I'm looking for a very low growing ornimental grass to fill in an area
in my very small back yard. I want it to be a lawn type not a clumpy or
high growing type. Is there such a type? Any help would be greatly
appreciated! Thanks in advance.

BMW

I can't think of any lawn type grass other than well, lawn grass. I
don't know in what part of the counry you're in, but I'd get a piece of
zoysia sod from the garden center and be done with it. Here in the
South, zoysia is really the best type of grass for sun and shade and
makes a very beautiful carpet.

There are several spreading ground-cover types of Sedum that I could
also recommend for filling in an area. Sedum tetractinum and Sedum
sexangulare are good spreading types that I've had good luck with.
They wouldn't be good for foot traffic, though.

There are also several herbs that can be grown as groundcover and can
stand foot traffic. Some of them would probably look grassy like the
thymes.

Is this an area that you would want to mow? Will it be walked on?
Etc...

Quoting bmw:
I'm looking for a very low growing ornimental grass to fill in an area
in my very small back yard. I want it to be a lawn type not a clumpy or
high growing type. Is there such a type? Any help would be greatly
appreciated! Thanks in advance.

Do a google search on "dwarf mondo grass" and see if it might meet
your needs.