Village Green Plant Swap

On 21 October 2018 there will be a plant swap at Village Green.  I plan to attend!  There are lots... and lots... of plants that I'd like to share with others.  The question is... which plants are people interested in?  I'll post potential plants in this entry and in the Village Green Thumbs (VGT) group.  If you would like me to bring a plant for you then please let me know!

Seedlings

When I sow seeds I usually sow the seeds of a few different plants in the same pot.  This hedges my bets that something will germinate.  Usually there's decent germination so pretty much all the seedling pots will need to be divided.  The expectation is that people who receive a community pot (compot) will share any extra seedlings with other VGTs.  There's also the expectation that updates on the seedlings will be shared in the VGT Facebook group.  It will be very interesting, and informative, to see how much variation there is among the siblings.

Hoya Seedlings

These seedlings are from seeds that Tom gave me when we visited him in August.  I sowed the seeds on 15 Aug.  Here's a pic of the mother plant's buds, leaves and seeds...

Hoya Seeds

Here's a pic of the flowers...

Hoya Flowers

Does anybody recognize it?

Each pot might have the following seedlings...

Vriesea - John Arden hybrid (seeds from Sarah)
Anthurium schlechtendalii (seeds from Sarah)
Echeveria rosea

Columnea Elmer Lorenz

Not sure what its "real" name is... maybe it's Columnea crassifolia?  The leaves are certainly very succulent... for a Columnea.  My plant mentor Elmer Lorenz gave it to me several years ago and I've been really happy with it.  This epiphyte is exceptional because it stays in bloom for almost the entire year.   My friend Dave says the same is true of Columnea schiedeana.  I wonder which one would grow the best epiphytically.

Mixed Seedlings 5 Aug

I have 5 hanging baskets/pots that might contain the following seedlings...

Anthurium schlechtendalii (from Sarah)
Begonias cane type including Mabel's front porch (from Chris)
Echeveria ballsii - might be crosses with Echeveria macdougallii
Echeveria rosea
Kalanchoe uniflora
Orchid - most likely reed stem Epidendrum
Sinningia cardinalis - might be crosses with Sinningia leucotricha (from Michelle)
Vriesea - John Arden hybrid (from Sarah)

Quite a few of the seeds still haven't germinated. 

Mixed Seedlings 9 July 

I have 12 pots that might contain the following seedlings...

Begonia NOID

Begonia thiemei/carolineifolia (from Fernando)

Bletilla striata (from Fernando)
Echeveria (gibbiflora x rosea?)
Fern gametophytes/sporelings (from Monica)
Ruellia brevifolia
Ruellia elegans

More seedlings to follow!  Watch this space and the VGT Facebook group!

Plants

Lemmaphyllum microphyllum

This miniature fern from Japan is growing on a big bunch of New Zealand Sphagnum moss around three stories up on my tree.  Here's a closer pic...

I have 18 pots with small divisions of this fern.  The pots might also include small seedlings of the following...

Sinningia piresiana (my favorite Sinningia)
Vriesea John Arden hybrid (from Sarah)
Aloe hybrid (distans x bainesii?)
Aloe pluridens (maybe crossed with variegated arborescens)
Aloe nyeriensis (maybe crossed with kedongensis)
Aloe kedongensis (maybe crossed with nyeriensis)

The pots might also contain gametophytes of the following...

Dicksonia antartica
Cyathea australis
Blechnum nudum
Todea barbara
Lemmaphyllum microphyllum
Microsorum punctatum

The spore from the first four are from Laura and Patrick.

Begonia NOID

I grew this from some really old seed... does anybody recognize it?  You can't quite tell from the photos but the leaves and stems are kinda fuzzy.  I refer to it as my "Burnt" Begonia because it grew from its seedling pot into the lamp and its leaves would get singed.

Aloe cameronii

If it gets enough light this Aloe will color up nicely when it's cold/thirsty.

Tillandsia albertiana

It doesn't seem like there are many Tillandsias with red flowers.  In the pic you can see Tillandsia albertiana blooming on my tree.  When I visited Pat he shared a nice big clump with me, so I have extras available if anybody is interested.


More plants to follow!  Watch this space and the VGT Facebook group!


Cuttings

Plants that easily grow from cuttings are the best.

Kalanchoe uniflora

My favorite Kalanchoe!

Clerodendrum ugandense

Also known as Rotheca myricoides 'Ugandense'.

Solandra maxima

Commonly known as the Cup of Gold vine.

Epiphyllum oxypetalum

If you pollinate the flowers they will produce a fruit that is a little smaller than a dragon fruit.  Also, the flower petals are edible, they can be used for soups or salads.  The plant itself does not have any spines.

Selenicereus macdonaldiae

This climbing cactus produces what might be the largest cactus flower.  The stems have spines on them.

Hylocereus costaricensis

Dragonfruit!  This variety has red flesh.  The plant has spines and wants to climb.  Needs sun.

More cuttings to follow!  Watch this space and the VGT Facebook group!


Seeds

Delicious Epiphyllum

Julia shared an Epiphyllum fruit with me and it was so tasty that I very reluctantly decided to stop eating it and save the seeds. 

Pink Plumeria Tree

Scadoxus took this photo of a big Plumeria tree at Gary's place.  She happened to spot a seed pod which he gave to me.  I've sown a few of the seeds and they germinate pretty quickly.


More seeds to follow!  Watch this space and the VGT Facebook group!

Coherent Communities

In the thread that I created about growing succulents epiphytically, Stan replied and asked me about living walls.  Naturally I thought about my friend Erik Van Zuilekom.  He lives in Melbourne Australia and designs living walls.  We met on Flickr in 2013 when he sent me a private message asking me about watering the plants on my Cedar tree.  Here's his Flickr page. 

Erik and I are also friends on Facebook but it's been a while since I've checked out his personal page.  Recently I did so and found this pic...

Here's what he wrote...

Rainy day image. Rarely do I grow a single plant in a pot. Companion planting holds secrets. As I observe these species in habitat, it’s evident evolution is not about the individual, rather responses to relationship. Bromeliads collect water that overflows to their root base, where mosses and hepatics grow, further stimulating seed germination and eventually the influx of vascular plants.
The community of species is more resilient than the individual. - Erik Van Zuilekom

Exactly!

Thanks to this thread in the forum for Epiphytic Myrmecophytes, I learned that Stone Jaguar created a website... Exotica Esoterica, which contains many treasures such as this Bonsai Diorama.  I first learned about his exquisite companion planting when he shared it in this thread of mine in the Agaveville forum. 

What's the difference between grouping people and grouping plants?  In both cases, some combinations are certainly better than others.

Here's a pic of my tree in 2011...

The tripod is there because I was trying to take a picture of the orchid seeds that germinated on the bark.  You can see that the rabbit's foot fern (Davallia) was making its way to the sunny side of the tree.  At that point I think it had already smothered, and killed, a couple of orchids so I ended up removing it completely.  The variegated Monstera hadn't killed any of the other plants... yet... but it was quickly taking up more and more space that could be used by a wider variety of plants.  I didn't remove it entirely but I did remove the portion of the stem that was in the ground.  This slowed it down... and it survived for several years... until the drought caused me to reduce summer watering of the tree from 3x to 2x a week at night.  This was the last straw for the Monstera.

In this short-time lapse video, you can see Jerry, Gene, Fernando and I removing a Monstera from the base of Jerry's big Catalpa tree.  This freed up a lot of space that could be used to grow a wide variety of other plants.  The same thought came to mind when this past weekend I saw Gary's Jacaranda tree covered in monstera...

It's a matter of getting the balance right.

One of the most important parts to get right for companion planting is the host.  Pretty early on in my epiphyte experimentation I cut some large branches which I suspended and attached numerous orchids to.  The branches lasted for several years but eventually they deteriorated and the orchids had to be removed and remounted.  It's convenient to be able to use large hanging branches... so what's the solution?  What about Ficus?

Here's a companion planting that I created on Aug 16 this year...

It's a largish branch from my Cedar tree that has the following plants attached to it...

Ficus thonningii
Kalanchoe uniflora
Microgramma vaccinifolia
Platycerium willinckii (from Barbara Joe)
Worsleya procera (from Dave)

The Ficus was a well-rooted cutting that had been happily growing in a pot.  I removed it from the pot and washed off the dirt from its roots.  Next I tightly attached it to the Cedar branch and added quite a bit of New Zealand Sphagnum moss around its roots which I covered with shade cloth.  I stapled the shade cloth closed and cut a square on one side where I placed the Platycerium.  Not sure if it was necessary to remove a portion of the shade cloth... I'm guessing that the Platycerium would have rooted through it.  Before using fishing line to attach the Platycerium, I placed the Kalanchoe, Microgramma and Worsleya partially behind it.

I suspended the branch in the small area that I water most frequently and the Ficus pretty quickly started growing new roots.  Here, if you look closely, you can see one just starting to poke through the shade cloth...

The Kalanchoe roots, on the other hand, are going in the opposite direction.

So far the exposed Ficus roots have been "air-pruned"... but more and more of them keep poking through the shade cloth.  How much progress will they make over time?  Will they be the root equivalent of stalactites?  For those of you who still haven't seen it, the Ficus thonningii at the LA Arboretum has by far the best aerial roots of any tree in California. 

What will happen to the Worsleya procera?  It's a super nice, and quite expensive, bulb.  Dave was really generous to give me two seedlings that he grew from seed.  I put each one in pretty much pure pumice.  So far they've both been very slow... but one is faster than the other.  Somehow, even though it was on a second shelf, some cats managed to knock over the slower one.  I decided to give it more peat... and it seemed to respond to the additional moisture... but then I started getting nervous about it not having enough drainage during the winter.   When I unpotted it for inclusion in the companion planting, I noticed that the roots didn't look so great.  Now it gets frequent water but the drainage is excellent.  Not too long ago a new leaf started to emerge.   It might be because of the moist moss... or maybe it's because it now gets a lot more sun... as you can tell from the photo.

One potential problem is that the Ficus roots will quickly "use up" all the moss and not leave any for the Worsleya.  The two ferns will slowly make new medium but I think the Ficus will probably compete it away from the bulb.  The bulb would have faced even more competition for limited medium if I had included an orchid.  But there are some orchids that aren't very vigorous rooters so I might add one or two of those.

The Kalanchoe can get by without much medium.   Check out Erik's Kalanchoe uniflora.  Wow!  I wonder how much medium it has. 

By the time the Cedar branch starts to fall apart... will the Ficus branch be developed enough to carry the community?

The next month, on 20 Sept, I created another Ficus-based mount for the piece of Vanilla that Julia shared with me.  I met her through the LA/OC trading group on Facebook.  She easily has the biggest house-grown Vanilla that I've ever seen.  Here it is outside...

Here's the piece that she shared with me...

Here's a context photo...

The branch was freshly cut from my Ficus lutea tree.  To get the moss to stay on the branch I covered it with shade cloth which I stapled to the branch.  Here's what I included in this planting...

Aloe bellatula hybrid? seeds (from Julia)
Aloe Lavender Star seeds (from Julia)
Aloe tabletop NOID seeds (from Julia)
Ficus rubiginosa (from Julia)
Kalanchoe uniflora (one mine and the other from Sarah)
Microgramma vaccinifolia
Vriesea John Arden hybrid seeds (from Sarah)

Julia has a big beautiful Ficus rubiginosa tree that has aerial roots growing from relatively small branches.  She gave me a good-sized branch with lots of aerial roots.   I divided the branch so that each stem had aerial roots.  Here's one example...

Even though the divisions had plenty of aerial roots which were in plenty of New Zealand Sphagnum moss that I watered every night, the stems lost their leaves and appeared to desiccate.  My guess is that I cut the rooted portions of the branch too short.  : (   However, Julia also gave me plenty of seeds from her Ficus so I can sow those on the mounts.

Which Ficus would result in a better balance... thonningii or rubiginosa?  Chances are good that some other Ficus would be a better companion/host.  Recently Gene gave me some cuttings from three of his Ficus.  Hopefully they will root and I can experiment with them.

The Ficus lutea branch is still alive so there's a chance that it will root into the moss.  So far the Vanilla hasn't started to grow but it's perfectly turgid, thanks to the few aerial roots that it has in the moss.  Now really isn't the best time of year to try and get a Vanilla established outdoors.  Plus, the commercial varieties aren't big fans of our winters.  Back in Dec 2014 I was pretty surprised to see this Vanilla happily growing on some wood in Dave's patio (he lives in Eagle Rock)...

You can see in the foreground the main plant that was potted.  Dave wasn't exactly thrilled with having the Vanilla climbing where it was... so maybe he tried moving it?  Or maybe the cold deterred it.  In any case it is no longer there.

So far it seems like the best Vanilla for growing outside in SoCal is Vanilla chamissonis.  Here it is growing on Jeff's house in Echo Park...





That pic was taken in 2011... not sure whether it is still there.  The SBOE has this species for sale.

I have no idea how many different "clones" there are of the commercial variety of Vanilla... but there's going to be some variation in cold tolerance.  Maybe Julia's Vanilla is more cold tolerant than most?  Maybe it isn't.  Then again, maybe a mounted Vanilla would do better over winter than a potted one.  I might bring the mount inside or give it to somebody with a greenhouse.

The day after creating the Vanilla/Ficus mount I created an Aloe/Ficus mount...

On a freshly cut branch of Evergreen Pear (Pyrus kawakamii) I added the following plants...

Agave - very sad plain green miniature
Aloe bakeri
Aloe bellatula hybrid? seeds (from Julia)
Aloe ‘Carmine’
Aloe - hanging (from Geoff)
Aloe Lavender Star seeds (from Julia)
Aloe - miniature green lineata
Aloe - miniature green rounded
Aloe - semi-pendulous (from Elmer)
Aloe - tabletop colorful
Aloe - tabletop NOID seeds (from Julia)
Aloe - tabletop white (x 2)
Gasteraloe? - slender leaves (x 2)
Ficus rubiginosa
Ficus thonningii
Pyrrosia - nice one from tree fern

The Pyrus might root into the moss... but I doubt it.  The Ficus rubiginosa hasn't fared so well but the thonningii quickly established, even though it only had a few short roots on it.

For some reason the Aloe seeds haven't germinated yet.  Or maybe they have... but they are still inside the shade cloth? 

Usually I sow different seeds together.  For example...

There are seedlings of Bletilla striata and Begonia thiemei/carolineifolia from seeds that I received from Fernando.  I sowed them in July of this year.  If anybody local is interested in having one of the nine pots with these seedlings, I can bring them to the upcoming plant swap at Village Green. 

Right now the Village Green Thumbs group on Facebook has 7 members.  It has the potential to grow and produce some very exciting companion plantings. 

Update On Orchid Seeds That Germinated On My Tree

On the OrchidBoard, Camille1585 requested an update on the orchid seeds that germinated on my tree.

************************

In 2011 I sowed a bunch of different orchid seeds on my Cedar tree and much to my very pleasant surprise some of them actually germinated...




All the seedlings turned out to be Laelia anceps.  Over the years I've documented the growth of the largest seedling...

December 2012




June 2013




Dec 2013




Aug 2014




Nov 2014




April 2016




June 2018



There's a really big disparity between the seedlings in terms of size.  Here's one of the smallest seedlings...

What explains the remarkable size disparity?  Is it because of the difference in the seeds and/or the difference in the microhabitats and/or the difference in the helper fungus?

The largest seedling germinated right next to the roots of a slow growing variety of Dendrobium teretifolium.  Evidently the Dendrobium harbored a fungus in its roots that the Laelia seed was able to put to good use.  Is this fungus from Australia like the Dendrobium, or from Mexico like the Laelia, or is it pantropical?  In any case, given that the Laelia is in the process of outgrowing and overgrowing the Dendrobium, clearly it isn't always advantageous for an orchid to harbor fungus that can help germinate the seeds of unrelated orchids.   I wonder whether the seeds of this Dendrobium would be able to germinate near the roots of this Laelia.

Right now the largest seedling has five new pseudobulbs starting to grow.  In many, if not most, years its pseudobulbs mature around August and new ones would start to grow.  They would mature late winter or early spring.  Part of the reason for this is because this individual hasn't yet allocated any energy to blooming!  It is definitely not precocious.  The trade-off between growing and blooming is quite interesting.

Last year I removed two keikis from my very wonderful Dendrobium Gloucester Sands (discolor x canaliculatum) and attached them to boards...

The smaller keiki decided to put out roots and a new pseudobulb while the larger keiki decided to bloom.  Blooming is very costly in terms of energy so, for a plant this size, I'd normally nip the spike in the bud, so to speak.  In this case I decided to leave it for illustrative purposes.  Some animal decided to mostly override my decision by eating all of the buds except for one.

The "pockets" made of shade cloth are filled with slow-release fertilizer granules.  This effectively fertilizes all the mounted plants beneath it, but I really shouldn't have attached the pockets to the boards.  Bundling the pockets and the boards discourages me from moving the boards.   Instead, I should have made completely "independent" pockets.  Another thing, seedlings and small newly mounted divisions don't respond well to lots of fertilizer.

Getting back to the Den Gloucester Sands, here are its roots growing on my Pachypodium lamerei...





Here's a video of it...





Diversity is the best.  Last September I excitedly purchased a flask of Bc Beulah Bradeen (Cattleya walkeriana x Brassavola nodosa) from eBay.  Both parents have done quite well for me so I was very curious to see whether their offspring might do even better.  As per my standard operating procedure, I carefully mounted the largest seedlings on sections of trellis wood...

I distributed all the mounts throughout the garden.  So far only around five seedlings survived the winter.  And it was a pretty reasonable winter... it didn't even freeze.

Why did so many seedlings die?  Was it primarily from a lack of heat?  Or was it primarily from a lack of water?  During winter, for most of my plants I drastically cut back on watering.  In any case, given that a few seedlings survived, there's certainly variation in terms of the seedlings and/or the microhabitats.

One issue with flasks is that there's usually no selection in terms of drought tolerance.  Last fall I had a relevant e-mail discussion with an orchid hybridizer in Australia who specializes in tea tree orchids.  He had recently registered Dendrobium Ultraviolet, which is a cross between a less succulent orchid, Den Berry, and a more succulent orchid, Den canaliculatum.  Even though the cross is 62.5% canaliculatum, it looks more like kingianum.

My theory is that, in a flask with adequate moisture, storing water is a disadvantage.  Seedlings that are more succulent are going to lose the competition for limited space to the seedlings that are less succulent.  So when a more succulent orchid is crossed with a less succulent orchid, if the seeds are flasked, then the seedlings will be less succulent.

I think the same concept must be true for temperature.  If a cooler growing orchid (ie Den Berry) is crossed with a warmer growing orchid (ie Den canaliculatum), and the flasked seeds are kept cooler, then the seedlings will predominantly be cooler growers.  I doubt that any professional flasking laboratories expose their flasks to temps as high as the temps that Den canaliculatum experiences in its native habitat.  Basically, the deck is stacked against Den canaliculatum's warmer growing and drought tolerating traits.   

Orchids populations, like all populations, conform/adapt to their conditions/environment.  Here's the most relevant passage that I've found on the general topic...

An ovule is successfully fertilized by only one pollen grain out of (potentially) many thousands.  If fertilization is performed at a sufficiently low temperature, the growth of chilling-resistant genotypes of pollen will be favored over others.  These will reach the ovule first so that their genes will appear in the resulting seed.  At no other stage of development can selection be made on such large numbers of genotypes. - Brad D. Patterson and Michael S. Reid, Genetic and Environmental Inlfuences on the Expression of Chilling Injury

What's very interesting to consider is what happens when an orchid is pollinated during the spring or fall here in Southern California.  A few days ago the high temps were in the low 90s.  Now the highs are in the low 70s.  That's a pretty big range of high temps.  Imagine how much impact this fluctuation would have on the race for the ovule.  In theory the most hercuthermal genotypes should win the race.

Laelia anceps generally blooms from fall to spring... depending on the plant and its conditions.  Honestly I don't even remember pollinating my Laelia anceps.  For all I know the seeds that germinated on my tree were from a Laelia anceps owned by unknown neighbors.  But in terms of adapting to SoCal's climate, it is advantageous for Laelia anceps to bloom when it does.  Unfortunately, its blooming also coincides with my break from my plants.  I think that, after the seeds germinated on my tree, I only once tried to pollinate my anceps, but no pods developed.  Evidently the pollen that I used (ie Brassavola) was too different.

There have been a few other times when I sowed other orchid seeds on my tree.  Only one of these other sowings was somewhat successful...





I noticed this NOID seedling in 2016.  It germinated right next to the roots of a Vanda tricolor.  I looked around and managed to spot a few other similar seedlings in the vicinity.  It is definitely a sympodial orchid and its pseudobulbs and the undersides of its leaves are burgundy.  When Camille1585 asked for an update on the Laelia anceps seedlings, I climbed the tree and noticed that one of these NOID seedlings was about to fall off because somebody, probably a squirrel, had dislodged the piece of bark that it was attached to.  I carefully removed the seedling and attached it to a board...

If you zoom in you can see a bunch of reed-stem Epidendrum seeds germinating near the NOID seedling.  My hope is that the helper fungus in the roots of the NOID seedling will inoculate the reed seeds.  It's my best guess that, unlike other orchid seeds, reed seeds already have enough nutrients to germinate on their own.  Even if this is the case I still want to help to spread the fungus that helped the NOID seedling germinate.

The board is sitting on my coffee table without any sort of covering and its right under a bendy octopus type lamp that stays on during the day.  Right now the reed seeds are completely dry.  Hopefully this is giving an advantage to the marginally more drought tolerant individuals.

Next to the NOID seedling's mount is another mossy mount that has a reed seedling on it...

Also on the board are some Echeveria gibbiflora seedlings and a Schlumbergera microsphaerica that I received last fall.  The Schlumbergera grew quite well over the winter.  I'm really happy with how well it has done even though the house was coldish during the winter.   If anybody is interested, this species is currently for sale on eBay.  The vendor also has some other interesting plants for sale.

Getting back to orchids, one of my very favorites is Dendrobium trilamellatum...

This robust epiphyte thrives in habitats in which few other orchids can survive. It occurs from a little south of Cooktown to the islands of Torres Strait, southern New Guinea and the Top End of the Northern Territory. It is a species of the very seasonal and hot open melaleuca woodlands where the wet season usually starts in December with occasional storms building to heavy rain in January to March, followed by a dry season in which virtually no rain falls from June to November. The Yellow Antelope Orchid flowers in spring (July to November) and the flowers are attractive, long lasting and pleasantly scented. They are about three to four centimetres across. In cultivation this species does moderately well, but must be given a dry season and the medium must be well drained. - Bill Lavarack, Bruce Gray, Australian Tropical Orchids

Last month mine bloomed for the first time.  There were only two flowers.  I really wasn't quite in my plant "mood" yet, but because I love this orchid so much, I knew that I'd be really disgruntled with myself if I didn't endeavor to put the pollen to good use.  So I used the pollen to try and pollinate two closely related Dendrobiums...

Dendrobium canaliculatum x (parnatanum x trilamellatum)
Dendrobium canaliculatum x antennatum

Both these orchids now have a seed pod developing on them, but the first orchid's seed pod is twice as large.  When the pods ripen should I sow the seeds on my tree?  I'd like to, in order to select for the individuals that are best suited to my conditions, but I'm not confident that any seeds would germinate.  Right now I'm leaning towards offering the seeds to the curator of the Huntington's succulent collection.... John Trager.  A while back he had an Oncidium cebolleta cross flasked and the seedlings were included as part of the 2012 International Succulent Introductions (ISI).  It was really great to see an orchid offered alongside the other succulent plants.  Since that year no other orchid has been offered in the ISI so naturally I think it's time for another orchid, or two, to crash the succulent party.

If I was going to summarize all of this entry with one word... I'd go with "Californication".  It's a show staring David Duchovny as a writer.  Unfortunately the show isn't about plants but the word "Californication" strikes me as really relevant to the incredible and amazing and fascinating process of the millions and millions of non-native plants growing here in California being selected for, and adapting to, California's climate.  Any Californian who grows non-native plants outdoors helps to facilitate this process, especially when they grow these plants from seed.  In theory, since orchids produce so many seeds, they should adapt the fastest.  But then there's the tricky issue that virtually all orchid seeds require fungus or flasking to germinate.   Well, this issue is only tricky if we assume, or decide, that Californication is truly desirable.

Anybody else a fan of Blade Runner?  The setting is Los Angeles in 2019.  There's an abundance of flying cars, but a scarcity of plants.  Personally, if we are going to err, then we should err on the side of too many plants.  If we're going to give future people something to complain about, then let them complain about an abundance of plants.   Let them complain that California has too many different varieties of tree Aloes that host too many different varieties of orchids that nourish too many different varieties of hummingbirds and harbor too many different varieties of lizards.

Maybe the one movie that best depicts how we should err is Annihilation.  This passage comes to mind...

A few species of orchids are occasionally able to become established in very odd microhabitats.  Withner (personal communication) reports seeing small orchids - probably Comparettia Poep. And Endl. - growing on mango leaves.  Since the leaves last about three years, this suggests that the orchid may complete a life cycle within this relatively short time.  Even more bizarre, Bowling (orchid propagator, Kew; personal communication) told me that he had once seen a tiny Microcoelia Lind. Growing on a spider's web in Ghana!  I very much doubt, however, that either leaves or webs will ever become very important orchid habitats. - William W. Sanford, The Orchids, Scientific Studies

Here's a photo of orchids growing on leaves, here are some photos of an orchid blooming on a leaf, and here's a video of an orchid blooming on a leaf.  Unfortunately I haven't seen a photo of an orchid growing on a spider's web, but I've seen plenty of spider webs on orchids.  Maybe Sanford is correct that leaves and webs won't become important orchid habitats but, given that ants live inside the pseudobulbs of certain orchid species, and virtually all orchid seeds need a fungus in order to germinate, and there are many different orchids that are happy to grow on cactus, I personally wouldn't underestimate potential associations between orchids and other organisms.

[UPDATE]

The largest Laelia anceps bloomed on Jan 2019....