Now you have 4 palms instead of just 1.

Interesting to see in the future if "in group" look, is as nice as Archontophoenix 's. 

[Tracy]

9 hours ago, gurugu said:

That Decipiens could be called "multicaule". 👍👍

Now you have 4 palms instead of just 1.

Interesting to see in the future if "in group" look, is as nice as Archontophoenix 's. 

It is approaching 12 and a 1/2 years since I planted it from about a 3 gallon size, along with the Encephalartos longifolius and two Encephalartos natalensis × horridus in that planter.  It had already split into two growth points when I planted it.  The cycads were about 5 inch caudex and today all are similar in size.  The largest trunk may put out a leaf taller than the cycads when it opens. 

 I think all the splits have really slowed it down.   The general health of the cycads and extensive presence of corralled roots in the planter tells me they like the sandy soil which i amended to make the mounds with decomposed granite.   It's fast draining which is also good for the Chrysalidocarpus decipiens. 

[gurugu]

2 hours ago, Tracy said:

It is approaching 12 and a 1/2 years since I planted it from about a 3 gallon size, along with the Encephalartos longifolius and two Encephalartos natalensis × horridus in that planter.  It had already split into two growth points when I planted it.  The cycads were about 5 inch caudex and today all are similar in size.  The largest trunk may put out a leaf taller than the cycads when it opens. 

 I think all the splits have really slowed it down.   The general health of the cycads and extensive presence of corralled roots in the planter tells me they like the sandy soil which i amended to make the mounds with decomposed granite.   It's fast draining which is also good for the Chrysalidocarpus decipiens. 

Quite correct about them growing better in sandy soil. At least mine is doing so in sand after being trasplanted twice . I planted it 10 years ago in loamy soil but on a mound 5/10 cm above the surface, and that was what made the difference. Previously, I had planted two in loam too, but at surface level, and both died rather soon.