Cycad cone oozing from excess water

[Tracy]

My garden has seen an abundance of rainfall in the last couple of weeks.  I noticed something unusual happening with the male cone on my Encephalartos trispinosis.  It was oozing the clear fluid from the cone.  I have seen leaves or the caudex of cycads respond by oozing excess starch but this was the first time I observed it coming from the cone.  It prompted me to inspect what I could of the caudex and leaves for any additional signs of oozing, but it was limited to the cone.  Since it was raining at the time I noticed it I waited to go out into the yard until it cleared to take the photo and by then some of the liquid had either been reabsorbed or had just been washed away, as the photo doesn't show nearly as much as when I first noticed it.

While I know this is a normal behavior to see with either the caudex and occasionally the leaves, I'm curious if others see this with their cones from time to time in response to a lot of water.  I'm happy to say that at least I have a fast draining sandy soil so I'm not worried about anything rotting.

[tropicalb]

100% normal for cones as well as the caudex to oooze after heavy rainfall.

[Tracy]

We are in the midst of a wet spell like we haven't seen in a few years.  It is pretty normal, to see where I've trimmed cones off leaking but with all the rain, it is more than I would normally see.  The overall plant is fine, its just a little ugly where all that ooze has come out.  I have some dead shriveling male cones on a few cycads that I was tempted to cut off, but will wait now until I see I see a few days break in the rain.

[Merlyn]

I read something Sim Lav said the other day.  Apparently all cycads secrete a fluid that acts as kind of a wound seal.  I forget the name, it starts with a d?  This is normally on the surface of pretty much all parts of a cycad, but not really visible until it gets wet.  It absorbs up to 60x it's volume in water.  That"s the ooze you see, but it is not actually actively oozing.  Cycads will ooze the stuff in response to wounds.  He said you could test this by watering the hell out of a cycad in a pot, and it will not ooze any additional "stuff." 

This was news to me, I thought I would pass it along.

[GeneAZ]

I always considered it to be due to the barometric pressure change, since we have big storms here that produce no rain due to virga, and I'll get this mucillage appear around the event.  Virga is when it's so hot with low humidity that when it rains, the droplets evaporate before they hit the earth, and humidity doesn't increase much.

[Merlyn]

I found Sim's comment on it:

"Just like the myth that cycads produce mucilage to evacuate excess water when it rains....

Cycads produce mucilage to protect their wounds from external threats and one of this mucilage properties is that it has huge water retention properties. When it's dry, it's almost invisible, especially on the leaf bases, but when it rains it absorbs up to 60 times its own weight and becomes very visible, but it was there the whole time. This dry mucilage can stay for many years on the plant, even on very old wounds that have completely healed.

It's the wrong analysis of the observation that lead to that myth. And you can do the experiment yourself, take a cycad and put a hose with running water at its foot for 2 days to soak it as much as if it had rained: you will see no mucilage if you make sure you don't water the trunk itself. And you can also do the opposite experiment: protect the ground with impermeable plastic and put a misting system directly targeted to the plant's trunk and you will see that the mucilage becomes very visible after some hours.

Another fun experiment is to look for fairly recently cut leaf bases, scrape the dry mucilage with a knife and put it in a small bowl, add water and wait a few hours, you should get a fair amount of gel formed."

[Tracy]

On 1/14/2023 at 6:49 PM, GeneAZ said:

I always considered it to be due to the barometric pressure change, since we have big storms here that produce no rain due to virga, and I'll get this mucillage appear around the event.  Virga is when it's so hot with low humidity that when it rains, the droplets evaporate before they hit the earth, and humidity doesn't increase much.

Since what you are describing is a condition that does not involve actual water on the caudex, it seems to occur independent of what Sim has said above.

 

On 1/15/2023 at 6:25 AM, Merlyn said:

It's the wrong analysis of the observation that lead to that myth. And you can do the experiment yourself, take a cycad and put a hose with running water at its foot for 2 days to soak it as much as if it had rained: you will see no mucilage if you make sure you don't water the trunk itself. And you can also do the opposite experiment: protect the ground with impermeable plastic and put a misting system directly targeted to the plant's trunk and you will see that the mucilage becomes very visible after some hours.

Based on your observation Gene, there could be a combination of mucilage leaking from barometric changes and the expansive factor of the mucilage when it rains on the caudex, but if you are seeing it without rain, there is another explanation needed, which your barometric change assumption seems to address. 

What I have noticed is that some genus are more prone to producing larger volumes of this in my garden, particularly Encephalartos when compared with my Dioons, Cycas, Zamias, Lepidiozamias and Ceratozamias.  I did have this happen with no rain on my potted Encephalartos lehmannii  over a decade ago when I had it planted in a more conventional potting mix.  I ended up transplanting it into a pure pumice mix and graduated it up to a 15 gallon pot.  Ironically, it is one of the plants that still has the largest volume of mucilage visible after a rain event. 

[Merlyn]

I wonder if the accumulation of dew would make existing mucilage look bigger?  It rains so much here that I have never seen any except on a fresh cut.