Catasetinae seedling behaviour question and few more things to discuss

[Jan Pahl]

In my garden I saw much but much more than once, a strange behaviour on Catasetinae (both Cycnoches and Catasetum), and since both genera represent the two phylogenetic branches of subtribe Catasetinae (one with Cycnoches-mormodes and basal Dresseleria, and the other with Catasetum-Clowesia), I have the felling all genera inside this subtribe shares the same odd thing...

The strange behaviour I am talking about is that sometimes the new born seedlings on my palms and rotten wood at my house don't develop their first pseudobulb were the seed rest, but on the contrary, the seed first develop a very thin but long rhizome that sometimes grows for more than a meter long before "stops" and develop the first pseudobulb. People that are following me knows that this early rhizome could be more white chlorophyll-less or green (with chlorophyll an even small speudo-leaves) depending if is growing inside the media or at open space.

This odd behaviour obviously is a response to seek and "find" a better place to grow, for example, once I followed for months the trail of one of those "early rhizomes" developing inside a dry palm petiole base, and the seedling rhizome at various points had "carved" the dry petiole to find a way to light and open air, and them "decided" that the point wasn't "correct" and buried again into the inner-petiole surface just to appear more downstairs until at some point, the rhizome "decided" to develop the pseudobulb at last. That behaviour is even possible to see on in vitro culture, as I saw on Brunos place.

my question is the following

this behaviour have a name?????
can someone can talk a little bit more about it????

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Another question I have (not related to seedlings) are the secondary "roots" that looks like "clustered upward filaments" (Holst call it pneumatophores) on adult plants. The thing is that in nature it is obvious that the early morning dry-season dew/myst concentrate on those filaments and them by gravitation it goes to the roots... Tthem.... why Holst says those filaments are pneumatophores?????...

Pneomatophores (like the word pneuma implies) are roots with "air supply" function like we find on mangrove and other swamp and damped areas plants... True pneumatophore roots are alive, and in Catasetinae this filaments are quite dead. Even if they weren't dead at all (which is not the case), those "roots" lack velamen, something quite necessary for photosynthesis on orchids roots (Vandas on the contrary have pneumatophores in the true sense on the word)

Since Holst is a smart guy much more informed on Catasetinae than me, I have the feeling that I misunderstood him because of his decision to use the word "pneumatophore" instead of another "technical" word for those modified radicular system... and for them my question in this matter is the following...could it be that Holst is not talking about air-aid absorption but about some sort of odd system that increase the velocity of air passing trough the filaments????... I mean, could it be that Holst have the idea that in this way Catasetums encourage somehow air circulation and for them avoid damp conditions fatal to the roots???

Since I am not in to aerodynamics, I really cant tell if the later could be the case... and about my observation about the dew collector system, it is based on observation only.

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The last question is why in the name of Jesus Christ Cyrtopodium and Galeandra are clustered outside the Catasetinae subtribe and clustered with less similar genera like Cymbidium and a large etc...

I am not botanist, nether I know Cymbidieae taxonomic clues for systematic and nether known almost anything about resent phylogenetic studies on the subject, but I like to learn and for them I ask.... someone can explain to me please why in this case a "Lion" shares more affinity with "Lynx" than "panthers"?... It have to be a reason that explain this """parallel evolution"""

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Jan

[Gena]

Jan, if I understood correctly than there are different theories about pneumatophores. Holst mention one of them, namely aeration of the compact root mass of the plant. Did you notice that pneumatophores did not emerge when roots are young? Only on the older ones.

[isurus79]

Your first question sounds like something that really needs to be investigated! I think this would be a good project for a PhD student. You don't have any pics do you?

As for the aerial roots, I always (from Grammatophyllum growers) that these roots are used to capture detritus and other leafy plant material. These roots are supposed to act like a 'net' to collect dead leaves and stuff as an extra source of fertilizer. Some of my Stans have these roots, my Gram scriptum has really big air roots and some of my Catasetinae. What I want to know is why do some plants put out these roots in different years and none of these roots in other years?

As for the Galeandra and Cyrtopodium question, you are on your own with that one! Taxonomists are nuts in my opinion! jk

[Jan Pahl]

Originally Posted by Gena

Jan, if I understood correctly than there are different theories about pneumatophores. Holst mention one of them, namely aeration of the compact root mass of the plant.

Well I know about the "debris" collector theory that I forget to mention and is true, many fallen leaves get trap on those pneumatophores, also I saw it serves very well to collect morning myst/dew as I previously mentioned.... but the aerial function intrigues me because I don't know if air pass more rapidly through the root mass if those pneumatophores are present.... I hope that someone with more experience with aerodynamics cold tell us if a "forest" of "poles" increase air velocity

Originally Posted by Gena

Did you notice that pneumatophores did not emerge when roots are young? Only on the older ones.

Yeap, good point that you mention it...

[Jan Pahl]

Originally Posted by isurus79

Your first question sounds like something that really needs to be investigated! I think this would be a good project for a PhD student. You don't have any pics do you?

sorry , don't have but maybe I can start to document that... Bruno have many ideas of how to cultivate Catasetum based on how they grow in the wild, I have to chat with him about the possibility of start to record related stuff.

Originally Posted by isurus79

As for the aerial roots, I always (from Grammatophyllum growers) that these roots are used to capture detritus and other leafy plant material. These roots are supposed to act like a 'net' to collect dead leaves and stuff as an extra source of fertilizer.

... and that is 100% true, I forget to mention it before. Thanks for quoting it.

Originally Posted by isurus79

What I want to know is why do some plants put out these roots in different years and none of these roots in other years?

Well the best source I have are wild macrocarpums... in some parts near Caracas (specially were humidity is very low on dry season), large quantities have those neumatophores, Inside Caracas you can find seldom and even plants growing together one with and one without those aerial roots.At my House, but also in other very humid places (low and highland)), no macro develop those roots... If I have to say, these behaviour is very attached to humidity in dry months. Same thing with Cytopodium from Caracas and surroundings.

Originally Posted by isurus79

As for the Galeandra and Cyrtopodium question, you are on your own with that one! Taxonomists are nuts in my opinion! jk

Yea!!!!!!