Those are aerial/adventitious roots that will branch & send smaller roots into the soil when they reach it. You CAN you sever a limb & plant it so it's (physiologically) supported by the aerial roots. If the aerial roots have rooted into the soil, the cutting should take right off, if it hasn't, you'll need to wait for feeder roots to form, just as you would with a cutting.

Al

Thanks Al, I'm planning for next summer, when I should have more time, semi retiring in June. I want to start a few more and like the look of the aerials.

Warmth & humidity is the key to developing lots of aerial roots. For instance, if you put the plant, pot & all, in a white bucket with a drain hole & some gravel in the bottom and cut the bucket off so only the top 2/3-3/4 of the foliage is above the cut off rim, then grow the plant that way, keeping the gravel wet at all times, the tree will put out LOTS of aerial roots.

Al