Because the besseae parent is stoloniferous and likes to climb. You can try wrapping some sphagnum around it to keep it moist. I find that doesn't really help much and tend to just pot the plant deeper the next time.
Seedlings in flask have a tendency to not recieve enough light and become leggy. As the internode area gets longer, roots pop out. Your picture looks typical of plants that have not recieved enough light in flask. Its a pretty common problem.
It doesn't seem to hurt the seedlings in the long term, as long as they aren't kept in the flask to long, or the amount of light is very low. You can see in your picture that the new leaves are much more compact (shorter internodal area/ they look normal). They will do fine.
What to do about it? You might want to repot the whole compot. Looks like they could go a bit deeper.
Yes, those are the ones we got together. I was afraid of pottig them any deeper because I pretty much potted them up to the first leaf. They were quite leggy,and yes, they are growing better now. though I have a second one that has clearly a new separate plant/keiki growing from the top of it.
I'm interested to see if it's really another keiki, or just growing out at a weird angle. Don't cut off the leaves, plants need them to gather light energy. I would place that plant in a taller, narrow container w/ medium up to the highest root. Otherwise the plants look good. I have a problem w/ a few Woodstream crosses that the leaves dont open and the next leave is squeezed inside, something in their breeding program? With your roots you just have to make sure they don't dry out. Good luck.
I have seen that 'branching kieki' type growth in flasks kept in low light as well.
I would cut off the lower leaf and pot the plant to the poin that the new roots is. That is the same point where the growth of the plant looks to have 'stabalized' and all further growth should be normal.
Why are you still seeing these wierd growths after you have deflasked and the plants are getting a more normal amount of light? The plants initiate roots and leave (and branches) deep in thier tissue, long before we see them on the surface. Those roots were growing befroe you deflasked, you just couldn't see them.
Thank you, Heather. I was thinking of that thread, but hadn't seen the additional follow-up beyond Jason's potting demo. That's very interesting. As this is still a new seedlings, just out of flask, I'm thinking I may just let the little guy sit a bit longer - maybe add some more medium to the one that's getting the lower root growing, and maybe the single really tall plant as well.
I've had Barbata sp. paphs do stuff like this on young and old plants too. Often the plants will "lie down" on the substrate and root and keiki at the places where it is in contact with the potting mix.
As long as humidity is high those "aerial roots" will be ok without being buried, and let the lower stem and leaves harden up a bit before getting buried, and possibly starting a rot on the lower stem.