Most climbing Aroids in MANY genera have juvenile forms that are
unrecognizable as being even related to the adult form, different shaped
leaves, size, shape and 'splits/divisions', etc.Some of the common ones sold
here in the USA would be species of Monstera, Philodendron, Syngonium and
the one under discussion.
You are correct that many plants are very different in appearance when young
vs. adult. I will continue my explanations in-between your questions
(below).
>>Thanks, everybody, for explaining about Epipremnum aureus (what I was
calling common pothos). Now about this "adult form" versus "juvenile form"
thing... I've also heard about this change in looks for common green vining
philodendrum (whatever THAT is really called).
And I think I've actually seen something like this sort of change in a very
unrelated houseplant, the thing sold as "aloe vera," so maybe this is not an
uncommon process across the vegetative world? Of course "aloe vera" doesn't
climb, but the change in appearance is very striking.
Let me review the process for aroids as I understand it, what we see growing
in the florist's little pot is a juvenile form that looks very little like
the adult. I sense from cryptic discussions I've read elsewhere that the
switch to an adult form requires at least a tall moist standard for the vine
to cling to and climb, plus copious amounts of sunlight.<<
Correct---I do not believe that except for a very few of the naturally
smaller species that growing indoors would work if you want to produce an
adult-sized specimen of any of these.
>>Please correct me on the above. Then, my questions (sorry they're so basic
but I would guess there may be someone else on this list who doesn't know
this stuff), for anybody to answer:
1) Does this happen only to vining aroids?<<
No. Other Aroids, even the low-growing terrestrial ones have both 'forms',
I have small Dracontioides that at this size have leaves with no 'holes',
and in a short while and when larger will produce larger leaves with many
holes all over the leaf blades. There are many more examples in the Aroid
world.
2) Besides lots of light, does this also require lots of heat and humidity?<
Yes. Monstera can grow in a 'drier' atmosphere, and that it why some sps.
make 'good' house plants.
3) So can this be done indoors under home conditions without a greenhouse?<
Not really, they will or may survive, but not 'happily'.
>>Can this be done in a greenhouse? Is this strictly for outdoors in
tropical
climates?<<
Yes---a BIG greenhouse!!
4) What actually are the basic trigger and mechanism of this change?<
When the plant encounters a suitable and tall-enough support, be it a tree
of rock cliff, etc it grows and 'changes' to its adult form. The actual
'trigger' for change from the adult form and also from seedling to adult is
a most fascinating thing to me, it is reported that the seedlings that may
germinate on open ground and the thin runners put out by adult plants on
overcrowded trees or other supports do NOT grow toward the light as in most
plants, but seem attracted to dark areas/shadows which may indicate the
presence of a new large tree or rock-face!!
5) What is the advantage of this change in evolutionary terms?<
A guess---the 'drive' to reproduce, and to do this the plant MUST reach
adult size, and to reach adult size MUST find a suitably large 'support'.
6) Is there a particular book that everybody else learned all this from
already?<<
Not all, but MOST can be learned from THE best book on Aroids available 'out
there', Aroids, by Deni Bown.
Thanks, and sorry if this seems like I'm quizzing you. I'm just kind of
stunned at the revelation that feral pothos can grow that big.<
It is such a pleasure replying to a beginner like yourself, and my hope is
that many others like you who may read this may become as enthused as I have
been and still am after all these years at these wonderful and mysterious
plants!
GOOD GROWING!!!
Julius Boos
WPB, Florida.
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