Orchids That Grow Easily From Seed
 

Orchid seeds don't have enough nutrients to germinate on their own so they require fungus or flasking. Are there any exceptions to this rule?

A while back I learned that reed-stem Epidendrum seeds will readily germinate on moist New Zealand Sphagnum moss in a pot in a zip lock bag by a bright window. Recently I confirmed that the same is true of Bletilla striata seeds...

https://3.bp.blogspot.com/-1Fctx99HG...926_124952.jpg

You can see a larger version of this pic in this blog entry.

The Bletilla seedlings are competing with each other and with Begonia (thiemei and/or carolineifolia) seedlings for limited resources. I sowed the seeds in July.

What about Vanilla and Spathoglottis? Can they also be grown from seed as easily as reed-stems and Bletilla?

Orchids that grow well without in vitro techniques are rare. I think most are terrestrial orchids. Vanilla is not one of those rare few as far as I know, though they are interesting in that you can make stem cuttings of vanilla.

When I first started growing orchids nobody told me that there are some orchid seeds that do not require fungus or flasking to germinate. I discovered on my own that reed-stems can easily grow from seed. Then I happened to find this page which shows Epidendrum radicans and Pleione seeds germinating on bark. It says that the seeds germinated because of the presence of fungus. Not sure if this is really the case.

Several years after seeing that page, I incorrectly thought that the experiment was conducted with Bletilla striata instead of Pleione... so I decided to try sowing some of my friend's Bletilla seeds on Sphagnum and they quickly germinated.

Do you know of anybody who has tried to sow Vanilla seeds on Sphagnum moss? I sure don't.

It's definitely the case that most orchid seeds require flasking/fungus in order to germinate. But nobody, as far as I know, has sat down and tried to find all the exceptions to the rule. So there might be far more exceptions than we realize!

At least on the OB, it has been mentioned on multiple occasions which orchid seeds can be sown ex-vitro. Yes, many of them tend to be terrestrial orchids. However, these are still in the minority when you are looking at the entirety of the orchid family.

It has everything to do with whether the seeds contain endosperm.

I know for a fact that I myself have brought up Bletilla striata as one that can be sown ex-vitro on a few occasions. Other people have brought it up too.

I believe that every species of Bletilla have this capability.

All of the "evergreen" stream side Disas can be sown ex-vitro. These include species such as Disa aurata, Disa cardinalis, Disa caulescens, Disa tripetaloides, Disa uncinnata, and Disa uniflora, just to name a few.

I think the only ones that have not been mentioned were the reed stem Epidendrums. Being able to sow reed stem Epidendrums ex-vitro is not as well known as compared to some of the others that have been mentioned so far.

Yields of germinated protocorms tend to overall be comparatively lower in number if they are sown ex-vitro versus if they were sown in-vitro.

Another hurdle that presents itself is the successful raising of the protocorms to adulthood when they are sown ex-vitro.

I'm not writing off sowing certain orchid seeds ex-vitro as a viable method. What I will say is that sowing orchid seeds ex-vitro is not widely practiced for a reason. Most orchid seeds just do not contain the endosperm needed to make this happen. Germination of the seeds is usually comparatively faster when sown in-vitro versus ex-vitro. There is also the factor of producing higher yields when the seeds are sown in-vitro.

Reedstem Epidendrum seeds certainly don't have endosperm... they are as powdery as those of other epiphytic orchids. I suspect that they are just less picky about what mycorrhizae they will grow with. I find them "volunteering" in other pots - usually Cattleya-tribe plants (so maybe they particularly like the environment created by other members of their tribe)

The endosperm globule in these orchid seeds is microscopic. It is usually directly next to the embryo on one end and it is either much smaller than it or slightly smaller than it. The size of the seed itself or that they are dust-like is not very relevant.

This article does state that some orchid seeds do contain endosperm:

https://www.researchgate.net/profile...01c0930add.pdf

One such reference is on page 13 of the text:

"The seeds of some Disa are very different compared to its related genera. They are unusually large and also contain endosperm, which is unusual in orchids. This strikingly different morphology has also been noted by Kurzweil (1993)." (page 13, Barthlott, Veldman, Korotkova, 2014)

Ok...if I had to make a correction, it might be that Bletilla spp. seeds may not have endosperm attached to the embryo, but rather, they may have a "rudimentary cotyledon". (page 376, Kauth, Dutra, Johnson, Stewart, Kane, Vendrame, 2008)

https://www.researchgate.net/profile...ermination.pdf

"Orchid seeds share a common characteristic of a reduced embryo and the absence of endosperm (Prutsch et al. 2000), with the exception of Sobralia and Bletilla seeds that have a rudimentary cotyledon (Arditti 1967)." (page 376, Kauth, Dutra, Johnson, Stewart, Kane, Vendrame, 2008)

This may be the original article that Joseph Arditti wrote in 1967 that mentions how Bletilla are able to germinate with the help of a reduced cotyledon.

Factors affecting the germination of orchid seeds | SpringerLink

I had difficulties finding literature on Epidendrum spp. I cannot confirm nor deny existence of either cotyledon or endosperm presence in the orchid seeds of "reed stem Epidendrums" at this time.

I might have found what probably accounts for reed stem Epidendrum spp. seed germination without the aid of orchid mycorrhizae - relatively highly developed embryos upon seed development maturation.

It is becoming very apparent that different orchids have different strategies for seed germination. Making blanket overgeneralized statements about all orchid seeds is not a very good way of understanding their actual biology.


If you guys want to know the difference between cotyledons and endosperm, then here's a quick and relatively simple article to read:

Difference Between Cotyledon and Endosperm | Definition, Structure, Formation and Development, Function


The following might be a good read for those interested in orchid embryology:

Orchid Biology VIII: Reviews and Perspectives - Google Books

There are a group of photos on page 316 that show Disa polygonoides and other orchid embryos having lipid reserves, (probably another way of saying endosperm), but I cannot make out heads or tails of the photos. There are captions to those photos that extend down to page 317.

A good number of orchid biologists may have known of certain orchids being able to be sown ex-vitro for a number of years, but this knowledge is not widespread amongst the orchid hobby community.

re Orchids which grow easily from seeds.
 

I was told that some Spiranthes species can propagate ex-vitrio from seeds. The two mentioned were Spiranthes odorata and Spriranthes australis. Both are terrestrials. I have a Spiranthes odorata and there are plantlets around the main plant which has flowered. I have not checked to see if these plantlets are coming from the rhizome of the parent plant (ie vegetative propagation) or from seeds. It's growing too well to disturb at this stage. Joe.

Andy's Orchids has a Spiranthes that regularly volunteers in other pots... I believe it is odorata. He had a couple for sale at the last show. One had seed pods on it and I kinda regret not buying it.

Actually, a while back my friend in Santa Barbara said that Spiranthes odorata regularly volunteers in pots and he would be willing to send me some seeds. I'm going to ask him if he has any available.

When I looked up Spiranthes australis I found this website... Seeds of South Australia. If you click on Browse -> Family -> Orchidaceae you can see a list of numerous species. To the right of each name there might be a seed icon that you can click to see a photo of the seed. Pretty cool!

Some had relatively large seeds...

Pterostylis cucullata
Pterostylis tenuissima
Thelymitra lucida

Epiphyte78 I got my Spiranthes odorata from Andy's Rare Plants. BTW how do you know about Andy's - your profile says you're in Glendale CA - USA; Andy's in The Blue Mountains - Australia?

The Spiranthes australis I saw belonged to an experienced australian native orchid grower and had several 'daughter' plants around a flowering 'main' plant - I was told by the owner that the 'daughter' plants were seedlings off the main plant.

Joe

---------- Post added at 07:37 PM ---------- Previous post was at 07:29 PM ----------

Ooops I confused Andy's Orchids (in Encinitas CA) with Andy's Rare Plants (in the Blue Mountains - NSW Australia). No longer surprised about you comments re. Andy's Orchids.

The rest is correct.

Habenaria repens is at least as weedy as Spiranthes if not more so. Sadly my H. medusa is probably blooming too late to pollinate it with, but I plant to keep some pollen in the fridge until next summer to pollinate a few repens flowers with. Plus my Cynorkis fastigiata is just about to bloom, which is another weedy species. I plan to pollinate it with pollen from C. villosa, if and when it blooms.