Functional Structural Plant Modeling (FSPM) studies the interaction between plant and environment including architectural and morphological features. VPN (Virtual Plant on the Net) has been developed to analyze the benefits of having a plant simulation model (Virtual Plant Engine,VPE) apart from a graphic client (Virtual Plant Interface,VPI). VPI use Java3D to render the plant in a virtual scene where the skeleton of simulated plants is enriched of VRML-2 features. VPI also allows the user to interact actively with the plant cutting elements and see it re-grown from VPE. Both VPI and VPE have an OO approach to represent and model a wide range of plant.