Structural equation model in R

I want to do SEM on my dataset (plant ecology) in R. Can you introduce
someone to help me?

Mehdi,

I highly recommend Jim Grace's book, "Structural Equation Modeling and
Natural Systems" and his 2008 paper, "Structural Equation Modeling for Observational
Studies" (The Journal of Wildlife Management 72(1):14-22.)

The second is valuable for environmental and regulatory science needs as
these data are all observational and not experimental.

The R repo contains (at least) the packages 'sem' and 'OpenMX'.

HTH,

Rich