A semi-large Philodendron 'Evansii"

Isn't that showy? :-) Is that diamondy pole its stalk?

Yes, it is its trunk. Although all the aerial roots usually attach to trees or anything they can. I'll post another photo of another one of these plants I took on the same day. It will show off the trunk better.

Thanks. I always thought they rooted in to bark....lol. Now I know that one of mine is just trying to get a grip on the stairs.....lol.

GT:

They will wrap their root around just about anything...and they will grow up until the plant hits the roof. LOL!

In time they will grow up a very large tree if allowed to.

I think I saw some in Aleyna's shots in the botanical garden. All the way up a tree. :-) Could I wrap the aerial roots where I like? Would mine accept my training it up the stair?

GT:

Yes, they can grow up a large tree like Aleyna's photos here also. It's pretty amazing!

If you wrap the aerial roots on the stairs, eventually the roots will grow into the stairs by attaching themselves. It may possible ruin the stairs. I learned from experience when I lived in the San Francisco Bay Area I had a large one on a fence and tried to move it. It left little rootlets stuck to the fence, permanently. I would recommend training one up a large piece of wood.

Look at my other Philodendron photo that I posted tonight and you'll see what I mean. It shows how the roots cling and wrap tightly around each other...which happens quite quickly.