I do have a cutting of P. Quadrangularis that has put out roots in just water. I left about 6 leaves on it, and of course we have high humidity here these days, which very likely also helped. It's been in the mid- to high-80's for the past few weeks already, and I have at least 4 kinds of passi's that love the heat here and bloom all summer. So by all means, give it heat, give it light, and give it as much humidity as you can!
