GAMM in mgcv - significance of smooth terms

In the summary of the gam object produced by gamm, the "Approximate
significance of smooth terms" appears to be a test of the improvement in fit
over a linear  model, rather than a test of the significance of the overall
effect of x on y:

	test.gamm<-gamm(y~te(x, bs="cr"), random=list(grp=~1))
	summary(test.gamm$gam)
	.
	.
	.
	Approximate significance of smooth terms:
	               edf       chi.sq     p-value
	te(x)        3.691       11.597     0.017802

Is my interpretation of this correct?
If so, is it possible to calculate a test of the overall effect of x 
from the information saved for a gamm object?

Thanks,
Doug Swain