Modeling in Renderman is not as easy as in Maya, because Renderman does not have duplicate and move pivot functions. Also, in Maya, one can always see models in windows simultaneously when working; in Renderman, one can only see things after execute the code. This makes modeling in Renderman a tedious task.

Here is the basic shape I made.
The stem here matches perfectly, never the less, it caused some problem in the later steps.

Here I start to duplicate my basic model. I want it to has a fern look, and form a pattern.

However, as I scale the model, I find that its stem does not match perfectly. This problem is due to my trying to form a spiral shape using several pieces of tubes. As the model is relatively smaller, it does not require too many tubes to form the shape I want. Yet once the plant goes bigger, more tubes are necessary to form the shape. To match all tubes then become very difficult.

Eventually I did not success on matching all tubes for the largest fern. Nevertheless, the result I got is good enough.