Jim can correct me if I'm in error on this, but I think those Spanish bayonets are in the Yucca family. That particular variety is what we refer to as a hard Yucca, because it's leafs are stiff, as compared to some of the succulent variety whose leafs are soft.

I took some great pictures of Trumphet Plants they will be developed tomorrow (Saturday), I'll try to post them so you can see what they look like. They are a small red plant that usually grow no higher than around 24 inches.

I ran into a field of them, and I snapped a few shots.

Take care,

Doc