Here are the Gymnosperm Videos I mentioned. And if you watched those nicely animated but rather dryly narrated videos here is something completely different.
This is why is is impossible for me to say 'The Larch' with a straight face.
If you need a more basic introduction then here's a nice description of what a trees is. I love the diagram.
Don't forget that if you want to explore any particular topic you can find some ideas by scrolling down to find the 'Labels' on the right hand side of the main page. There are only 4 tagged with the Gymnosperm label but they are all interesting and could suggest areas to explore.