With this object, we are going to use a picture to shade the leaves.

I'll be working with a clover leaf picture that I found from The Stock Exchange - sxc.hu.

If I clean it up, isolate just one leaf and stretch it out so it will work as a texture for our leaf, we get this:

We need it a little stretched out because our NURB is already tapered, so if the texture is also tapered, it won't cover that much of the surface. I am working with a PNG with transparency, here. The transparency will carry through in Maya.

So, let's create a Lambert shader and go into the attributes of the shader's color.

We'll map it to the geometry Normals of the object and assign an external file.

With a external file defined to be its color, we need to choose what this external file is.

Now, in the Hypdershade window up, and this lambert select, map the In and Out Connections of the shader...

So we can look at the Place 2D Texture node. We'll need to rotate this texture so that it properly matches the geometry of the object. We could also do this in Photoshop. But hey, this is a Maya tutorial.