There are a wide variety of miniature cacti, many with different features. We have the traditional candelabra (tree) cactus with various number of arms. Then there is the ball cactus and pear cactus plants. Not to be outdone by the barrel cactus. Not only are these done with different features and families, but with a single 3mm base height of 1x1inch size or the openlock bases which allow snapping to terrain.
These can be combined with my openlock prairie tiles found here.
There are over 25 piece available and this is not including, of course, resizing and mirroring.