A fairly "realistic" technique that I have found to create grasses and scrubby brush in Bryce is to use a simple paint tool and litterally paint a large number of bent and wriggly thin lines near the bottom of the image in various grasslike colors. Then take that image map, import it into Bryce and use it as a cylindrical or spherical material on a rock, cylinder, sphere, cone, or whatever. After adjusting the texture scale so that it doesn't repeat iself in the vertical direction, I usually copy it a couple times and randomly resize and rotate them sligthly so it looks more random. This technique seems to reduce polygon count in the scene for grass clumps in the mid-ground (although it starts to look horrible when you get close up). I tend to get carried away with this effect and wind up with a 2 million poly scene in a couple of minutes... I think it's a bad thing when it takes longer to save your scene than it does to render it.